CHAP, xvi Wedgwood's Journey into Cornwall 181 



companion iii any future journey into the same 

 places." 



The Memorandum Book and Commonplace Book, 

 from which we select the following extracts, seem not to 

 have been examined by any of Wedgwood's biographers. 

 At least no notices of them have been published. Yet 

 they are very curious documents, throwing considerable 

 light upon the character of the great potter. Careful 

 and cautious observation was his principal characteristic. 

 The Commonplace Book gives, in his handwriting, a 

 long account of the horse's foot ; he describes its sole, 

 its treatment, its proper shoeing, and so on. 



He gives Mr. Smeaton's views on the expansion of 

 metals; and Dr. Priestley's account of the different 

 kinds of air. He records experiments on different kinds 

 of cobalt ; with observations on glazes, clays, zaffre, and 

 nickel ; and the method of producing various colours 

 after firing. 



In his Memorandum Book, Wedgwood devotes whole 

 pages to experiments on Thermometers. His object 

 was to ascertain the principle of certain clays diminish- 

 ing in bulk by fire; his trials were very elaborate. 

 He tried various mixtures of clays, from red heat up to 

 the strongest that vessels made of clay can support. 

 He records that " some of the present Cornish porce- 

 lain clays seem to be the best adapted, both for sup- 

 porting the intensity and measuring the degrees of 

 heat." Eventually, Wedgwood published the results of 

 his experiments ; and he was elected a Fellow of the 



