80 JAMES CLERK MAXWELL. [CHAP. IV. 



with it, were by no means the only original inves- 

 tigations of this year. Mr. John Scott, of Scott 

 Brothers, Greenock, remembers being in the attic of 3 1 

 Heriot Eow, and seeing some preparations of jelly 

 with which James was experimenting there. Mr. 

 Scott left Edinburgh in the summer of 1846. What 

 was the exact object of these experiments and others 

 on gutta percha at this time is matter of conjecture. 

 There is little doubt that they prepared the way 

 for the investigation concerning the compression of 

 elastic solids. But it seems probable that they 

 were immediately suggested by Forbes's Theory of 

 Glaciers, which had recently called attention to the 

 whole question of the difference between solid, liquid, 

 and " viscous " bodies, and the different effects of 

 gravitation and pressure as applied to them. 1 Another 

 set of phenomena with which his mind was soon 

 afterwards engaged, viz. those of the refraction and 

 polarisation of light, were partly studied through 

 similar means. 



The work of his cousin, who was now a . rising 

 artist, still interested him. An entry in the father's 

 Diary, December 5, 1845, has reference to this : 



Walk with Jas. and Jemima to Botanical Garden to 

 inspect palm-trees for her sketching for a picture. 



Either in this or the following year I remember 

 his raising the question, Whether it was not possible 

 to determine mathematically the curve of the waves 



1 See especially Forbes's paper on the " Viscous Theory of Glacier- 

 Motion" in the Philosophical Transactions for 1846, pp. 143-210. 



