| ia 
Optics. 
Cuar. I, § 1.] 
tion of the latter; and a few happily still remain to 
claim the respect and veneration of their disciples 
and successors, But the vast steps so recently made 
in Optics, in Electricity, in Magnetism, in Thermotics, 
and in Chemical principles, tended of necessity to call 
forth such an amount of laborious detail in the de- 
fining and connecting of facts and laws, and the de- 
ductions of the theories started to explain them, as 
seemed to render fresh and striking originality some- 
what hopeless, whilst they occasioned a vast amount 
of useful employment to minds of every order of ta- 
lent. The undulatory Theory of Light, nobly blocked 
out by the massive labours of Young and Fresnel, 
has afforded still. unexhausted material to the ma- 
thematician on the one hand, and to the experimen- 
talist on the other; and ably have they fulfilled the 
double task, adding at the same time discoveries 
whose importance and difficulty would have made 
them still more prominent, had they not been the 
legitimate consequences of a still greater discovery 
already in our possession. Nearly the same might 
have been said for the sciences of Electricity, Electro- 
magnetism, and Electro-chemistry, had not the com- 
Electricity. parative newness of the whole doctrine of these sci- 
Heat. 
Astrono- 
. practical energy of the age. 
ences, and the suddenness of their first rise, and, per- 
haps still more, the appearance of a philosopher of the 
very highest merit, Mr Faraday, who fortunately at- 
tached himself to this special department, made the 
last thirty years an almost unbroken period of dis- 
covery. Radiant Heat, too, has been successfully 
advanced by labours comparable perhaps to those 
which marked its first rise as a science, and some 
other topics connected with heat have risen into 
great and practical consequence. Astronomy has 
been prosecuted with a systematic assiduity and suc- 
cess, especially at the British and Russian national 
observatories, which yields to that of no former pe- 
riod, whilst physical astronomy has been cultivated 
by methods of still improved analysis, and has 
achieved one triumph which France need not grudge 
to England, nor England to France,—so signal as 
to be placed by common consent in a position su- 
perior to any since the first publication of the theory 
of gravitation, more than a century and a half be- 
fore. This was the prediction of the position in 
space of a planet whose existence was unknown ex- 
cept by the disturbance which it produced in the 
Magnetism. movements of another. Terrestrial Magnetism has, 
for the first time, aspired to the rank of an exact 
science. In an illustrious philosopher of Germany, 
it has found its Kepler ; and the combination of na- 
tional efforts in collecting reliable data from the re- 
motest corners of the globe is characteristic of the 
Pure Chemistry has 
been cultivated with extraordinary assiduity; but 
though some general principles have emerged, none 
are comparable, from their importance, to the dis- 
covery of Dalton. To cite, then, at present, but a 
few names, amongst the most conspicuous benefac- 
VOL. I. 
PLAN OF THIS DISSERTATION. 
801 
tors of science of the last, or contemporary period, are 
MM. Airy, Cauchy, Hamilton, and MacCullagh ; 
MM. Faraday, Melloni, and Gauss; Sir John Her- 
schel, M. Struve, and Lord Rosse; MM. Plana, 
Poisson, Leverrier, and Adams ; MM. Mitscherlich, 
Liebig, and Dumas. 
It seems to me impossible to exclude from a re- 
view, however slight, of contemporary progress in) 
the exact sciences, the advances which have accrued * 
to them both directly, and, as it were, reflexively, by 
the astonishing progress of the Mechanical Arts. The 
causes, indeed, which called them forth are some- 
what different ‘from those which are active in more 
abstract, though scarcely more difficult, studies, 
Increasing national wealth, numbers, and enterprise, 
are stimulants unlike the laurels, or even the golden 
medals of academies, and the quiet applause of a few 
studious men. But the result is not less real, and 
the advance of knowledge scarcely more indirect, 
The masterpieces of civil engineering—the Steam 
Engine, the Locomotive Engine, and the Tubular 
Bridge—are only experiments on the powers of nature 
on a gigantic scale, and are not to be compassed 
without inductive skill as remarkable and as truly 
philosophic as any effort which the man of science 
exerts, save only the origination of great theories, of 
which one or two in a hundred years may be con- 
sidered as a liberal allowance. Whilst then we 
claim for Watt a place amongst the eminent contri- 
butors to the progress of science in the eighteenth 
century, we must reserve a similar one for the Ste- 
phensons and the Brunels of the present: and 
whilst we are proud of the changes wrought by the 
increase of knowledge during the last twenty-five 
years on the face of society, we must recollect that 
these very changes, and the inventions which have 
occasioned them, have stamped perhaps the most 
characteristic feature—its intense practicalness—on 
the science itself of the same period. 
Having thus briefly reviewed the course of disco- 
very since the latter portion of the eighteenth century, 
I proceed in the succeeding chapters to attempt to 
(11.) 
Mechanical 
(12.) 
Review of 
the History 
of Science 
sketch it more in detail, dividing the sciences into in this 
groups, and in each of these endeavouring to present Essy- 
a lively view of its progress by connecting it with 
the individnal career of the eminent men who have 
most contributed thereto, and introducing collaterally 
the chief results obtained by their contemporaries. 
In this manner I hope, on the one hand, to escape the 
formality of a history of science, and the meagre de- 
tail which our limits would prescribe to so vast a sub- 
ject ; and on the other to be enabled to impress upon 
the reader (as seems to be the design of these Essays) 
the leading facts and features of discovery in every 
age, together with the intellectual characteristics of 
the greatest minds which contributed to it. 
It is with no overweening confidence that I lay the 
51 
13.) 
