344 LEADING AMERICAN MEN OF SCIENCE 



say exactly what will result from any given combination of forces. 

 The law of gravitation converted the chaos of forty centuries of 

 astronomical observations into a cosmos, but chemistry is still 

 without a Newton. The astronomer can calculate with great 

 accuracy the forces acting between two planets in conjunction 

 and what would be their movements in consequence; the physi- 

 cist can do the same for two magnets, but the chemist has no meas- 

 ure of the forces acting between two elements, in fact, he cannot 

 even tell in many cases whether there will be any reaction when he 

 puts them together under new conditions. 



The astonishing progress of physics during the last half century, 

 resulting in the transformation of modern life through new methods 

 for the utilization of heat, light and electricity, is chiefly due to 

 the use of the greatest of all scientific generalizations, the law of 

 the conversion of energy. But although this forms the basis 

 of chemistry as much as of physics, chemists have had to get 

 along without its aid because there was no known way of applying 

 it to chemical phenomena in general. The physicist starting from 

 a few well-established fundamental principles makes use, in draw- 

 ing deductions from them, of the most powerful intellectual tool in 

 the hands of man, but the chemist is confined to the slower process 

 of inductive reasoning from multitudinous observations, of which 

 very few are capable of expression in quantitative form so as to be 

 utilizable mathematically. Physics and chemistry have not been 

 on speaking terms, for they talked different languages. It was 

 largely due to Willard Gibbs and others working along the line he 

 indicated that they are being brought together, and the wedded 

 sciences have already proved fruitful. The new science, physical 

 chemistry, in which the methods of physics are applied to the prob- 

 lems of chemistry, has within the few years of its existence made 

 very rapid progress and has already solved many old puzzles and 

 brought to light many new truths. We are not yet in sight of 

 any fundamental principles which shall bring together all the 

 complicated phenomena of chemistry, but we owe to Willard 

 Gibbs the first step toward accomplishing this by drawing from 

 the laws of thermodynamics rules explaining a great variety of 



