CHAP. L, 1.] 



PLAN OF THIS DISSERTATION. 



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- 

 Optics. 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 corn- 

 Electricity, parative newness of the whole doctrine of these sci- 

 Ileat. 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 tho 

 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 

 Astrono- 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 

 Chemistry, practical energy of the age. 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- 



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 j n Mechanical 

 the exact sciences, the advantages which have accrued 

 to them both directly, and, a* 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- (12.) 

 very since the latter portion of the eighteenth century, ^ ev ^- w t f 

 I proceed in the succeeding chapters to attempt to O f Science 

 sketch it more in detail, dividing the sciences into in this 

 groups, and in each of these endeavouring to present ^ S8a y- 

 a lively view of its progress by connecting it with , 



the individual 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 (13.) 



