PHYSICAL SCIENCE. 37 



Caucliy, Seebeck, Schonbein, &c. ; whose researches give 

 new access to those higher laws of force and motion which 

 we have marked as the ultimate aim of all philosophy. 



If seeking to denote briefly the moststriking characteristic 

 of modern science in its direction to Matter, we should name 

 at once the principle of Molecular action, as now applied 

 to physical research. Through this doctrine has been made 

 man's deepest inroad into the secrets of the natural world. 

 No single principle is so variously applicable : none has done 

 so much to promote discovery, or to authenticate and give 

 the form and force of law to the results obtained. And yet 

 it may be said to have had a lawless origin, and to have 

 been long the play of human phantasy under the garb of 

 science. We cannot here travel back to those early specu- 

 lations on atoms, which entered so largely into the staple of 

 the ancient philosophy ; and which the poetry of Lucretius has 

 better consecrated to later times than the most subtle prose 

 of the Greek philosophers. In every intermediate age, even 

 the darkest, the atomic doctrine in one form or other has 

 kept a certain hold on the minds of learned or speculative 

 men ; a natural effect of the facility with which it lends 

 itself to any hypothesis, however crude, regarding matter 

 and material phenomena. It was reserved for our own time 

 to render it at once the subject and instrument of legitimate 

 science ; the foundation of laws next to mathematical in 

 scope and exactness, and the most powerful of all aids to 

 ulterior research. 



This great achievement (for such it is) we owe mainly to 

 Chemistry ; and to John Dalton, the Quaker chemist, more 

 than to any one besides. Close approaches had been made 

 before to the doctrine of definite proportions, as repre- 

 sented by the molecules of matter in their combinations. 

 Such anticipations are recorded in the case of every great dis- 

 covery. But Dalton (speedily seconded indeed by other great 



