8 Sketch of the Life of 



the Board of Excise of British gum which had been prepared 

 in their starch-manufactory, upon the pretence of its being 

 brown starch that had not paid duty ; the penalties sued for 

 amounted to upwards of 3000/. Samples were sent to him 

 for analysis, on a careful examination of which he found that 

 they possessed none of the properties of starch ; and when 

 the cause came on to be tried in the Court of Exchequer, in 

 which he was subpoenaed as an evidence for the defendants, 

 having obtained permission to repeat in court the experiments 

 by which he had ascertained the points in which British gum 

 differs from starch, the proofs were considered to be so deci- 

 sive, especially the one of the beautiful blue precipitate pro- 

 duced by the solution of iodine, that a verdict was imme- 

 diately pronounced for the defendants. 



It is truly wonderful that one man should be capable of 

 doing all that he did ; that, actively engaged in business as he 

 was for so many years, he should be able to write so much, 

 and yet be always prepared to follow with ardour any scien- 

 tific investigation, or chemical analysis, that might present 

 itself In experiments he was delicate and sure, never dis- 

 heartened by failure or by the tediousness of the operations, 

 and rarely stated any fact in his books till he had previously 

 verified it himself. 



The Chemical Catechism was the work to which its author 

 was the most fondly devoted ; it was his first production ; it 

 was the foundation on which his reputation as a chemist had 

 been raised : twenty years had not lessened the attachment of 

 the public to it, and the unusually large editions which he 

 published were called for with even more rapidity at last than 

 they had been at first. The Rudiments of Chemistry, and the 

 Chemical Essays, had both been received with unequivocal 

 marks of approval, — each had passed through large editions, 

 and been quickly sold ; the essays had been translated into 

 various languages, and both had been republished in different 

 parts of the United States : but the Catechism was, as it 

 were, identified with his very name, it bore all the character- 

 istics of his powerful and original mind ; to bring it nearer to 

 perfection had been his most assiduous labour, his most 

 cherished pleasure, for twenty years. The perusal of the Cate- 



