Henry Cavendish

Henry Cavendish FRS (10 October 1731 – 24 February 1810) was a British scientist noted for his discovery of hydrogen or what he called "inflammable air". Cavendish is also known for the Cavendish experiment, his measurement of the Earth's density, and early research into electricity.

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Quotes

Young people must break machines to learn how to use them; get another made!
- when he was told that one of his valuable instruments was broken by a young man, as quoted in Biographical Memoir of Henry Cavendish, by Georges Cuvier, The Edinburgh New Philosophical Journal (1828), p. 222.

The Scientific Papers of the Honourable Henry Cavendish, F.R.S (1921)

Vol. 2 Chemical and Dynamical. Edited from the Published Papers, and the Cavendish Manuscripts in possession of His Grace The Duke of Devonshire, K.G., F.R.S. by Sir Edward Thorpe, F.R.S. with Contributions from Dr Charles Chree, Sir Frank Watson Dyson, Sir Archibald Geikie, Sir Joseph Larmor. Cambridge at the University Press.

Three Papers, containing Experiments on factitious Air (1766)

by the Hon Henry Cavendish, F.R.S., was read before the Royal Society on May 29, Nov. 6, and Nov. 13, 1766, and received May 12, 1766. It was published in the Philosophical Transactions (1766) Vol. 56, article XIX, p. 77-144.

By factitious air, I mean in general any kind of air which is contained any in other bodies in an unelastic state, and is produced from thence by art.

By fixed air, I mean that particular species of factitious air, which is separated from alcaline substances by solution in acids or by calcination and to which Dr. Black has given that name in his treatise on quicklime.

Experiments on Air By (1784)

By Henry Cavendish Esq F.R.S. & S.A. Article XIII, Read January 15, 1784, Philosophical Transactions Vol. 74, p. 161.

I think we must allow that dephlogisticated air is in reality nothing but dephlogisticated water, or water deprived of its phlogiston; or, in other words, that water consists of dephlogisticated air united to phlogiston; and that inflammable air is either pure phlogiston, as Dr. Priestley and Mr. Kirwan suppose [and as Cavendish formerly supposed], or else water united to phlogiston; since, according to this supposition, these two substances united together form pure water. On the other hand, if the first explanation be true, we must suppose that dephlogisticated air consists of water united to a little nitrous acid and deprived of its phlogiston; but still the nitrous acid in it must make only a very small part of the whole, as it is found, that the phlogisticated air, which it is converted into, is very small in comparison of the dephlogisticated air.
- pp. 171-172.

Quotes about Cavendish

He was the wealthiest of all scholars (savants) and probably also the most scholarly of all the wealthy.
- Jean-Baptiste Biot, Biographie Universelle Ancienne et Moderne, as quoted by John Maxson Stillman, The Story of Early Chemistry (1924)
- More succinctly, "wisest of the rich and the richest of the wise", as quoted in Jungnickel, Christa, and Russell McCormmach. 1999. Cavendish: The Experimental Life. Rev. ed. Lewisburg, Pa.: Bucknell University Press.

I never charged or thought of charging Mr. Cavendish with having obtained from Mr. Watt's paper his knowledge of the composition of water, and having knowingly borrowed it, however suspicious a case Mr. Harcourt's publication may seem to make. Both those great men, in my opinion, made the discovery apart from each other, and ignorant each of the other's doctrine. Mr. Cavendish was a man of the strictest integrity, and the most perfect sense of justice. His feelings were very far inferior to his principles. He was singularly callous to the ordinary calls of humanity, as there exist positive proofs sufficient to satisfy the polemical writer upon whose paper ['Eloge de M. Cavendish'] I have been commenting if he has any mind to see them. Nor do they rest on my assertion, for I never had any intercourse with him except in society. But the pursuits of a philosopher and the life of a recluse, which had so entirely hardened his heart, had not in the least degree impaired his sense of justice; and my own belief is, that he as entirely supposed himself to have alone made the discovery in question, as Sir Isaac Newton believed himself to be the sole discoverer of the nature of light, and the theory of the solar system.
- Henry Brougham "Note to the Lives of Cavendish, Watt, and Black, Published in the First Volume" Lives of Men of Letters who Fluorished in the Time of George III (1846) Vol. 2, p. 515. Brougham's statement refers to the controversy over the discovery that water is the composed of the gases, "Dephlogisticated air" (Oxygen) and "Inflammable air" (Hydrogen). Reference: Mr. Harcourt's publication.

It were to be wished, that this noble philosopher would communicate more of his experiments to the world, as he makes many, and with great accuracy.
- Benjamin Franklin, The Works of Benjamin Franklin; with Notes and a Life of the Author (1856) ed. Jared Sparks, Vol. V, p. 383.

The Life of the Hon^ble Henry Cavendish (1851)

, Including Abstracts of His More Important Papers, and a Critical Inquiry into the Claims of All the alleged Discoveres of the Composition of Water by George Wilson, pp. 185-186.

It only remains that I offer very briefly my own estimate of the character of the Philosopher. Morally it was a blank, and can be described only by a series of negations. He did not love; he did not hate; he did not hope; he did not fear; he did not worship as others do. He separated himself from his fellow men, and apparently from God. There was nothing earnest, enthusiastic, heroic, or chivalrous in his nature, and as little was there anything mean, grovelling, or ignoble. He was almost passionless.

All that needed for its apprehension, more than the pure intellect, or required the exercise of fancy, imagination, affection, or faith, was distasteful to Cavendish. An intellectual head thinking, a pair of wonderfully acute eyes observing, and a pair of very skilful hands experimenting or recording, are all that I realise in reading his memorials.

His brain seems to have been but a calculating engine; his eyes inlets of vision, not fountains of tears; his hands instruments of manipulation which never trembled with emotion, or were clasped together in adoration, thanksgiving, or despair; his heart only an anatomical organ, necessary for of the circulation of the blood.

Yet, if such a being, who reversed the maxim nihil humani me alienum puto [nothing human is foreign to me], cannot be loved, as little can he be abhorred or despised. He was, in spite of the atrophy or non development of many of the faculties which are found in those in whom the "elements are kindly mixed," as truly a genius as the mere poets, painters, and musicians, with small intellects, and hearts and large imaginations, to whom the world is so willing to bend the knee.

He is more to be wondered at than blamed.

Cavendish did not stand aloof from other men in a proud or supercilious spirit, refusing to count them his fellows. He felt himself separated from them by a great gulf, which neither they nor he could bridge over, and across which it was vain to stretch hands or exchange greetings. A sense of isolation from his brethren, made him shrink from their society and avoid their presence, but he did so as one conscious of an infirmity, not boasting of an excellence.

He was like a deaf mute sitting apart from a circle, whose looks and gestures show that they are uttering and listening to music and eloquence, in producing or welcoming which he can be no sharer. Wisely, therefore, he dwelt apart, and bidding the world farewell, took the self imposed vows of a Scientific Anchorite, and, like the Monks of old, shut himself up within his cell. It was a kingdom sufficient for him, and from its narrow window he saw as much of the Universe as he cared to see. It had a throne also, and from it he dispensed royal gifts to his brethren.

He was one of the unthanked benefactors of his race, who was patiently teaching and serving mankind, whilst they were shrinking from his coldness, or mocking his peculiarities.

He could not sing for them a sweet song, or create a "thing of beauty" which should be "a joy for ever," or touch their hearts, or fire their spirits, or deepen their reverence or their fervour. He was not a Poet, a Priest, or a Prophet, but only a cold, clear, Intelligence, raying down pure white light, which brightened everything on which it fell, but warmed nothing—a Star of at least the second, if not of the first magnitude, in the Intellectual Firmament.

The American Universal Cyclopædia (1882)

" Water" The American Universal Cyclopædia (1882) Vol. 15, pp. 275-276.

[A] prolonged and acrimonious controversy... was for many years carried on and is... hardly... settled regarding the respective claims of different philosophers to be the true discoverer of the nature and composition of water.

In the year 1781, Cavendish made a long and careful series of experiments... not published till Jan., 1784, when his celebrated... Experiments on Air was read to the royal society.

In the interval (June, 1783) his friend, Dr. Blagden, visited Paris, and on the authority of Cavendish, gave an account of the experiments proving the composition of water to Lavoisier...

[T]his delay between the discovery and the date of publication caused his claims to one of the most marvelous discoveries the world ever saw, to be contested by... James Watt and Lavoisier.

Cavendish's experiments consisted in exploding, in various proportions, mixtures of hydrogen and atmospheric air, and of hydrogen and oxygen, and finding as the result a liquid which proved to be pure water. (Priestley and his friend, Mr. [John] Warltire, had made similar experiments, and had noticed the deposition of moisture that followed the explosion, but failed to recognize it anything but the condensation of aqueous vapors in the gases.)

The general conclusion to which Cavendish came was, in his own words, "that water consists of dephlogisticated air united with phlogiston," and as dephlogisticated air was his term for oxygen, and phlogiston his term for hydrogen, this statement corresponds to the modern view of the nature of water introduced by Lavoisier.

As Lavoisier was from the first accused by the English chemists of having acted unfairly toward them, and as indeed his own claim only dates back to June 25, 1783, he may be dismissed from further consideration; and during the lives of the English claimants there were no public complaints on either side, although Watt, in private letters to his friends, hinted at Cavendish's incapacity and unfairness.

Hence then—at all events in this country—scientific men were startled when Arago... published in 1838 the eloge of Watt, which he had read as far back as Dec., 1834, in which he charged Cavendish with deceit and plagiarism, inasmuch as he was said to have learned the composition of water, not by experiments of his own, but by obtaining sight of a letter from Watt to Priestley. The battle now fairly began...

Cavendish (1996)

by Christa Jungnickel, ‎Russell McCormmach, pp. 146-147.

At the time Cavendish made his study of arsenic compounds, chemists still had not been able to "determine what it /arsenic/ really is, or to what class of bodies it belongs." ...[A]rsenic behaves as a metal in some states, and like a salt in other states. ...[L]ike every metallic calx, arsenic [could be] changed into a metallic form... "regulus of arsenic"... [by combining] with "phlogiston." ...[L]ike salts, arsenic is soluble in water. ...[N]either acidic nor alkaline, yet Macquer claimed, behaving as if it were an acid. ...In other ways ...arsenic differs from other... calces: it is volatile with a strong smell, it is fusible, it unites with metals and semimetals—the difference that Macquer and Cavendish picked up on—it decomposes nitre when distilled with it. From the standpoint of affinities... arsenic is exceptional too.
- Footnote: Caspar Neumann, Chemical Works, 140-141, 145. What Neumann, Macquer, Cavendish, and... contemporaries called "arsenic" is... arsenious oxide... a common by-product of roasting metallic ores. Another name... is "white arsenic," the calx of regulus of arsenic, the white, shiny semimetal.

Neutral salts, Cavendish's starting point... were... composed of acids and other substances, mostly alkalis, that were without acidity. Not long before, all of the known neutral salts could be listed in a table of twelve... the possible combinations of the four known acidic salts and the three known alkaline salts. Just as Cavendish began to work... the tidy, managable table... was fast expanding. The empirical field of salts was recognized as highly undeveloped...

Cavendish procured Macquer's neutral salt using Macquer's method of distilling arsenic with nitre, producing copious red fumes... leaving... a cake of neutral arsenical salt. He then tried... dissolving arsenic in spirit of nitre, then adding pearl ashes... to obtain neutral arsenical salt. ...[His] discovery: what combined with the alkali ...was ...a new acid, "arsenical acid" ...[T]his new acid had "all the properties of an acid... unless perhaps it should fail in respect of taste which I have thought not proper to try." This research was the high point of Cavendish's researches on arsenic.
- Pearl Ash. A variety of potassium carbonate. A Dictionary of Applied Chemistry (1913) by Sir Edward Thorpe, Vol. 4, P. 107.

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