(635.) 
Different 
experi- 
ments. 
(636.) 
Cuar. VI., § 4.] 
well as to the material wealth of many districts, we 
are disposed to give Rumford a higher place than has 
generally been accorded to him. Had his excellent 
principles been universally carried out, some millions 
sterling would have been saved to every large state 
in Europe. Fontenelle characteristically says of a 
certain savant, who made experiments on nutrition, 
with a view to carry fasting to the utmost practicable 
extent, that his researches had the double aim of 
a place in heaven and in the academy. Cuvier, who 
tells the anecdote in his Eloge of Rumford, adds, 
that the latter had a truer claim to the questionable 
compliment. That science is surely not despicable 
by which a pound of wool, of fuel, or of food, can be 
made to go one-half farther than before in warming 
the naked and in feeding the hungry. 
All Rumford’s experiments were made with admir- 
able precision, and recorded with elaborate fidelity, 
and in the plainest language, Everything with him 
was reduced to weight and measure, and no pains 
were spared to attain the best results. His experi- 
ments on heat, and the properties of bodies in con- 
nection with it, are the most important. He first 
applied steam generally in warming fluids and to the 
culinary art. He maintained the paradox of the 
non-conducting power of liquids, which, though prac- 
tically true, appears not to be rigorously so. He 
contrived many ingenious instruments; but his ther- 
moscope, identical with Leslie’s differential thermo- 
meter, was probably of later invention, if not in 
some measure borrowed from it. In like manner his 
proofs of the maximum density point of water were 
unquestionably suggested by Dr Hope’s beautiful ex- 
periment, although this derives its meaning from the 
laws of convection, which Rumford first established. 
That water expands in bulk below the temperature 
Dr Hope on of 39° or 40° Fahr. until it freezes, is a fact which 
the maxi- 
mum den- 
had been asserted since the middle of the seventeenth 
HEAT.—RUMFORD—HOPE. 
941 
it,' show that he had excellent qualifications. Hope 
was first the colleague, then the successor of Black 
in the chair of chemistry in Edinburgh; and in his 
time probably the most popular teacher in Europe 
of that science. He died on the 13th June 1844, 
in the seventy-eighth year of his age. 
Rumford’s name will be ever connected with the (637.) 
progress of science in England by two circumstances ; Rumford 
, 
first, by the foundation of a perpetual medal and 
Prize—the 
Royal In- 
prize, in the gift of the Council of the Royal Society stitution. 
of London, for the reward of discoveries connected 
with Heat and Light; and secondly, by the estab- 
lishment, in 1800, of the Royal Institution in Lon- 
don, destined, primarily, for the promotion of original 
discovery, and, secondarily, for the diffusion of a taste 
for science amongst the educated classes. The plan 
was conceived with the sagacity which characterized 
Rumford, and its success has been greater than could 
have been anticipated. Davy was there brought into 
notice by Rumford himself, and furnished with the 
means of prosecuting his admirable experiments. 
He and Mr Faraday have given to that institution 
its just celebrity with little intermission for half a 
century. 
Rumford spent his later years in Paris, where he 
died in 1814. The estimation in which he was then Rumford’s 
last years 
and death. 
held may be judged of from the fact, that he was 
one of the eight foreign associates of the Academy 
of Sciences. He was very capable of having done 
more for science; the versatility of his talents, the 
accidents of his early life, and the strong hold which 
principles of philanthropy and public utility always 
exerted over him, account for the absence of more 
sustained and erudite researches. But in those very 
particulars he deserves to be cited as a practical phi- 
losopher, as to many things in advance of his age, 
and a benefactor both to science and to mankind.* 
(638.) 
sity point century. But for 150 years its great improbability, 
of water. and the unquestionable uncertainty introduced into 
the result by the irregular expansion of the contain- 
ing vessel or glass of the thermometer, enabled scep- 
tics in every generation to withhold their assent. Per- 
haps the last who doubted was the illustrious Dalton. 
He allowed himself however to be convinced by Dr 
Hope’s experiment, in which the temperature of the 
denser and rarer water is measured by two thermo- 
meters placed at the bottom and top of a cylindrical 
In the history of pure science Rumford will be (639.) 
chiefly remembered by his espousing the (not new) His opi- 
theory that heat consists in a motion of some kind ac ane 
amongst the particles of matter, in opposition to the of heat im- 
opinions then so prevalent amongst chemists, which portant. 
almost tended to regard it as an element capable of 
forming combinations. Rumford’s view was mainly Derived 
based on the facts of friction, which he showed to be ff°™ expe- 
irreconcilable with the notion of a change in the spe- Pre edie 
jar, and nothing interferes with the natural tendency 
of a fluid to arrange its particles according to their 
specific gravity, the lighter resting on the heavier 
ones. It is to be regretted that Hope did not pro- 
secute original enquiry, for which the conception of 
this experiment, and the mode in which he conducted 
cific heat of the abraded matter, and-to be seemingly 
inexhaustible so long as the force producing friction 
is continued. His conclusion was, that the heat 
then generated cannot be a substance, but an affec- 
tion of body of the nature of vibratory motion. The 
amount of heat evolved in boring cannon is very 
1 Edinburgh Transactions, vol. v. 
® Rumford married (for the second time) Lavoisier’s widow ; his daughter (by his first marriage) became Madame Cuvier. 
Hence Cuvier’s Eloge of Rumford contains the most authentic particulars of his life. Madame Rumford survived until a few 
years since, residing at Paris, where she formed a link between the savans of the age of Lavoisier, and those of the middle 
of the nineteenth century. : 
