5 FOUNDATIONS OF THE HYPOTHESIS 11 



works. The writings of the others have now only a historic 

 interest, 1 as they exhibit, in the rise and fall of a philo- 

 sophical system, a picture of the intellectual life of man 

 which becomes the more distinct by a narrow limitation to 

 a special study. 2 The kinetic theory of our day has come 

 to life quite independently of those forgotten predecessors. 

 We may look on Daniel Bernoulli as the first author of 

 the fundamental notion of the kinetic theory so at least I 

 think I have proved in the following pages ; but he who 

 has the honour of being acknowledged as the author of a 

 scientific system a mathematical theory founded on this 

 notion is Clausius, and with him Maxwell has done the 

 most to promote and develop the theory. 



1 Gehler's Physik. Warterbuch, iv. 1828, p. 1049; Clausius, Pogg. Ann. 

 cxv. 1862,'p. 2, Abhandl. pt. ii. p. 230 ; transl. Phil. Mag. [4] xxiii. 1862, pp. 417, 

 512 ; Lothar Meyer, Theoriender Chemie, 2nd ed. p. 29, 5th ed. p. 30. 



2 A thorough exposition of the ' Fall of the kinetic theory of atoms in the 

 seventeenth century 'is given by Dr. Kurd L ass wit z in Pogg. Ann. cliii. 

 1874, p. 373, as well as in his Geschichte der Atomistik, 2 vols., Hamburg and 

 Leipsig 1890. The influence of the corpuscular philosophy is there portrayed, 

 and the harm done by Newton's doctrine of the kinetic theory of atoms. I 

 might add that it fell into complete oblivion in the eighteenth century, when 

 the Cartesian philosophy, with which it was in constant strife, was supplanted 

 and Kant's arose; and it remained forgotten by all, with few exceptions, of 

 the natural philosophers of the present century, who take but little account of 

 older works. 



