370 KEVIEWS — MATHEMATICAL AND PHYSICAL SCIEHCE. 



steady light on the vexed question of the constitution of matter. The great num- 

 ber of scientific names of the first order of merit concerned in these numerous 

 discoveries marks the extraordinary fertility of the period 



Of the twenty-five years just elapsed, it is not so easy to speak with precision. 

 The voice of criticism may be fairly uttered with that reserve which every one 

 must feel in speaking of his immediate contemporaries. Yet it may perhaps be 

 stated without just cause either of offence or regret, that it has not on the whole 

 been characterised by the full maturity of so many commanding minds. Of the 

 great discoverers of the former period, several survived and continued their effi- 

 cient labors during no small portion 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 defining and connecting of facts and laws, and the deduction of the 

 theories started to explain them, as seemed to render fresh and striking originality 

 somewhat hopeless, whilst they occasioned a vast amount of useful employment to 

 minds of every order of talent. The undulatory theory of light, nobly blocked 

 out by the massive labors of Young and Fresnel, has afforded still unexhausted 

 material to the mathematician on the one hand, and to the experimentalist on the 

 other ; and ably have they fulfilled the double task, addiDg at the same time dis- 

 coveries whose importance and difficulty would have made them still more promi- 

 nent, 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 comparative 

 newness of the whole doctrine of these sciences, and the suddenness of their first 

 rise, and, perhaps, still more, the appearance of a philosopher of the very highest 

 merit, Mr. Faraday, who fortunately attached himself to this special department, 

 made the last thirty years an almost unbroken period of discovery. Radiant heat, 

 too, has been successfully advanced by labors 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 success, especially at the British and Russian national 

 observatories, which yields to that of no former period, Avhilst physical astronomy 

 has been cultivated by methods of still improved analysis, and has achieved one 

 triumph which Fiance need not grudge to England, nor England to France, — so 

 signal as to be placed by common consent in a position superior 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 except by the disturbance which it produced in the 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 national efforts in collecting reliable data from the remotest 

 corners of the globe is characteristic of the practical energy of the age. Pure 

 chemistry has been cultivated with extraordinary assiduity ; but though som<' 

 general principles have emerged, none are comparable, from their importance, to 

 the discovery of Dalton 



It seems to me impossible to exclude from a review, however slight, of contem- 

 porary 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 me- 



