600.) 
Papers on 
the earth’s 
attraction, . 
and theory 
of electri- 
city. 
(601.) 
Singular 
personal 
character- 
istics of Ca- 
vendish. 
Cuapr. VI., § 2.] 
truth. But it is needless to dwell upon these obser- 
vations, however original, because they were volun- 
tarily suppressed by the author, and have only re- 
cently been brought to light from his manuscripts. 
What he did publish in connection with this subject 
was a paper on the construction and graduation of 
meteorological instruments, especially thermometers, 
and others on the temperature at which mercury 
freezes, and on freezing mixtures. The former of 
these papers was, as might be expected, far in ad- 
vance of its age in the degree of exactness which was 
shown to be attainable in the construction of ther- 
mometers, and scarcely even now can it be considered 
as obsolete. The papers on freezing mercury finally 
corrected the exaggerated notion at first entertained 
of the extreme cold at which that metal becomes 
solid, and also contain valuable views on the sub- 
ject of congelation, and fixed the latent heat of water 
at 150°. He calls this, “ generation of heat*’ during 
liquefaction, objecting to Black’s term as relating 
“to an hypothesis, depending on the supposition that 
the heat of bodies is owing to their containing more 
or less of a substance, called the matter of heat ; and 
as I think Sir Isaac Newton’s opinion that heat con- 
sists in the internal motion of the particles of bodies 
much the most probable, I chose to use the expres- 
sion, heat is generated,’ 
Two of Cavendish’s most important researches re- 
fer to the attraction and density of the earth, and to the 
mathematical theory of electricity. The former (which, 
in principle, was derived from the Rev. John Michell) 
has been already analyzed in the chapter on Astro- 
nomy (art. 156). The latter will be more conve- 
niently referred to in our chapter on Electricity, 
Cavendish’s publications extended over the greater 
part of his active life, but those on chemistry and 
electricity, on which his fame principally depends, 
do not extend beyond the year 1775; the date of his 
paper on the density of the earth is 1798. He died 
24th February 1810, at the age of 79. He appears 
to have.exercised scarcely less influence by his general 
devotion to science, than by his specific discoveries, 
great and original as they were. In 1782, when 
Playfair met him incidentally in London, he de- 
scribed him as being generally looked up to as one 
possessed of talents confessedly superior, and as the 
only member of the Royal Society who then united 
the knowledge of mathematics, chemistry, and ex- 
perimental philosophy. The absolute devotion of 
his life to inquiries the most abstractly scientific, 
whilst he showed an entire indifference to the luxuries 
which his wealth might have commanded, and the 
social station to which his birth entitled him, could 
not fail to inspire respect for his character, as well 
as to obtain the homage of mankind for pursuits 
so dignified and so generally disregarded. Many 
HEAT.—CAVENDISH. 
931 
curious anecdotes are related of the annoyance which 
the inevitable accumulation of his unspent income 
occasioned, He no doubt would have distributed more 
liberally what he so little valued, but for the amount 
of time and inquiry which such a course must have 
compelled him to withdraw from his beloved pursuits. 
Some instances of his generosity are on record, and 
others, no doubt, will never come to light. M. Biot’s 
epigrammatic description of him will probably long 
remain applicable,—* I] était le plus riche de tous 
les savats, et probablement aussi le plus savant de 
tous les riches.” 
This isolation of interest was doubtless due, quite 
as much to a constitutionally morbid temperament, 
as toareal misanthropy. He avoided even the most 
casual intercourse with his fellow men, excepting only 
when it was likely to bear the immediate fruit of 
scientific information. He almost never visited his 
relatives, and his heir paid him a visit of a few minutes 
once a year; but he frequented regularly the social 
meetings of the Royal Society Club, and the evening 
reunions of Sir Joseph Banks. But he came, not to 
participate, but to increase his stores ; if he spoke, it 
seemed to be by inadvertence, and he was silenced 
by a question, or even by a look, ‘ A sense of iso- 
lation 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 ex- 
cellence. 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 = 
ducing or welcoming which he can be no sharer. . . 
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. . . . Such was he in life, 
a wonderful piece of intellectual clock-work, and as he 
lived by rule he died by it, predicting his death as if it 
had been the eclipse of some great luminary, . . . and 
counting the very moment when the shadow of the 
unseen world should enshroud him in its darkness.” 
I shall only add, that Cavendish was elected one 
of the eight Associates of the French Institute in 
1803. This is a distinction perhaps the highest, of 
a formal kind, to which a scientific man can aspire, 
and was given at a time when, as an Englishman, he 
must have felt it to be peculiarly honourable. 
The philosophical character of Cavendish resembled 
(602.) 
(603,) 
04.) 
in many respects that of Newton; and with but a slight yj. philo- 
modification of its secondary ingredients, he might sophical 
have been, perhaps, another Newton in experimental ‘h*r<ter- 
physics. His singular incommunicativeness, and the 
absence of a laudable ambition to perpetuate his name 
by the establishment of great theories, are perhaps 
the main reasons why his reputation, except in che- 
mistry, did not stand yet higher than we find it. 
1 By the Rev. W. Vernon Harcourt in British Association Report for 1839. Compare Wilson’s Life of Oavendish, p. 446. 
2 Phil. Trans. 1783. 
3 Wilson’s Life of Cavendish. 
