THE FUTURE OF CHEMISTRY. 279 



two lines of research converge more and more day by day ; in the end 

 they will unite and become one. 



To sum up our reasonable expectations, we may hope that before 

 long the chemist, from the composition of any substance, will be able 

 to calculate all of its physical properties boiling-point, melting- 

 point, specific heat at every temperature, expansibility, density, index 

 of refraction, conductivity for heat and for electricity, and so on to 

 the end. I, for one, do not doubt that the day when this will be pos- 

 sible is approaching more rapidly than the majority of chemists sup- 

 pose. Until that time arrives chemistry cannot claim the honor of 

 being an exact science. In physics a result is to be accomplished 

 which will be complementary to this. Given the quantitative rela- 

 tions of the forces, we ought to be able, from the properties of any 

 body as regards one force, to compute its properties with regard to all 

 others. Knowing the thermal relations of any substance, for example, 

 we shall eventually be able to calculate at once its optical, electrical, 

 and magnetic properties. These results, to be achieved by physics, 

 can be brought about only in connection with the chemical investiga- 

 tions which this paper is intended to emphasize. 



But the future of chemistry does not end with the completion of 

 the researches which we have thus far considered. It is the glory of 

 science that every great achievement only opens the way for still 

 greater achievements lying far beyond. So, when chemistry shall 

 have reached the splendid future which I have ventured to suggest, it 

 will only find itself possessed of materials with which to start for a 

 grander future far away in the dim distance. We may expect that an 

 exact knowledge of the laws governing the physical properties of sub- 

 stances will enable us to foresee just what compounds are possible, 

 and by what reactions they may be obtained. Throughout the science, 

 accurate calculation will be substituted for much abortive experiment, 

 and both time and labor will be saved. The same lines of investiga- 

 tion, prolonged still further, will settle the much-vexed question of 

 the nature of the elements ; so that we may hope to know whether 

 they are all but varieties of one or two, or whether they are many and 

 essentially dissimilar. Upon the same experimental basis the truth or 

 falsity of the great atomic theory may rest. Given the knowledge 

 which we may expect to have concerning the physical relations of 

 substance, and we ought to be able to devise many crucial tests for 

 the idea of the atomic constitution of matter. All the great specu- 

 lative questions of modern chemistry must be eventually fought out 

 upon the battle-field of physics. 



Now, having recognized some facts concerning the intellectual 

 future of chemistry, let us inquire what material steps will best lead 

 up to them. What experimental work is most needed to begin with ? 

 Plainly, if we are to discover laws connecting the physical properties 

 of compounds with their composition, we must first determine the 



