Historians of chemistry may remember Clapham Common
John Venn followed the path of his evangelical father, Henry
Like nature, society was subjected to “experiment” in the eighteenth century. In all good faith, the evangelicals could support a poorly conceived experiment on society: children from central Africa were brought to Clapham, where they were taught to be civilized in the English way. For a time the children roamed the Common, invited into the neighboring houses by their curious owners; unaccustomed to the “rigors of the English climate,” most of these children died.4 The recent French Revolution, Thornton believed, was an “experiment made upon human nature by men insensible of our natural corruption, an experiment by which they expected to show the advantage of a general deliverance from restraint—the superiority of Reason over Revelation. When men are thus left to follow Nature, and are released from their subjection to the laws both of God and of civil society, iniquity will not fail to predominate.”5 The logical outcome of the French Revolution was Napoleon, who was expected to arrive momentarily at Clapham. Evangelicals were not pacifists; Venn published Reflections in This Season of Danger, in which he declared that “religion not only permits but enjoins us to defend our property, liberty, and lives against the attacks of violence.” The parish was defended by the Clapham militia, commanded by Samuel Thornton
Benevolence and charity
In 1768 the Council of the Royal Society accepted the request of the youthful Joseph Banks to accompany Captain Cook
Banks’s assertive presence on Cook’s voyage foreshadowed his activity as president of the Royal Society. As patron and administrator, he exerted a remarkable personal force on English science
Cavendish publicly gave his approval of Banks’s presidency during the dissensions in the Society, as we have seen, and implicitly he gave it over the thirty-two years he served in the Royal Society under Banks. Long accustomed to working together in the Society, and to meeting socially at the Sunday conversaziones and elsewhere, Cavendish and Banks were friendly, but not close.
By contrast, Cavendish and Blagden were “intimate,”to use Blagden’s word
Blagden’s unhappiness was multiplied by a task Banks had assigned him, to find a method of determining the correct excise duty
Blagden complained that he should have been paid for this task. Banks replied that he had performed many tasks for the government and never thought of reward, but he would look into it if Blagden would tell him what he expected. Blagden’s resentment of Banks had been building. From the time he returned from America, Blagden said, Banks had taken him for granted and deceived him. When he accepted the job of secretary to the Royal Society during the dissensions, Banks made him a “tool of his ambition.” Blagden believed that Banks would advance him in society and improve his fortune, but instead he discouraged Blagden from pursuing his profession, medicine, and even from marrying, his only purpose being to keep Blagden dependent on him. Banks defended his character and conduct.20 Blagden’s rancor at Banks continued, as did their correspondence until it became tiresome.21
The draft of a letter by Blagden, which was probably written in 1790, gives a clear idea of the extent of his disappointment. The recipient of the letter is Blagden’s benefactor, who could be Cavendish though more likely he was Heberden
When Blagden considered marriage, Cavendish entered into his plans. In 1789 the potential wife was picked out, Ann Osborne, and in November of that year Blagden asked his brother to inform him about her. Would she enjoy Blagden’s kind of company and “particularly would so far enter into the pursuits of my friend Mr. C. as not to think some portion of time spent in his company tedious? This would be a matter of the utmost consequence to us both. You will easily suppose I do not mean that she should enter into our studies, but simply that she should not find it disagreeable to be present when such matters were the subject of conversation, or when any experiment which had nothing offensive in it, was going on.”23 Blagden contemplated the three of them together, Blagden, his wife, and Cavendish. He was concerned about her reaction, not about Cavendish’s, calling into question Cavendish’s severe misogyny, as described by Wilson.
Cavendish is said to have accepted Blagden
It seems clear that in 1789 Blagden was on good terms with Cavendish and not with Banks. That summer Blagden contemplated going abroad with Henry Temple, second Viscount Palmerston
As it turned out Palmerston did not go on to Italy to spend the winter of 1789–90 as planned, and in the late fall Blagden
From what he could learn, Wilson concluded that Cavendish and Blagden’s break “did not occur till at least 1789.” We agree; as we note above, as late as November 1789 Blagden was concerned about how his potential wife would react to his work with Cavendish. A year later, Blagden excused himself from a trip he had planned with Palmerston because of “some experiments at Clapham.” Cavendish and Blagden continued to be much together, but their relationship was less close than it had been. We can safely assume that Cavendish did not want to quarrel with Banks, but this was unlikely the main reason. Thomson said that Blagden “left him.”39 Blagden wanted to make changes in his life, which first of all had to do with his obligations to Banks, and a reduction in his obligations to Cavendish may have been included. In late 1789, while he still fully intended to continue his association with Cavendish, he described his financial situation to his brother to pass along to his prospective wife: his stocks were worth between 9 and 10,000 pounds, and his income was 250 pounds a year from his half pay in the military and his secretaryship of the Royal Society; he was “not without other expectations, but of these nothing can be said.”40 Cavendish did not contribute to Blagden’s income, but Blagden’s “expectations” probably had to do with him in the event that he married. As it turned out, Blagden did not marry, and Cavendish consequently would not have entered his subsequent plans. Another consideration was that Cavendish was not as busy as he had been and his having less need for Blagden’s help, their separation may have been mutually desired. About the personal side of their association we know little; their natures being very different in some ways, it is possible that their collaboration was trying. If his relationship with Cavendish eventually did not suit, Blagden’s regard for Cavendish did not change. Writing to Banks from Paris in 1802, Blagden
Through the Devonshire and the Kent dukedoms, Cavendish had an enduring connection with the world independently of Blagden, Banks, and his other scientific colleagues. For most of his adult life, the head of the Cavendish family was William
The fifth duke and his (first) wife, Lady Georgiana Spencer
From abroad, the duchess asked Blagden to tell her about “any chemical, mineralogical, or philosophical novelty” and to give her compliments to Cavendish,50 and when she and Blagden happened to meet abroad, they spent an evening with “much talk about chemistry & mineralogy.” Blagden noted in his diary: “Dss of Devonshire said she was quite wild with studies of that nature: asked much about Mr. Cavendish & his pursuits”; “much talk with the Dss about Sir Jos. Banks’s meetings, Mr. Cavendish.”51 The duchess called on Cavendish at his house,52 and Cavendish called on her, often, it is said. Once when Blagden came to see her at Devonshire House, he found Cavendish there engaged in scientific talk.53 In wanting to be informed about scientific advances and about Henry Cavendish’s activities, the duchess overcame his shyness and his alleged misogyny. To have his company she had only to keep to his subject, science, her lively curiosity no doubt doing the rest.
In his later years, Cavendish worked on nearly all of the subjects he had in his early years, though the proportions changed. Astronomy
Around London there was a series of observatories
In 1781 William Herschel
At the Royal Society Club, John Playfair found that members paid little attention to guests, of whom he was one. The exception was Alexander Aubert, whom Playfair found “a very polite man, and a great consolation to a stranger.”57 (Fig. 12.3). This detail captures a truth about Aubert: he was observant and helpful. He seemed to have had no personal ambition in astronomy
Cavendish saw Nevil Maskelyne
If Cavendish did not meet Michell
Hardly had Cavendish
Christiaan Huygens’s account of an aerial telescope was published in the Philosophical Transactions in 1684. To dispense with the “heaviness and disproportion” of the telescope tube, Huygens cut out “almost the whole tube, saving only a small part of it near the objective glass, and somewhat towards the Eye glass, ordering these two extremities in such a manner, that they may do the same service, as if the whole tube of one piece should be employed.” He described a fifty-foot mast for erecting an aerial telescope of seventy-foot focal length, a stand for steadying the observer’s arms, a lantern for illuminating the object-glass so that it could be found at night, and a cord for aligning the eye-glass and the object-glass.71 Never very popular in Britain, the aerial telescope was hard to manage, and on dark nights the object-glass was difficult to see without artificial light, alllowing stray light to enter the eye-glass. The alternative, a telescope of long focal length that came with sliding tubes, was also hard to use, affected by wind and vibration.72 The Royal Society considered fixing the Huygens telescope to a tall, solid building, but they could not settle on any tall or solid enough. Halley was ordered to consider the scaffolding of St. Paul’s Cathedral. James Pound
At this juncture, Henry Cavendish enters the history of Huygens’s telescopes. In November 1785 the Council of the Royal Society gave him permission to borrow the 123-foot telescope and also the other Huygens object-glasses, which he kept for three years. Among Cavendish’s manuscripts is a study by him of a ship’s mast, which we take to be the mount for the Huygens telescope. It begins with fundamentals: “According to Newton the resistance of wind to a globe is equal to […] and therefore if wind is 60 miles per hour….” To judge from his calculations—he determined the pressure of wind on two cylinders of unequal diameters each 40 feet in length—the Huygens telescope was erected on a wooden mast 80 feet high, supported by 20-foot struts planted 11 feet from the base. A horizontal piece was fixed to the mast.76 Well secured, the mast remained in place long after Cavendish died, identified in a description of his property this way: “In a padlock at the back of the house is a mast of a ship, erected for the purpose of making philosophical experiments.”77 The mast towered above Cavendish’s house as if it were the home of a nostalgic man of the sea.
In March 1786 Aubert
From the 1780s Cavendish devoted a large body of work to the orbits of comets
Newton showed that a comet moves on a parabolic path, which in the case of a returning comet coincides with a highly eccentric ellipse. In principle three observations determine the elements of the path, but in practice it was a difficult problem for astronomers. A forty-year-old method by Boscovich
In December 1788, while looking for the expected return of the great comet (it failed to return), Caroline Herschel discovered a faint comet, her second. Evidently with this in mind, Cavendish wrote a substantial paper laying out his method for computing the orbits of comets, both parabolic and an elliptical, from three observations. His method made use of a globe covered in white paper on which the ecliptic and various circles and points were drawn. He gave his study of comets’ orbits to Maskelyne, who suggested a planisphere made by Adams in place of Cavendish’s globe. Along with this and other comments on Cavendish’s paper, Maskelyne sent him the observations he had requested, those for Caroline Herschel’s recent comet, the orbit of which he wanted to compute using his method.88 (Fig. 17.2). In due course Cavendish wrote to Maskelyne that he had been “so much taken up about this & other matters” that he had not been able to study his comments on his method. He said that up to this point the method caused “rather more trouble than I imagined it would be before I tried it but on the whole seems as if it would prove an useful method especially if proper tables were made which if I knew of any one that I could employ to compute them I would get done.” He wrote a paper on the disturbance of a comet’s orbit in passing planets,89 a variation of the problem of the alteration of the orbit of a planet by another planet, which he also worked on
Years later, Cavendish returned to comets to make lengthy studies of methods of computing their orbits91 and to compute the path of the first of two comets discovered by the French astronomer Pierre Méchain in 1799.92 After pointing out a small error in a logarithm, Cavendish told Maskelyne
The very considerable labor Cavendish devoted to the paths of comets can be understood as a response to problems astronomers addressed at the time. There may have been an additional incentive too. Once regarded as transient phenomena of the atmosphere, comets were one of the triumphs of the Newtonian world. These seemingly capriciously appearing objects were found to be subject to the force of gravitation and therefore to theoretical calculation and prediction.94 They recall the earliest record we have of Cavendish’s thoughts, the poem
The final unpublished work of Cavendish’s we consider belongs to optics. Among his papers we find a copy of a letter written by the astronomer William Ludlam
Dolland repeated Newton’s experiment, finding both the experiment and Newton’s dispersion law wrong. With a double prism of glass and water, and with an adjustment of the angle of the water prism, he was able to achieve refraction without dispersion into prismatic colors. With further experiments with prisms, he found that by combining two kinds of glass with different powers of dispersion in the right proportion, he could again obtain refraction without dispersion. The success with prisms carried over to lenses, enabling Dolland
On a tour in Switzerland, Blagden
Cavendish’s first experiment was a comparison of a prism of “glass from Switzerland” with a prism of ordinary flint glass (Fig. 17.3). Given the timing we suppose that the glass from Switzerland is the one Blagden received from Guinard
Cavendish’s experiments with light and prisms were probably connected with his interest in astronomy
Cavendish’s last five papers published in the Philosophical Transactions all had to do directly or indirectly with astronomy
Cavendish’s interest in the aurora extended beyond the calculation of its height. By analogy with the aurora borealis, he suspected that auroras of this kind consist of parallel rays of light shooting skyward, and he encouraged “people to attend to these arches” to help decide if his hypothesis was “true.”
In 1792 Cavendish published a paper on the Hindu civil year.
Cavendish began his paper by pointing out that much was known about Hindu astronomy but little about the Hindu civil year, and what was known varied, in part, because different methods were used in different parts of India. To clear up this uncertainty, Cavendish asked the Sanskrit scholar Charles Wilkins
Cavendish described the almanacs beginning with Benares. He characterized its preface as a man of the Enlightenment might: it “begins with an invocation to the Deity, and then gives a whimsical account of the four Yoogas, or ages, and of the inferiority of each succeeding age to that preceding it, and concludes with astrological remarks.” The almanac contains eleven columns, without titles or explanations, “but by a careful examination of the numbers, a person acquainted with astronomical computations may, without much difficulty, find out their meaning.” Cavendish went through the columns one by one, giving his interpretation. The almanac contained other information such as tables of diurnal motion, places of the Sun and planets in the Hindu zodiac for each week, lunar and solar eclipses, times when the moon and planets come to certain situations, about which, Cavendish said, “there is not a great deal which I understand, and what I do, is not worth taking notice of.” There were some tables and figures that he thought “relate only to astrology,” falling outside his area of interest and competence.
Cavendish’s last publication was about a method for dividing astronomical instruments
As was the practice up to his time, Bird made his divisions by hand, the accuracy
In 1785, Cavendish communicated to the Royal Society a paper on dividing circles by John Smeaton
Between 1775 and 1778, John Troughton
In 1804, Troughton had perfected a new method of dividing circles, which he used in graduating the Goombridge Transit Circle, a four-foot transit instrument he made for the astronomer Stephen Goombridge
Troughton submitted a paper containing his new method of dividing circles to the Royal Society in 1808, and the next year it was published in the Philosophical Transactions.124 He said that Bird was the greatest divider of his time, and after him came Ramsden, Smeaton, and his brother John. For his part, he said, he had quickly come to reject beam compasses, finding that he could not bisect two points “without enlarging, displacing, or deforming them” with the tools then in use. Recognizing that only “turning” led to perfection, he used rollers to divide a circle, marking off the revolutions. In the paper Troughton mentioned the six-foot circle he was making for the Royal Observatory.125
Troughton’s paper is mainly about reducing errors. Two other papers at the time dealt with the same subject. The astronomer John Pond
Cavendish pointed out the great difficulty in the common method of dividing beam compasses, which required placing a point halfway between two nearby scratches on the limb of the circle, an action that was hard to achieve without the point slipping toward one or the other scratch. He supposed that this was why Troughton invented an alternative “ingenious method of dividing,” which induced him to see if the older method of beam compasses could be modified to avoid the objection. His change was to use a beam compass with one point instead of two, replacing the second point with a microscope, in this way eliminating the need to set the point of the compass into any division, and the objection to the “old method” was “entirely removed.”128
In Cavendish’s apparatus, a movable frame rests on the circle to be divided, and there is a single beam compass with a retractable point near one end and a pivot at the other, fitted with a microscope that slides from one end of the beam to the other (Fig. 17.4).129 Horace Darwin describes his method concisely: “the circle was first divided into 6 parts by setting a beam compass with the points apart at a distance equal to the radius. These spaces were divided again by the beam compass, sometimes into two equal parts, and sometimes into three and five equal parts, and so on till quite small spaces were left. Errors have to be calculated and allowed for, and the process is most laborious and slow.”130 Both his and Troughton’s methods were free of the inaccuracy of setting a point of a compass in the center of a division, but his required “much less apparatus” than Troughton’s and was “free from any danger of error” from irregularity and slippage of motion of a roller, and it had an additional “considerable advantage” in being free of mistakes in “computing a table of errors.”131 His method had “much advantage” over the common beam compasses in accuracy
Cavendish’s method does not seem to have been adopted. It was for making original divisions, whereas later instruments were graduated using dividing engines, which copied existing divided circles. What is important here is the kind of instrument he was concerned with. His final contribution to science was about a tool for making instruments capable of measuring with more exactness. We close this section with a table from Troughton’s paper in the same volume of the Philosophical Transactions as Cavendish’s. In parts of an inch, the greatest error of six standards were, in order of accuracy
Such accuracies had practical as well as scientific and technical significance. Troughton called attention to the place in the ranking of General Roy’s scale, which was important because Roy used it to measure
It has been suggested that Cavendish’s reluctance to publish more of his work was a consequence of his class and wealth
A number of general explanations of Cavendish’s practice of publication have been suggested. One of them is Blagden’s, mentioned earlier: Cavendish published everything he was satisfied with, and if he did not publish, it was because he was not satisfied. Another reason is that he carried out researches only or mainly to satisfy his curiosity and was indifferent to their publication. A problem with this is that he was committed to the advancement of science
Cavendish’s laying aside researches after initially intending them for publication may not have had entirely to do with the work at hand. William Heberden, who drafted the certificate for Cavendish’s membership in the Royal Society, wrote a paper (which he did not publish) on the advantages of writing but not publishing. Writing, he said, “enlarges the mind and improves the taste,” a sufficient reason for going to the trouble. The writer, however, if he “has already established a reputation, loses it as soon as he ventures to give anything to the public.” The happiest writer, Heberden thought, was one who wrote “always with a view to publishing, though without ever doing so.”135 For a person who relished his privacy as Cavendish did his, Heberden’s advice might have seemed not only clever but wise. There were other ways of contributing to science that did not require publishing
If Cavendish had been born one hundred years later, or two hundred, he might have directed a scientific institute, and there is reason to think that he would have been good at it. His publications on heat were commentaries on experiments carried out under his direction. He directed meteorological observations at the house of the Royal Society and for a meteorological station he set up on Dartmoor. He instructed travelers to make observations of the heat of wells and springs for determining average climates of the world. He drafted scientific instructions for voyages of discovery. He did basic planning for two major Royal Society projects, observing a transit of Venus and measuring the density of the Earth. His house at Clapham Common was a live-in forerunner of a research institute. Because of a combination of traits—intelligence, dexterity, knowledge, and a sense of fairness—he had an authority he did not have to assert. We recall these facts about him to provide the background for certain experiments he devised for the public good in his later years.
In his Sentimental Journey through France and Italy, Laurence Sterne
In 1787 Charles Jenkinson
The industrialist Boulton
Cavendish planned the experiments to determine what kind of gold coin would best resist wear. To replicate the wearing of coins in Laurence Sterne’s pocket, and any other kind of wear arising from their circulation, he designed machines
The two main questions were: first, whether soft or hard gold experiences the most loss to friction in the circulation of coins; second, whether a smooth coin or an embossed coin wears least. The experiments showed that when coins of the same qualities are rubbed together, the most ductile coins wear least, and that when dissimilar coins are rubbed together, the reverse is the case.
The loss of weight in the experiments in any case was found to be miniscule, of the order of one grain per coin.The general conclusion was that whatever differences there are between different gold alloys, the loss that coins experience in normal circulation is trifling. The worn look of coins is explained by the prominences being simply pressed into the mass of the coins, not by any appreciable loss of weight. Any significant loss of gold would have other explanations.145
The experiments on the composition of coins turned out not to be particularly useful to the government, for they confirmed the practice of the minters, who proceeded with their alloys by experience without the aid of science,146 but they did bring forward new facts of considerable scientific value. Hatchett said that knowledge of metal alloys had not “kept pace with the rapid progress of modern chemistry,” being scarcely superior to what Pliny and the ancients knew.147 As for knowledge of wear, a recent commentator writes, the grasp shown by Cavendish of its complex nature “was masterly; his work could have been studied with advantage by investigators a century later.”148
17.9 Coinage Apparatus. This drawing shows the apparatus invented by Cavendish for measuring the wear of coins, built for him by the instrument maker John Cuthbertson. Twenty-eight pairs of coins are pressed and rubbed together by turning the crank. Each pair of coins is separately weighted, and the frames holding the top and bottom coins vibrate at different rates to reduce grooving. Charles Hatchett, “Experiments and Observations on the Various Alloys, on the Specific Gravity, and on the Comparative Wear of Gold. Being the Substance of a Report Made to the Right Honourable the Lords of the Committee of Privy Council …,” Philosophical Transactions 93 (1803): at end of volume.
There is a sense in which coinage and nature posed a similar problem. In his researches, as we have seen, Cavendish repeatedly introduced a “standard” by which to measure certain phenomena or substances, and he referred to substances or powers as being in a certain respect “equivalent.” The same terms were used to understand the wealth of nations. In a letter to Liverpool
There was a long-standing tradition of scientific service in the government in matters of coinage. Newton
For decades Cavendish served two institutions, the Royal Society and the British Museum, and in the last decade of his life he served a third, the Royal Institution. The last named was the creation of Benjamin Thompson
Both Cavendish and the duke of Devonshire paid their fifty guineas about a year after the Institution was founded, by which time it looked respectable, with a substantial aristocratic representation.158 The governing body consisted of nine managers, elected initially from the proprietors, and Cavendish promptly became a manager.159 The meetings of the managers were irregular but frequent, attended as a rule by only three or four managers along with the secretary and treasurer, with Cavendish the most faithful attender. He was also a conscientious member of the “scientific committee of council,” a standing committee set up to oversee the syllabus and scientific experiments, which included Blagden
17.10 Royal Institution. Distinguished Men of Science. Engraving by William Walker around 1862, from a drawing by Sir John Gilbert. The full title is “Distinguished Men of Science Living in Great Britain in 1807–8.” The setting is the library of the Royal Institution, but the men shown in the print never gathered in this room. The artist created the group from individual portraits. Henry Cavendish is placed in the front, sitting apart, his eyes downcast; perhaps this is the artist’s interpretation of Cavendish’s solitude in company. Cavendish’s profile and dress are based on William Alexander’s sketch, with obvious differences: Cavendish’s hat is removed; he is seated instead of walking; he faces the other direction; and he is made to appear thirty years younger. Cavendish was a manager of the Royal Institution from 1800. Wikimedia Commons.
Cavendish had long been a subscriber to the Society of Arts without taking part, whereas he was fully involved in the affairs of the Royal Institution from the start. The difference is likely explained by the stronger connection to science in the Royal Institution. Cavendish supported formal cooperation between the Royal Institution
In addition to his concern with the practical applications of heat
When Davy arrived at the Royal Institution in 1801, he was received by Rumford, Cavendish, and Banks, who promised him any apparatus he wanted for his experiments.175 When Cavendish died, his proprietorship in the Institution was inherited by his heir Lord George Cavendish, from whom Davy obtained some of Cavendish’s chemical apparatus. Five months after Cavendish’s death, Davy received permission from the managers to bring the apparatus into the Royal Institution for use in experiments and lectures.176
At the beginning, Rumford published a prospectus, explaining the need for the Royal Institution. For men of science, he wrote, a discovery was its own reward. Detached from the “ordinary pursuits of life, they lacked the “proper “moral and intellectual habits” to “descend from the sublime general theories of science and enter into the detail of weight, measure, price, quality,” the practical side. The Royal Institution
The Royal Institution benefited from Cavendish’s services, and in return it enriched his life. In his last decade, through his activities at the Royal Institution, he was associated with several of the most talented physical scientists in the country: Rumford, Young
Rumford reported that after Banks came Maskelyne, Cavendish, Herschel
After Cavendish’s death, reports of his wealth appeared in various publications. Georges Cuvier
Wilson said that he was unable to discover the overseas general, or learn whether it was an uncle or an aunt who left Cavendish a fortune. He thought that this was not of great significance, but the date when Cavendish acquired the fortune was important because it was then that Cavendish acquired financial independence. According to Biot, Cavendish was forty when he became independent. Wilson put an upper date on it in the belief that Cavendish settled an annuity of £500 on Blagden in 1782 or 1783, when he was fifty-one or fifty-two, implying that he had to be well off by then to afford it.193 Wilson was right about the time.
The wealth of Charles and then of Henry Cavendish had three sources: the family settlements and legacies, without which there would have been no wealth; financial prudence; and the public debt of the kingdom. In addition to the three revolutions we have discussed, scientific, political, and industrial, Charles and Henry Cavendish were beneficiaries of a fourth “revolution,” this one commercial
The perpetual annuities owned by the Cavendishes were controlled by a new policy introduced in 1751. The outstanding loans paying 3%, some through the Bank of England and some through the exchequer, were consolidated into a single fund, which was named the “3% Consolidated Annuities,” or “consols” for short. Other annuities paying more than 3% were united in another fund now paying only 3%, which were named “3% Reduced Annuities.” Both of these funds were managed by the Bank of England, which paid out interest, or “dividends.” The dividends were paid twice yearly; in other words, 3% annuities paid 6% annually. On stated days the dividends were drawn and signed for; if the owner of the stock was not present, the dividends were deposited through power of attorney with the Bank or the trading companies.195
Most of the owners of Bank of England stock lived in and around London. They were a varied lot, with many migrants, Huguenots and Spanish and Portuguese Jews, a good many gentry, gentleman, and peers, especially dowagers and ladies, corporate bodies such as Cambridge colleges, and increasingly spinsters and widows. Investors usually bought stock and kept it, withdrawing only dividends or else reinvesting them. Most of the stock was held by a very few persons, who included Henry Cavendish.
To the world, Cavendish’s
Before his father’s account was transferred to him, Henry Cavendish had stocks in his own name worth £17,388:198
The total comes to £161,100 in funds from his father. On the last day of 1783, through his father, he inherited his aunt Elizabeth Cavendish’s
Adding the above amounts gives Cavendish’s wealth in funds in 1784 as £275,588. At age fifty-three he was moderately rich. He lived another twenty-five years, over which time his wealth quadrupled, so that at the end he was very rich. We can see how this happened by looking at the growth of several of his funds.
Bank Stock. Lord Charles had £25,815 in Bank Stock.200 Cavendish did not touch this fund, which at his death was worth £71,120. At that time, it represented about % of the value of his funds.
Reduced 3% Annuities. In October 1783, Cavendish received £18,285 from his father’s estate, which he added to his own holdings, £14,500. In January, he received £22,100 from Elizabeth Cavendish’s estate. Between 16 January 1782 and 5 [?] 1783, he sold £8500 of this, leaving £58,385 in his account.201 The value of the fund on several dates gives a picture of its growth:
13 June 1788. £86,000.202
2 November 1791. £115,000.203
5 April 1801. £216,504.204
5 July 1805. £281,528.205
5 April 1807. £347,809.206
1810, at his death. £433,852.207
Consolidated 3% Annuities. In 1782, Lord Charles held £47,100 of this stock. On 3 September of that year, he added £7000, and on 3 December, £8000, giving a total at the beginning of 1783 of £62,100.208 The value of Henry Cavendish’s account in this stock was:
7 January 1784. £137,100. The increase came from Elizabeth Cavendish
15 August 1786. £145,000.210
2 November 1791. £172,600.211
17 November 1796. £240,739.212
12 April 1802. £322,857.213
9 September 1808. £505,000.214
New South Sea Annuities. At his death, Lord Charles had £48,900 in this fund.215 From October 1776, Cavendish had £1100 in it. On 23 August 1783, £872 was deposited by the earl of Hardwicke, a relative on his mother’s side. By 5 July 1793, the value of his account had increased to £59,255, where it remained to the end of his life.
As in other ways, in matters of finance Cavendish followed his father’s course, investing in gilt-edged securities and almost never touching them. Shortly before his father’s death, when he was establishing an independent life and considering buying properties, he sold a small part of his securities, receiving £8500 for them, but that was the exception. During the Napoleonic Wars, the government offered a higher return on loans and very substantial bonuses as a percentage on capital on top of the half yearly dividends,216 but we see that throughout the time after his father’s death Cavendish’s account rose fairly steadily.
2Funds held in trust. All of these stocks and annuities stand in the names of Cavendish’s first cousins the earl of Hardwicke, Lord George Augustus Cavendish, and Lord Frederick Cavendish. There were five funds, with face value £21,755 and actual value £17,832. Most of the value was in one fund, Old South Sea Annuities.
4Balance in banker’s hands. £11,373.217
Apart from his funds, Cavendish’s wealth at the end of his life consisted of his land and his houses at Clapham Common and Bedford Square together with their contents, and probably other property.218
Cavendish’s worth was in line with great fortunes in the eighteenth century. Lady Bute was said to have inherited around £800,000 in 1761 from her father, E. Wortley Montague. Lord Bath was said to have left £1,200,000 at his death in 1764. Sir Samuel Fludyer was said to be worth £900,000 in 1767.219
In his biography of Cavendish, Wilson
Cavendish’s order produced the following transactions. On 26 March, he bought £8400 of Consolidated 3% Annuities and £4000 of New South Sea Annuities. On 30 March, he bought £4383 of New South Sea Annuities. On 20 April, he bought £8333 of Reduced 3% Annuities and £5000 of Old South Sea Annuities. On 24 April, he bought £2000 of the same. On 26 April, he bought £1370 of Reduced 3% Annuities. The total came to £33,486. Cavendish paid the actual value, which was below par, plus commission, £25,965, which is just under the £26,000 Cavendish specified.222 After receiving a purchase order like this from Cavendish, Robert Snow, his main contact with his banker Messrs. Denne & Co., would write to him, “Agreeable to your order of the [date], we yesterday purchased [the amounts and the funds]…,” closing with, “This sum is as near the order as possible to keep the stock in even sums.” Cavendish’s directions were straightforward and consistent; his dividends were reinvested alternately in four securities: new and old South Sea annuities and consols and reduced 3% annuities, primarily in the latter two.223 His farm and other rents went directly to his bankers, and his business was transacted through them. He had enough wealth that he did not have to spend much time with it, an ideal life which he did not want disturbed by house calls from his bankers.
As Biot said, Cavendish was the richest of the wise, and insofar as his investments were concerned, he was at least one of the wiser of the rich; over the long run, during the years in which he amassed his fortune, he could hardly have managed his inheritance better than to reinvest its earnings in consols and reduced 3% annuities, especially since he was a man who had other things to do with his days than to spend them in his counting house.
From what Wilson
In the one published comment on Cavendish’s religious persuasion, Biot
In the last two decades of his life, as we have seen, Cavendish shared Clapham Common with evangelical members of the Church of England known as the Clapham Sect, who were distinguished for their spiritual intensity. They were troubled by what people did on Sundays, which they insisted should be dedicated to quiet devotion.226 At a meeting in 1798, the inhabitants of Clapham parish agreed unanimously that in the interest of both the individual Christian and civil society, it was “highly improper, on that Day [Sunday], to exercise our worldly occupations, to travel, except in cases of urgency, or for purposes of benevolence, or to employ our domestics in any thing interfering with their public or private religious duties.”227 In this way, the evangelicals imposed on Clapham Common the quiet contemplation of the life to come, known later as the Victorian Sunday. There was a call for the prosecution of violators. Wilson noted that Cavendish’s decisive experiment on the composition of water was done on a Sunday. We add that Cavendish performed the fifth part of his experiment on the density of the Earth on a Sunday in 1797. He treated Sunday like any other day of the week; he worked, doing what he always did. He had no known run-ins with his evangelical neighbors. After his death, his house had a brush with the movement; John Thornton, son of Samuel, a member of the Clapham Sect, lived in the house for a few years.
Wilson received a few comments on religion from his inquiries. A member of the Cavendish family heard his grandmother say that Cavendish once came to a christening, but he may only have stayed for dinner. A fellow of the Royal Society said that “as to Cavendish’s religion, he was nothing at all.” A neighbor of Cavendish’s at Clapham believed that he “never attended a place of worship.”228 Other than to list a church as a landmark in taking bearings, his one known reference to a church occurred during a dinner of the Royal Society Club, when he said that some wood at Clapham Church was eaten “thro’ by the insects… working their way out.”229 In the absence of any outward display of interest in religion on Cavendish’s part, Wilson concluded “that the World to come did not engross his thoughts.”
Newton wrote in the Principia that the discussion of God “does certainly belong to Natural Philosophy.” In the previous edition of this biography, which I prepared with Christa Jungnickel, we said correctly that Cavendish did not record any thoughts on religion in his writings on natural philosophy. We did not mention in this connection Cavendish’s contribution to the University of Cambridge’s volume of lamentations in Latin in honor of the crown prince Frederick
The later years of Cavendish’s life were ones of peril for the nation
Toward the end of his life, as at any time during it, what was most conspicuous about Cavendish was his steadfast desire to learn more about and to practice science. When Blagden was given a paper by Herschel to look over, he knew Cavendish was the “best person” to read it,233 and this was one year before Cavendish died. Two months before he died, Cavendish told Blagden that he had “doubts about some part of Malus’s
In their few surviving letters, Henry and his brother Frederick
Frederick was known to be a soft touch. One of his last letters to Henry is about a young married man who was just getting started and needed £150 to pay off his upholsterer’s bill. Frederick asked Henry for this amount, since he did not have it, “confident [it] will do a great deal of good.”240 Henry obliged him. When Frederick exceeded his modest income, he asked Henry for money.241 He needed help with his taxes, which were then, as ever, baffling. Henry was sympathetic: “the printed forms sent both by the commissioners of Income & assessed taxes are intricate & not clearly expressed.”242 On his side, Frederick was mindful of his brother’s interests: “As I believe you attend a good deal to the observation of the barometer,” he sent Henry a careful account of his reading of the barometer that morning. Frederick was two years younger than Henry, and he outlived him by two years. The life span in this branch of the Cavendishes was long and remarkably constant: the three of them, Charles, Henry, and Frederick, lived to the age of seventy-eight and seventy-nine.
Up to the end Henry Cavendish was vigorous, physically and mentally
Because there was a famous contemporary surgeon and anatomist named John Hunter
From Blagden we learn of Cavendish’s next illness. Cavendish came faithfully to Banks’s open houses, so when he was absent one Sunday in 1804 Blagden made note of it.253 A few days later Blagden was informed that Cavendish was ill.254 This time he was attended by the physician Everard Home
When Cavendish had his rupture, Home told Blagden that the disorder began with a swelling of the legs: “as if old the first time,” Blagden wrote in his diary that day.258 Cavendish was ill on 16 and 17 February 1804, and Blagden went to see him on the 18th, on which day Cavendish made out his final will, though it seems he did not show it to Blagden.259 Either Home or Blagden, or both, evidently had an insight. Cavendish was seventy-two, and he had an intimation of death. On a day when the Royal Society Club met in 1807, Blagden recorded in his diary, “Spoke to Cav. about parallax of fixed stars; it seemed as if he began to forget.”260 Cavendish was perhaps a bit forgetful, but after a meeting of the Council of the Royal Society in 1809, eight months before he died, Blagden wrote that he “looked in excellent health.”
If Cavendish came to the few meetings of the Society for the Improvement of Animal Chemistry before his death, he would have been an interested party to the discussions. He had given considerable thought to plant and animal substances
The Society for the Improvement of Animal Chemistry
To the end Cavendish was fully active in the work of the Society, as shown by his agreement to superintend the construction of an apparatus for measuring the temperature at different depths of the sea. He did not have time to oversee the experiment.269 He attended Council
The several accounts of Cavendish’s
Home was certainly there, as we know from an entry in Blagden’s
We now pass to another, all-too-human emotion. Cavendish’s fortune was on everyone’s mind, including his physician Home’s; on the morning Cavendish died, Home had Cavendish’s servant give him the keys, with which he prowled through the house opening drawers, trunks, and cupboards looking for treasures, which he found and noted.276 In a few days word was out that no will
Apart from his brother, Henry had outlived his own generation of Cavendishes. In the next generation, there were seven prospective male heirs
The last five living male Cavendishes of the next-generation were Horatio
Grandson of Henry de Grey, duke of Kent, Henry Cavendish had three living male relatives of his own generation on the Grey side: John, second earl of Ashburnham
Henry Cavendish’s landed property was left to his brother, Frederick
The funeral procession
In his will, Henry Cavendish left £15,000 to Blagden
The scientific colleagues who gathered at Banks’s house in the weeks following Cavendish’s death had other concerns too. There was Cavendish’s
From the beginning, there was discussion of an edition of Cavendish’s published works, but what to do about his unpublished papers
We have now finished the search which your Lordship desired us to make, in the hope of finding, among the papers of the late Mr. Henry Cavendish, something which he had prepared & thought fit for printing. Our search has in this respect been fruitless; a result for which we are sorry, though we must confess that it was not unexpected to us; because we knew that Mr.Cavendish was always ready to publish whatever he had made out to his full satisfaction. There are some few small scraps, which are transcribed nearly fair, as if he had thought of communicating them to the R.S.: but as it is apparent that they have been laid by, in that state, for a considerable time, it is to be supposed that he afterwards discovered some weakness or imperfection in them, or that they had been anticipated in a manner of which he was not aware when he composed them; in short, that he had some good reason for not giving them to the public. In truth, Mr. Cavendish’s fame stands so high already in the scientific world, that no papers but of the most perfect kind could be expected to increase it, whilst it might be lowered by anything of an inferior nature.298
Blagden and his colleagues firmly recommended against including any of the unpublished papers in the proposed edition of Cavendish’s papers
Blagden, Banks, and others recognized the peril of trying to improve a reputation posthumously, but they were mistaken about the worth of Cavendish’s manuscripts. That could hardly have been otherwise, since the papers contained much that was original, and much more than the work of a few hours or a few days was required to appreciate this. Blagden
John Pollock (1977, 117–118); Standish Meacham (1964, 27–28); E.M. Forster (1956, 4–9, 26–63); R. de M. Rudolf (1927, 89–90); Michael Hennell (1958, 104–168).
John Gascoigne (1989, 254).
Hennell (1958, 42, 52–53, 143). Forster (1956, 35–36, 53).
Pollock (1977, 183–184). Hennell (1958, 241–242).
Meacham (1964, 65).
Ibid., 80. Hennell (1958, 215).
“Watching and Lighting Notes, Clapham,” 138.
George Wilson (1851, 180–182).
Untitled Clapham rector’s account book, 1791–1842, Lambeth Archives, P/C/26, p. 152.
“Bedford Square. James Fuller’s Account with the Exec. of Hen: Cavendish … Settled 30 August 1810,” Devon. Coll.
9 June 1768, Minutes of Council, Royal Society 5:314. George A. Foote (1970, 434).
David Philip Miller (1981, 9, 14–16, 19, 43–47). Hector Charles Cameron (1952, 209).
Timothy Holmes (1898, 46, 68).
Wilson (1851, 129).
Charles Blagden to Joseph Banks, 2 Feb. 1788. Charles Blagden to Henry Cavendish, 2 Feb. 1788; in Jungnickel and McCormmach (1999, 648–649).
Charles Blagden to William Watson, Jr., 5 Feb. 1788, draft, Blagden Letters, Royal Society 7:115.
Charles Blagden to Joseph Banks, 27 Mar. 1789, BL Add Mss 33272, pp. 56–57.
Joseph Banks to Charles Blagden, n.d. [after 28 Mar. 1789], draft, BL Add Mss 33272, p. 58.
“Remarks by Mr.Cavendish,” Blagden Collection, Royal Society, Misc. Notes, no. 65. Charles Blagden to Henry Cavendish, 12 and 26 Mar. 1790; in Jungnickel and McCormmach (1999, 675, 677). Among other assistance, Cavendish made available his father’s table of the expansion of water with heat. “From the Experiments of Lord Charles Cavendish, Communicated by Mr. Henry Cavendish. March 1790,” Blagden Collection, Royal Society, Misc. Notes, no. 99.
Charles Blagden to Joseph Banks, 28 Mar. 1789, BL Add Mss 33272, p. 59. Joseph Banks to Charles Blagden, 15 July 1789, Blagden Letters, Royal Society, B.39. Charles Blagden to Joseph Banks, 25 July 1789, draft, Blagden Collection, Royal Society, Misc. Matter – Unclassified. Joseph Banks to Charles Blagden, 31 July 1789, Blagden Letters, Royal Society, B.40.
Charles Blagden to Joseph Banks, 27, 28, 29 Mar. and 8 Apr. 1790; Joseph Banks to Charles Blagden, n.d., BL Add Mss 33272, pp. 73–74, 80.
Draft of a letter in the Blagden Collection, Royal Society, Misc. Notes, no. 224. Because of the similarity of content and wording to a letter from Blagden to Banks on 8 Apr. 1790, it is probably from around that time. Blagden’s comment that he “had not had any opportunity of being serviceable” might seem to rule out Cavendish.
Charles Blagden to John Blagden Hale, 13 Nov. 1789, draft, Blagden Papers, Yale, box 5, folder 49.
Wilson (1851, 169–170).
Blagden to Banks, 8 Apr. 1790.
Banks to Blagden, 27 Mar. 1790.
Henry Brougham (1845, 258).
Blagden to Banks, 8 Apr. 1790.
Charles Blagden to William Farr, 14 Nov. 1785, draft, Blagden Letterbook, Yale.
Charles Blagden to Françoise Delarouche, 1 Dec. 1786, draft, ibid.
Charles Blagden to Henry Cavendish, Aug. 1789, draft, Blagden Letters, Royal Society 7:794.
Charles Blagden to John Blagden Hale, 17 Sep. 1789; “An Inventory of Furniture. Taken September 3. 1789 at Dr Blagden’s House in Gower Street Appraised & Sold to Hill Esq.,” Gloucestershire Record Office, D 1086, F 155, 157. Charles Blagden to William Lewis, 15 Sep. 1789, draft, Blagden Letters, Royal Society 7:306. Charles Blagden to John Blagden Hale, 16 Sep. 1789, draft, ibid. 7:309. Charles Blagden to Henry Cavendish, 16 Sep. 1789; in Jungnickel and McCormmach (1999, 668–669).
25 May 1807, Charles Blagden Diary, Royal Society 5:73.
20 Nov. 1806, ibid. 5:12.
2 Feb. 1805, 12 Mar. 1807, ibid. 4:307 and 5:46.
Joseph Banks to Charles Blagden, 27 Apr. 1797, Blagden Letters, Royal Society, B.44.
Charles Blagden to Joseph Banks, 27 Apr. 1797, BL Add Mss 33272, 158–159.
He resigned on 30 Nov. 1797. The draft letter of resignation, undated, with no address, begins: “The inflammation of my eyes ….” Blagden Collection, Royal Society, Misc. Matter – Unclassified.
Thomas Thomson (1830–1831, 1:338). Wilson (1851, 129). Charles Blagden to Henry Temple, Lord Palmerston, 8 Oct. 1790, draft, Blagden Papers, Yale, box 63/43.
Charles Blagden to John Blagden Hale, 13 Nov. 1789.
Charles Blagden to Joseph Banks, 1 Apr. 1802, BL Add Mss 33272, 172–173.
Thomas Knowlton to John Ellis, Oct. 1770, in James Edward Smith (1821, 2:79).
John Pearson (1983, 122–123). Francis Bickley (1911, 202).
Hugh Stokes (1917, 283–288).
Mary Robinson (n.d., 301).
Bickley (1911, 241).
Georgiana Cavendish, duchess of Devonshire to Countess Spencer, 11 Jan. 1783, Devon. Coll.
Charles Blagden to Henry Temple, Lord Palmerston, 21 Feb. 1794, draft, Osborn Collection, Yale, box 63/43.
Charles Blagden to Georgiana Cavendish, duchess of Devonshire, 4 Jan. and 6 Mar. 1794, Devon. Coll.
Georgiana Cavendish, duchess of Devonshire to Charles Blagden, 4 Mar. 1794, Blagden Letters, Royal Society, D.61.
G. De Beer (1950, 76, 80, 83).
Once when she called on Cavendish, his servant told her he was unwell, and she asked Blagden to find out how he was. Charles Blagden to Joseph Banks, 11 Aug. 1795, BL Add Mss 33272, 143. It was not an excuse: Blagden called on Cavendish later that month and found him “decaying: his forehead healing not kindly.” 27 Aug. 1795, Charles Blagden Diary, Royal Society 3:67.
1 Sep. 1794, Charles Blagden Diary, Royal Society 3:14. Cavendish may have acted as a tutor to the duchess: when Blagden arrived at her house, he found “Mr. Cav. there; saw none had notes.” The duchess proposed that Cavendish “shew extracts from Js de Physique.” On 27 Nov. 1794, Blagden again came across Cavendish at the duchess’s: “Met Mr. Cav. there: pleasant talk.” Ibid., 33(back).
Herschel observed what he regarded as a volvanic eruption on the moon, shining with a fiery light, and he observed two “extinct” volcanoes as well; he came to his conclusion about what he saw “by analogy, or with the eye of reason.” With a telescope, Cavendish and Blagden observed the unusual light in the dark area of the moon where Herschel thought he had located a big volcano. William Herschel (1787). Charles Blagden to Mrs. Grey, 14 June 1787, draft, Blagden Letterbook, Royal Society 7:324.
Charles Blagden to John Michell, 31 Oct. 1786, draft; in McCormmach (2012, 413).
Michael A. Hoskin (1963, 17–18, 62–64). “Herschel, Sir William (1738–1822),” DNB, 1st ed. 9:719–725.
Playfair quoted in Geikie (1917, 160).
Playfair, quoted ibid., 159. In the 1780s Aubert’s astronomical establishment was “except that of Count Brűhl […] the only well-equipped private establishment of the kind in England.” “Aubert, Alexander (1730–1805),” DNB, 1st ed. 1:715. “Brűhl, John Maurice, Count of (1736–1809),” ibid. 3:141.
William Herschel to Alexander Aubert, 9 Jan. 1782, copy, Royal Astronomical Society, Herschel W1/1, 21–24; published in Constance A. Lubbock (1933, 102–103).
Henry Lyons (1944, 197).
Ibid. Edward Smith (1911, 56–57).
Over the course of his long activity in astronomy, he published three papers on the transit of Venus in 1769, a new method of finding time by equal altitudes in 1776, and meteors in 1783, all brief and all appearing in the Philosophical Transactions.
In a bundle of papers dealing with Cavendish’s Clapham Common property are extracts from Aubert’s and Aubert’s heirs’ wills. They were assembled to transfer the property to the duke of Devonshire. Devon. Coll., L/38/78.
Maskelyne’s obituary, Gentleman’s Magazine 81:1 (1811): 197, 672. Playfair (1822, 1:lxxix; Appendix, No. 1, “Journal”). “Maskelyne, Nevil (1732–1811),” DNB, 1st ed. 12:1299–1301.
14 Aug. 1760, Minute Book of the Royal Society Club, Royal Society, 4.
Material on Michell’s life, in McCormmach (2012).
The focal length has been stated variously as 120, 122, 123, and 126 feet, as has its aperture, , inches. R.A. Sampson and A.E. Conrady (1928–1929, 289, 291).
The Journal Book of the Royal Society said that Christiaan Huygens made the telescopes: 7 Jan. 1742, JB 13:4334. Sampson and Conrady give the reason for attributing them instead to the brother, Constatine. “Three Huygens Lenses” (Sampson and Conrady 1928–1929, 292). When Cavendish returned the telescopes he included his apparatus. Ibid., 289.
Any increase in magnification comes at a high price, for the length of a telescope increases faster than the magnification: to double the magnification, the length has to be quadrupled; to triple it, the length has to be increased ninefold. The 123-foot Huygens telescope has a magnification of 218. William Kitchener (1825, 22). The very slight curvature of the long focal length lens greatly reduces spherical aberration, and chromatic aberration is practically eliminated for the following reason. The telescope consists of two lenses, neither of which is achromatic, but if the two lenses are made of glass of the same dispersion and the telescope is focused at infinitely distant objects such as stars, the angular magnification for any given color depends only on the curvature of the lenses and not on the refractive index. The workmanship on the Huygens lenses was of high quality, but not the glass, which compares poorly with the cheapest bottle or window glass. The tangle of fine veins in the glass made the refraction irregular. The glass available to Huygens resulted in a poor definition of images, as Cavendish no doubt determined. Sampson and Conrady (1928–1929, 298–299).
Newton’s other early reflecting telescopes had spherical mirrors, which were subject to spherical aberration. Astronomers knew that to achieve sharp images, the mirrors needed to be parabolic, but they were hard to make. Hadley’s first telescope with a mirror of 6 inches diameter and a length of 6 feet worked almost as well as Huygens’s 123-foot aerial telescope.
Huygens explained the working of the aerial telescope. The observer stood resting his arms on a light frame or hurdle and holding the eyepiece (concentric, adjustable metal tubes containing the eye-glass) by the handle. A cord connected it to a short board on which the object glass was mounted at one end and a counterpoise at the other. By tension on the cord the observer could bring the two lenses into parallel. Christiaan Huygens (1684). Smith (1952, 354). Sampson and Conrady (1928–1929, 298).
A.J. Meadows (1970, 307).
Smith (1738, 2:354, 440). R.S. Rigaud (1832, ix, lx, lxxxiv). 20 June 1728, JB, Royal Society 13:237. 10 and 29 Aug. 1748, Minutes of Council, Royal Society 4:5–8. King (1955, 63). Charles Yorke to Philip Yorke, 23 Aug. 1748, BL Add Mss 35360, f. 185. Thomas Birch to Philip Yorke, 18 Aug. 1748, BL Add Mss 35, 397.
Catherine Talbot to Elizabeth Carter, 10 Oct. 1748, in Carter (1809, 1:293–294).
10 Dec. 1778, Minutes of Council, Royal Society 5:369.
The computations for the mast are in Cavendish Mss, Misc. Robert Smith (1738, 2:355).
Burgess (1929, 57).
Alexander Aubert to William Herschel, 23 Mar. 1786, Royal Astronomical Society, Mss Herschel W 1/13, A23.
Charles Blagden to C.L. Berthollet, draft, 5 June 1786, Blagden Letterbook, Royal Society 7:2.
Charles Blagden to Benjamin Thompson, draft, 7 July 1786, Blagden Letterbook, Royal Society 7.
This is what Dolland told Kitchener (1825, 22).
Out of historical curiosity, the astronomer W.H. Smyth considered setting up the telescope again, around 1835: “I was so puzzled to know how they contrived to get the eye and object-glasses of these unwieldy machines married, or brought parallel to each other for perfect vision, and so desirous of comparing the performance of one of them, that I was about to ask the Royal Society’s permission to erect the aerial 123-foot telescope in their possession. The trouble, however, promised to be so much greater than the object appeared to justify, that I laid the project aside.” Quoted in Weld (1848, 1:331). In 1929 Sampson and Conrady examined the two Huygens lenses of longer focal lengths. They used an interferometer to determine the focal lengths and again to determine the radii of curvature, since the extreme shallowness of curvature of the long-focal-length lenses precluded the use of a spherometer. Sampson and Conrady (1928–1929, 294–297).
Supported by Cavendish’s computations, Hornsby thought that Herschel’s observations were in error. Herschel thought otherwise. Thomas Hornsby to William Herschel, 26 Feb. 1782; William Herschel, “Memorandum for Mr.Cavendish,” in Lubbock (1933, 106–107).
Charles Blagden to Claude Louis Berthollet and to Benjamin Thompson, 4 Aug. 1786, draft, and to Caroline Herschel, 5 Aug. 1786, draft, Blagden Letters, Royal Society 7:18–20. Caroline Herschel (1786).
Henry Cavendish, “Miss Herschels Comet,” Cavendish Mss VIII, 37. This was the 1788 comet.
Charles C. Gillispie (1978, 309–310).
Henry Cavendish, “Comet, 1532”; “In Order to Compute the Return of a Comet,” Cavendish Mss VIII, 38, 39. Nevil Maskelyne (1786, 429). Charles Blagden to Mrs. Grey, 5 Oct. 1786, draft, Blagden Letters, Royal Society 7:39.
Nevil Maskelyne, “Remarks on Mr. Cavendish Paper on Finding the Orbit of a Comet,” 16 Apr. 1789, enclosed in Henry Cavendish, “Method of Finding Comets Orbit Fair,” Cavendish Mss VIII, 43; in Jungnickel and McCormmach (1999, 662).
Henry Cavendish to Nevil Maskelyne, [after 16 to April 1789], in Jungnickel and McCormmach (1999, 664). Henry Cavendish, “On the Alteration Produced in Comets Orbit by Attraction of ⨁,” Cavendish Mss VIII, 52; “Written for Person Thought of for Calculating Perturbation of Expected Comet,” ibid., 53.
Henry Cavendish, “To Find the Alterat. Produced in the Elements of a Planetary Orbit by a Small Alteration in Its Velocity & Direction,” Cavendish Mss, Misc.
Henry Cavendish, “To Find Whether 2 Parabolic Orbits Can Be Drawn So as to Agree with Observation.” This concerns the question whether or not more than one parabolic orbit can be drawn through three points and other matters pertaining to comets. It is written partly on paper carrying the watermark 1797, which he was still using in 1799. Cavendish Mss VIII, 40. Another paper written partly on paper carrying the watermark 1797, but also partly on paper with watermarks 1802 and 1804, which may mean that it was written at different times, is Henry Cavendish, “Boscovics Method of Finding the Orbit of a Comet,” Cavendish Mss VIII, 50. The next paper is undated, but since Cavendish drew on Boscovich for his study of the comet of 1799, it may belong to that time: “Example of Computing Orbit on Bosc. Principle without Graphical Operat.,” Ibid. VIII, 42.
Henry Cavendish, “Comet of 1799 Computed by the Table for Boscovic’s Sagitta”; “Comet of 1799”; “Computation of Comet of 1799 by Fluxional Process,” Cavendish Mss VIII, 44, 46, 47.
Henry Cavendish, “La Places Method,” Cavendish Mss VIII, 41. Henry Cavendish to Nevil Maskelyne, [Oct. 1799], draft, Cavendish Mss VIII, 46; partially reproduced in Jungnickel and McCormmach (1999, 720).
A. Wolf (1961, 159–160).
“Mr. Ludlam’s Acct of Mr. Harris Ms.,” Cavendish Mss V, 3.
Examples are: Henry Cavendish, “On the Aberration in Reflecting Telescope Used in Herschels Manner”; “On the Aberration of Rays Passing through Spherical Lens,” Cavendish Mss V, 10, 11.
C.S. Hastings (1891, 344–345). H.C. King (1948).
Charles Blagden to M.A. Pictet, 9 Apr. 1789, Blagden Letters, Royal Society 7:223. We assume that Cavendish weighed the glass after it was ground into a prism, but it could have been before. See next footnote.
Another reason for thinking the glass is the same as the one Blagden brought home is that Cavendish’s drawing of a compound prism made up of a prism of Swiss glass and a prism of flint glass shows the former as the smaller of the two prisms, in agreement with the smallness of the prism made from Blagden’s glass.
Henry Cavendish, “On Rays of Different Colours Transmitted through Prisms of Different Materials,” Cavendish Mss V, 4.
Harold Falck-Ytter (1983, 57, 60).
Henry Cavendish (1790); Thorpe (1921, 67–68).
Henry Cavendish (1792).
William Marsden (1790). 17 May 1787, Minute Book of the Royal Society Club, Royal Society, 8. In that year Marsden was elected member of the Club.
Davis asked Banks to show a paper of his to Cavendish, initiating the connection. Samuel Davis to Joseph Banks, 10 Mar. 1791, Banks Correspondence, Royal Botanical Gardens, Kew, l.38.
28 June 1792, Certificates, Royal Society 5.
Cavendish (1792, 237, 242).
Ibid., 238, 242–243, 245.
The extract from Cavendish’s letter was published at the end of Mendoza y Rios (1797): “Addition. Contenant une methode pour reduire les distances lunaires,” 119–22; Henry Cavendish (1797, 246–248).
Allan Chapman (1993, 209).
John Bird (1767, 2, 11, 13).
E.G.R. Taylor (1966, 244).
Jesse Ramsden (1777, 1).
31 July and 25 Sep. 1783, Minutes of Council, Royal Society 7:143, 146.
These were Charles Blagden’s words, reporting what Ramsden said. Letter to Joseph Banks, 23 Sep. 1790, BL Add Mss 33272, pp. 89–90.
David Baxandall (1923–1924, 135).
John Smeaton (1814, 170, 186).
Baxandall (1923–1924, 136).
Meeting of the committee on 22 Jan. and report of the meeting of the Council on 28 May 1807, “Visitations of Greenwich Observatory 1763 to 1815,” Royal Society, Ms. 600, XIV.d.11, ff. 59–62.
A.W. Skempton and Joyce Brown (1973, 246). In 1823 the instrument was examined for accuracy to “correct rumours harmful to Mr. Troughton.” Taylor (1966, 289).
14 May 1807, Charles Blagden Diary, Royal Society 5:69.
22, 23 Jan. 1807, Charles Blagden Diary, ibid. 5:29.
28 May 1807, Minutes of Council, Royal Society 7:503.
Skempton and Brown (1973, 246).
Troughton (1809, 105–106).
John Pond (1806, 421).
William Lax (1809, 232–233).
Henry Cavendish (1809, 287)
The auction catalog of Cavendish’s instruments lists five beam compasses, items 22–24. Catalogue of Sundry Very Curious and Valuable Mathematical, Philosophical, and Optical Instruments.
Horace Darwin, in Thorpe (1921, 74).
Cavendish (1809, 293).
Troughton (1809, 140).
James Gerald Crowther (1962). His discussion of Cavendish is on 272–275.
Hugo Lidbetter offers a psychological explanation for why Cavendish held back from publication. He thinks that Cavendish was autistic, for which reason he did not spontaneously share his interests and achievements with others. If Cavendish was autistic, this is a credible general reason for Cavendish’s relative indifference to publication. Lidbetter misreads what Christa Jungnickel and I say in our Cavendish biography, where he says that we explain why Cavendish held back from publication by his “views on the inadequacy of language.” That is not what we say, as he should know, since he quotes the relevant passage from our book earlier in his article. In a discussion of Cavendish’s taciturnity we say that words, as used in normal speech, do not adequately represent Cavendish’s world; for that mathematics and quantities are needed. Publications are, of course, exactly where mathematics and quantities are proper and necessary. We offer a suggestion arising from his work that refers to his habits of speech, not of publication. Jungnickel and McCormmach (1999, 370). Hugo Lidbetter (2009, 784). I thank Steve Silberman for the reference to Lidbetter’s article.
William Heberden, “Upon Composition, Authors, and Their Works in General, Either of Genius or Science,” quoted in Humphry Rolleston (1933, 417–418).
Laurence Sterne (1951, 165–166).
Unsigned memorandum by Joseph Banks to Charles Jenkinson, Lord Liverpool, , in Liverpool Papers, BL Add Mss 38422, vol. 233, ff. 320–324, on 321–322.
John Craig (1953, 260–262).
Ibid., 268–269. Charles Jenkinson, Lord Liverpool to Joseph Banks, 10 May 1798, BM(NH), DTC 3:279–280.
Henry Cavendish to Joseph Banks, 23 July and 6 Aug. 1798; in Jungnickel and McCormmach (1999, 708–709). Charles Jenkinson, Lord Liverpool to Joseph Banks, 13 Feb. 1799, BM(NH), DTC 3:195–196. On Cavendish’s urging, a report was also given by A. Robertson, an Oxford mathematician who did research on coinage; Robertson’s report was delivered and read by Cavendish, to whom Liverpool gave his thanks on 12 Apr. 1799; in Jungnickel and McCormmach (1999, 714).
Charles Jenkinson, Lord Liverpool to Joseph Banks, 7 July 1798, BM(NH), DTC 3:19–20.
Charles Hatchett to Joseph Banks, 14 Mar. 1800, BL Add Mss 33980, f. 225.
J.C. Chaston (1974, 111).
Ibid., 112. In the practice at the time, the best compromise of hardness and color was obtained by an amalgam 1/12th to 1/13th of alloy; pure silver and pure gold were found unsuitable. Joseph Banks to Lord Liverpool, 11 May 1801, BL Add Mss 38424, ff. 158–59. Craig (1953, 269).
Charles Hatchett (1803, 193).
Chaston (1974, 112).
Cavendish to the privy council committee for coins, prefacing Charles Hatchett’s report, 28 April 1801; in Jungnickel and McCormmach (1999, 724). Joseph Banks to Charles Jenkinson, Lord Liverpool, 11 May 1801, BL Add Mss 38424, ff. 158–59. The report addressed to Lord Liverpool and the select committee for coins was signed by Hatchett, 28 Apr. 1801, BL Add Mss 38426. The title of the report of the experiments, which begins on f. 25, is “Experiments and Observations on the Various Alloys, on the Specific Gravity, and on the Comparative Wear of Gold.”
Henry Cavendish to Charles Hatchett, 15 Oct. 1802; in Jungnickel and McCormmach (1999, 726). This letter was enclosed in a letter to Banks by Hatchett, in which Hatchett said that Lord Liverpool was satisfied with Cavendish’s opinion on the publishable nature of the material. Charles Hatchett to Joseph Banks, 24 Oct. 1802. Hatchett and Cavendish’s desire to see the experiments published was first put to Lord Liverpool by Joseph Banks on 21 Aug. 1801, BL Add Mss 38424, ff. 160–161.
Banks to Lord Liverpool, 21 Aug. 1801.
Hatchett (1803, 45).
Henry Cavendish to Charles Jenkinson, Lord Liverpool, 13 July ; in Jungnickel and McCormmach (1999, 704).
Charles Jenkinson, Lord Liverpool (1805, 8–9). “Heads of So Much of Lord Liverpool’s Speech,” f. 402.
John Craig (1964, 161–162).
K.D.C. Vernon (1963). W.J. Sparrow (1964, 109–110). Sanborn C. Brown (1976).
Cavendish became a proprietor on 10 Feb. 1800. The managers at their meeting on 17 Feb. said that the Royal Institution was “now established on a Basis so firm & respectable, that no Doubt can be entertained of its Success.” Royal Institution of Great Britain (1971).
He was elected at the annual meeting of proprietors on 1 May 1800. Entry for 5 May 1800, Minutes of the Meetings of Managers, Royal Institution 2:70.
31 March 1800, Minutes of the Meetings of Managers, Royal Institution Archive 2:39–41. The other members of the committee were James Rennell, Joseph Planta, E. Whitaker Gray, J. Vince, and William Farish. The last two were professors of experimental philosophy and of chemistry at Cambridge. Maskelyne was appointed but declined because he was too busy.
2 Feb. 1801, Minutes of the Meetings of Managers, Royal Institution 2:126–127. Vernon (1963, 18).
Vernon (1963, 19, 22).
26 May 1803, Minutes of the Meetings of Managers, Royal Institution 3:137–138.
5 Sep. 1803, Ibid. 3:151.
The motion seconded by Cavendish requested the Royal Society to inform the Royal Institution of those papers read at its meetings that were suitable for the Royal Institution’s journal. It also required that an earlier resolution of 31 March 1800 be communicated to the Royal Society concerning the duty of the scientific committee to communicate discoveries to the Royal Society. 5 Apr. 1802, Minutes of the Meetings of the Managers, Royal Institution 2:260.
Thomas Young to Henry Cavendish, 3 Sep. 1801, enclosed in a paper, “On the Shape of the Teeth in Rack Work”; in Jungnickel and McCormmach (1999, 725). Young acknowledged Cavendish for the demonstration. Thomas Young (1802, paragraph 179; 1807, 2:308). Joseph Larmor’s comment in Cavendish, Sci. Pap. 2:410.
Vernon (1963, 27).
John Davy (1836, 222).
Benjamin Thompson, Count Rumford (1798); in Thompson (1870–1875, 1:490); Thompson (1799); ibid. 2:14.
Davy was working in Thomas Beddoes’s Pneumatic Institution at the time. Beddoes included Davy’s “Essay on Heat, Light, and on the Combinations of Light” in his collection Contributions to Physical and Medical Knowledge, Principally from the West of England (Bristol, 1799), 3–147. David M. Knight (1971, 599).
George E. Ellis (1871, 486).
Garnett took up heat in his chemical lectures rather than in his lectures on natural philosophy. He accepted the new chemistry of Lavoisier’s together with the new nomenclature: the phlogiston theory, he said, involved its supporters in “continual absurdities, and “the ancient language of chemistry was “very barbarous,” “conveying false ideas.” Following the new nomenclature, he called heat “caloric,” whether it is an imponderable fluid or motion, but as a former student of Black’s he talked about caloric in the way Black talked about heat, as if it were a fluid. When a quantity of heat becomes latent, it “becomes absorbed.” Bodies become elastic fluids through their “combination” with caloric. Caloric occurs either in a “combined or free state.” Outlines of a Course of Lectures on Chemistry: Delivered at the Royal Institution of Great Britain, 1801 (1801a, 16, 36, 39, 45, 60, 66). He published at the same time Outlines of a Course of Lectures on Natural and Experimental Philosophy, Delivered at the Royal Institution of Great Britain, 1801 (1801b). On his studies at Edinburgh, “The Life of the Author” (1804, vi–vii).
G.N. Cantor has noted the agreement on heat between Rumford, Davy, and Young, in “Thomas Young’s Lectures at the Royal Institution,” (1970, 90). In contrast to Garnett’s implied preference for the fluid theory, Young in his lectures at the Royal Institution reasoned by an analogy with the vibrations of sound that heat is the vibrations of the parts of bodies. Young, Course of Lectures on Natural Philosophy 1:148–149, 656. Davy wrote in 1799, “It has then been experimentally demonstrated that caloric, or the matter of heat, does not exist” and that heat is a “peculiar motion, probably a vibration, of the corpuscles of bodies.” (
Humphry Davy to Davies Gilbert, 8 Mar. 1801, in John Ayrton Paris (1831, 78).
Royal Institution of Great Britain, Minutes of Managers’ Meetings 1799–1900 5:47, 62, 126, 160.
Sparrow (1964, 110, 117).
Three years after Cavendish’s death, in 1813, Davy received from Faraday a copy of the notes he took of Davy’s lectures at the Royal Institution, the beginning of Faraday’s long association with the Institution.
The Royal Academy of Sciences, founded in 1699, was abolished together with all academies in 1793. In 1795, the National Institute of Sciences and Arts was established, which brought together the old academies. The Institute of France was established in 1796, containing the Academy of Sciences, no longer “Royal.”
Benjamin Thompson to Joseph Banks, 22 Nov. 1801, BL Add Mss 8099.
Charles Blagden to Joseph Banks, 19 June 1802, BM(NH), DTC 3:170–174.
Charles Blagden to Joseph Banks, 15 Oct. 1802, BL Add Mss 33272, pp. 204–205.
Charles Blagden to Joseph Banks, 26 Nov. and 6 Dec. 1802, ibid., pp. 210–213.
Charles Blagden to Joseph Banks, 29 Jan. 1803, Fitzwilliam Museum Library, Perceval H205.
Charles Blagden to Joseph Banks, 1 Feb. 1803, ibid., H206.
Georges Cuvier (1961, 237).
J.B. Biot (1813, 233).
“Cavendish (Henri),” in Arnault (1827, col. 294). “Cavendish (Henri),” in Hoefer (1855, 294). “Cavendish, Henry,” in J.C. Poggendorff (1863, 1:406).
John Aikin and William Johnston (1814, 283–285).
Thomas Thomson (1830–1831, 1:336–337).
Wilson (1851, 159).
D. Gautier to Charles Blagden, 30 Apr. 1811; Charles Blagden to D. Gautier, 20 Apr. 1812, Blagden Letters, Royal Society, G11, G11a. There would seem to be a problem with what Blagden says. Cuvier’s publication is dated 1812, and Biot’s publication above appears in a volume of the encyclopedia for the year 1813. On the face of it, Cuvier could not have copied Biot. However, Blagden’s letter pointing out Biot’s errors was written in 1812, the year before the volume of the encyclopedia. In it Blagden does not refer to an encyclopedia but to a “paper” published by Biot several years before. This paper I am unfamiliar with.
Wilson (1851, 160).
Alice Clare Carter (1968, 2–9). John Carswell (1993, 8, 12, 18–20).
Eugen von Philippovich (1911, 135). John Clapham (1945, 1:77, 97–98). Carter (1968, 10).
In literal translation, Biot’s epigram is wordier: Cavendish was “the richest of all the learned and probably also the most learned of all the rich.” Biot (1813, 273).
“Cavendish, Henry,” Encyclopaedia Britannica, 9th ed., vol. 5 (New York, 1878), 271–272, on 271.
He had no money in Consolidated 3% Annuities and Bank Stock. It is possible that he had a small investment in other issues.
The Elizabeth Cavendish inheritance of stocks and mortgages was legally transferred to Henry Cavendish after his father’s death. Lord Camden who was named with Lord Charles executor of Elizabeth Cavendish’s will agreed to transfer to Henry Cavendish the £75,000 in 3% annuities and the £22,100 in reduced annuities together with mortgages worth just under £50,000. “Lord Camden and the Honourable Henry Cavendish. Assignment and Deed of Indemnity, 31 Dec. 1783, Devon. Coll., 88/66.
Bank Stock 1783–1798, Bank of England Archive, No. 59, p. 389.
Reduced 3% Annuities, Bank of England Archive, Supplement Ledger 1781–1785, p. 10614.
Ibid., Ledger 1785–1793, p. 1505.
Ibid., p. 2242.
Ibid., Ledger 1793–1801, p. 1727.
Ibid., Ledger 1801–1807, p. 1801.
Ibid., p. 1937.
Ibid., Ledger 1807–1818, pp. 4449–4450.
Consolidated £ 3%, Bank of England Archive, 1782–1788, p. 3854.
Ibid., p. 3927.
Ibid., 1788–1792, p. 8000.
Ibid., 1792–1798, p. 8730.
Ibid., 1799–1804 (part 1), p. 8001.
Ibid., 1804–1812, p. 8001.
New South Sea Annuities, Bank of England Archive, 1776–1793, vol. 154, p. 65.
Clapham (1945, 2:39–40, 46).
“The Personal Property of the Hon. Henry Cavendish 24 February 1810,” Devon. Coll., 114/74. The evaluation was from Messrs Snow & Co. The family obituary gave different figures for Cavendish’s wealth: Cavendish “died worth 1,175,000l in different public funds, the value of which is estimated at 700,000l.” This information was given to Wilson by a member of the family. Wilson quotes the above sentence, except that two digits are reversed: 1,157,000l. Wilson (1851, 176). The family obituary says that “50,000l, also were in the hands of his bankers,” and Wilson repeats this. The discrepancy between the family’s account of Cavendish’s worth and what the bank documents say may have to do with the lapse between Cavendish’s death and the time his funds were distributed to his heirs. The discrepancy in any case is not large, and the point is made that Cavendish had a great deal of money invested in funds at the time of his death.
The family obituary says that at his death Cavendish had “freehold property about 8,000l. a year and canal and other personal property.” Wilson quotes from the obituary (1851, 176).
L.B. Namier (1929, 164).
Wilson (1851, 175).
Bundle of receipts for purchases of annuities, Devon. Coll., 86/comp. 3.
“1790–1816. Accs. & Receipts. Case & Opinions,” ibid.
Correspondence from Cavendish’s bankers, ibid.
Wilson (1851, 184–185).
Biot (1813, 273). Wilson (1851, 180–181). Privately, Newton held a Unitarian view.
R. de M. Rudolph (1927, 89).
Resolution Agreed to by the Inhabitants of Clapham for the Better Observance of the Lord’s Day, 1798.
From Lord Burlington, in Wilson (1851, 181).
19 Feb. 1807, Charles Blagden Diary, Royal Society 5:39.
Henry Cavendish (1751).
22 Feb. 1798, Minutes of Council, Royal Society 7:353.
26 Mar. 1804, Charles Blagden Diary, Royal Society 5:214.
16 Feb. 1809, ibid. 5:286.
3 Dec. 1809, ibid. 5:396(back).
Charles Blagden to Richard Chenevix, 1 May 1809, draft, Blagden Letters, Royal Society, C.35.
In January 1806, for example: “White Book No. 1,” 68.
Henry Cavendish to Frederick Cavendish, n.d., draft; Frederick Cavendish to Henry Cavendish, 10 Sep. 1809; in Russell McCormmach (2014, 260).
Henry Cavendish to Frederick Cavendish, n.d. , draft, Cavendish Mss, Misc.
“Memoirs of the Late Frederick Cavendish, Esquire,” Gentleman’s Magazine 82 (1812): 289–291.
Frederick Cavendish to Henry Cavendish, 5 and 12 Feb. 1810; in McCormmach (2014, 61).
Frederick Cavendish to Henry Cavendish, 9 Feb. 1810, ibid.
Frederick Cavendish to Henry Cavendish, 28 Oct. 1806; Henry Cavendish to Frederick Cavendish, n.d., draft, ibid., 259–260.
Charles Blagden to Henry Cavendish, 12 Mar. 1792, draft; in Jungnickel and McCormmach (1999, 689).
Charles Blagden to Henry Cavendish, 12 Mar. 1792, draft, ibid., 690.
Charles Blagden to Joseph Banks, 13 Mar. 1792, draft, Blagden Letters, Royal Society 7:626.
Alexander Dalrymple to Henry Cavendish, 16 Mar. 1792; in Jungnickel and McCormmach (1999, 691).
12 Jan. 1786, Certificates, Royal Society 5.
Blumenbach’s De generis humani varietate nativa was translated by T. Bendyshe and published together with a translation of Hunter’s inaugural dissertation, Disputatio inauguralis quaedam de Hominum varietatibus, et harum causis exponens …(Edinburgh, 1775) in The Anthropological Treatises of Johann Friedrich Blumenbach […] and the Inaugural Dissertation of John Hunter, MD On the Varieties of Man (London, 1865).
Hunter, On the Varieties of Man, 365–368, 378.
John Hunter (1788, 53, 58, 65). Charles Blagden to William Farr, 21 Jan. 1788, draft, Blagden Letters, Royal Society 7:107.
Hunter included the paper from the Philosophical Transactions as an appendix to the second edition of his Observations on the Diseases of the Army in Jamaica (1796). The first edition was in the same year as the paper, 1788.
Lise Wilkinson (1982, 235–236).
12 Feb. 1804, Charles Blagden Diary, Royal Society 4:201.
16 Feb. 1804, ibid. 4:202(back).
The Society for the Improvement of Medical and Chirurgical Knowledge, whose leading member was the “other” John Hunter. Wilkinson (1982, 234)
William LeFanu (1972).
In 1795 Blagden sent Cavendish a paper by Home. Evidently the paper contained Home’s account of what would have appeared in John Hunter’s Croonian Lecture if he had not died before he could give it. Everard Home (1794). Hunter believed that the cornea can adjust itself by its own internal actions to focus the eye at different distances. Cavendish, assisted by Blagden, performed an experiment to detect changes in the convexity of the cornea accompanying changes in the focus, using a divided object-glass micrometer. Entries for 8, 11, and 16 Nov. 1795, Charles Blagden Diary, Royal Society 3:75(back), 76, and 77(back).
17 Feb. 1804, Charles Blagden Diary, Royal Society 4:202(back), 203.
“Copy of the Will of Henry Cavendish Esq.,” In “Account of the Executor of Henry Cavendish Esq. as to Money in the Funds,” Devon. Coll., L/31/65.
4 June 1807, Charles Blagden Diary, Royal Society 5:76.
8 June 1809, ibid. 5:328(back).
Gwendoline Averly (1989, 26–29).
Gwendoline Averley (1986, 102, 108–109, 113).
27 Apr. 1809, Minutes of Council, Royal Society 7:527–31.
Benjamin Collins Brodie (1865, 88–92).
Everard Home (1809, 386).
James Lewis Macie (1791, 370, 384–385, 388).
23 Feb. 1805, Charles Blagden Diary, Royal Society 4:313.
Joseph Banks to William Scoresby, Jr., 8 Sep. 1810, copy, Whitby Literary and Philosophical Society.
John Barrow (1849, 153–154).
Heberden gave a prescription. 25 Feb. 1810, Charles Blagden Diary, Royal Society 5:426(back), 427. Home’s fee was £105, Heberden’s £21. Lord George Cavendish, “Mr.Cavendish’s Executorship Agenda,” Devon. Coll.
25 Feb. 1810, Charles Blagden Diary, Royal Society 5:426(back), 427.
4 Mar. 1810, ibid. 5:429(back), 430.
24 Feb. 1810, ibid. 5:426, 426(back).
8 March 1810, ibid. 5:431(back), 432.
Barrow (1849, 154–155).
1 Mar. 1810, Charles Blagden Diary, Royal Society 5:428(back).
1 and 2 Mar. 1810, ibid. 5:428 (back), 429.
17 Sep. 1809, ibid. 5:330.
Wilson (1851, 173).
Wilson said of Lord Bessborough that Cavendish “was not, I believe, a connexion of his.” He missed the family connection, though it was close. Wilson (1851, 190). 1 Sep. 1794, Charles Blagden Diary, Royal Society 3:14. J.M. Collinge (2016)
R.G. Thorne (2016b).
R.G. Thorne (2016a).
Lady Sarah Spencer quoted in Hugh Stokes (1917, 315, 350).
Letter from the fifth duke’s second wife, Elizabeth Foster, to Augustus Foster, 1 Mar. 1810, in Foster (1898, 345).
Quotation from the “Journal” kept by the duchess of Devonshire, in Dorothy Margaret Stuart (1955, 174).
Charles C. Gillispie (1959, 209).
Henry Cavendish, “Papers in Walnut Cabinet,” Cavendish Mss Misc.
W. Ware to John Heaton, 27 Feb. 1810, Devon. Coll. “Memoirs of the Late Frederick Cavendish,” 291.
Lord Bessborough to Charles Blagden, 7 Mar. 1810, Blagden Letters, Royal Society, B.149.
“Mr. Swift’s Bill for Expenses at the Funeral of Hen: Cavendish Esq.,” 29 Aug. 1810, Devon. Coll., L/114/74.
“Cavendish, Henry,” Encyclopaedia Britannica, 9th ed., 5:271.
8 Mar. 1810, Charles Blagden Diary, Royal Society 5:431(back), 432.
Brougham (1845, 1:258).
3 and 4 Mar. 1810, Charles Blagden Diary, Royal Society 5:429, 429(back), 430.
Wilson (1851, 475). A Catalogue of Sundry Very Curious and Valuable Mathematical, Philosophical, and Optical Instruments.
This discussion of Cavendish’s papers is taken from Russell McCormmach (1988, 37–38). The first mention of a proposed edition of Cavendish’s works appears in the entry for 8 Mar. 1810 of Blagden’s diary; other entries on this subject are on 10, 26, and 27 Mar. 5, 8–9, 11–12, and 26 Apr. and 24 May 1810, Charles Blagden Diary, Royal Society 5.
Charles Blagden to “My Lord” [George Augustus Henry Cavendish], n.d., draft, Blagden Collection, Royal Society, Misc. Matter – Unclassified.
Table of Contents
Part I: Lord Charles Cavendish
Part II: The Honorable Henry Cavendish
17 Last Years
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