THE PROGRESS OF SCIENCE FROM 1836 TO 1886. 513 



of individual facts and observations, colligated by minor laws and 

 analogies, but unilluminated as yet by the broad light of any great 

 and all-embracing general principles. Since Dalton's atomic theory, 

 indeed, no philosophic generalization of the very first magnitude has 

 been introduced into chemistry. But generalizations of the second 

 order vastly interesting to chemists, and to chemists alone have 

 been made in such numbers as to defy enumeration ; wider concep- 

 tions have in many ways sprung up ; the science has assumed a new 

 form ; and some of the results of spectrum analysis and of the new 

 chemistry lead to the hope that this science too is on the eve of arriv- 

 ing at that stage of far-reaching fundamental truths, which it is the 

 special function of our generation to bring about. 



Mathematics has also undergone a new development, scarcely 

 capable of being rendered comprehensible to the lay intelligence. 



The applications of physical, electrical, and chemical science in the 

 great mechanical and industrial inventions of our iron age, belong 

 elsewhere, and are already familiar in many respects to all of us. 

 Railways slightly antedate the epoch ; the telegraph is just coeval 

 with it. The first submarine cable was in 1851, the first transatlantic 

 in 1866. Electro-plating, the steam-hammer, the Armstrong gun, the 

 Bessemer process, must not be forgotten. Other triumphs of applied 

 science fall more fitly under another heading. 



Among the concrete sciences, astronomy has made vast advances 

 during the past half-century. Lord Rosse's great telescope was set 

 up at Parsonstown in 1844. Two years later, Leverrier and Adams 

 made their curious simultaneous discovery of the planet Neptune. 

 But it is not so much in new lists of suns or satellites though the 

 name of these alone has, indeed, been legion as in the fresh light 

 cast upon the nature and constitution of older ones, that our age has 

 been most singularly successful. The invention of the spectroscope, 

 and the rapid development of spectrum analysis, have placed in the 

 hands of astronomers a method and an instrument inferior in value 

 only to the telescope itself. It is not so long since Comte dogmati- 

 cally declared we could never know anything of the chemical compo- 

 sition of the fixed stars. Scarcely were the words well out of his 

 mouth when the invention of the spectroscope and its application to 

 the spectra of incandescent bodies brought the investigation of the 

 elements in the sun and stars well within the reach of human possi- 

 bility. The successive researches of Wheatstone, Foucault, Secchi, 

 Bunsen, Kirchhoff, and Norman Lockyer, exactly covering our fifty 

 years, have at last enabled us to prove almost with certainty the 

 presence in the solar envelopes of several metals already known in . 

 the earth's crust, such as potassium, sodium, calcium, iron, nickel, and 

 chromium. So delicate is the spectroscopic test, that it renders pos- 

 sible the detection of so small a fraction as aoo . ooo .wy P art ^ a 

 grain of sodium. And by revealing bright lines in the spectrum not 



TOL. XXXI. 33 



