Address by Professor Rice. xxxix 



Transactions in 1788, but was not ])ul)lislied as a separate work 

 till seven years later. Not till 1815 was published William 

 Smith's Geological Map of England, the first example of system- 

 atic stratigraphic work extended over any large area of country. 

 To the beginning of our century belong also the classical and 

 epoch-making researches of Cuvier upon the fossil fauna of the 

 Paris basin. By far the larger part, therefore, of the develop- 

 ment of geologic science, with its far-reaching revelations of con- 

 tinental emergence and submergence, mountain growth and decaj' , 

 and evolution and extinction of successive faunas and floras, belongs 

 to the nineteenth century. Far on into our century extended 

 the conflict with theological conservatism, in which the elder 

 Silliman, James L. Kingsley, and others of the early members of 

 our Academy bore an honorable part, and which ended in the 

 recognition, b}' the general public as well as by the select circle of 

 scientific students, of an antiquity of the earth far transcending 

 the limits allowed b}^ venerable tradition. 



To our century also belongs chiefly the development in astron- 

 omy of the idea of the history of the solar system. It is, indeed, 

 true that, in the conception of the nebular hypothesis, Laplace, 

 whose " Theorie de la Monde " was published in 1796, was pre- 

 ceded by Kant and Swedenborg ; but the credit of a discovery 

 belongs not so much to the first conception of an idea as to its 

 development into a thoroughly scientific theory. Our century, 

 moreover, has added to those evidences of the nebular theory which 

 Laplace derived from the analogies of movement in the solar sys- 

 tem, the evidence furnished by the spectroscope, which finds in 

 the nebulae matter in some such condition as that from which the 

 solar system is supposed to have been evolved. 



But by far the most important contribution of this century to 

 the intellectual life of man is the share which it has had in devel- 

 oping the idea of the unity of nature. The greatest step prior to 

 this century in the development of that idea (and ])robably the 

 most important single discovery in the whole history of science) 

 was Newton's discovery of universal gravitation two hundred 

 years ago ; but the investigations of our century have revealed, 

 with a fullness not dreamed of before, a threefold unity in nature 

 — a unity of substance, a unity of force, and a unity of process. 



Spectrum analysis has tauglit us somewhat of the chemical con- 

 stitution, not only of the sun, but also of the distant stars and 



