274 MEMOIR OF DR. DALTON, AND 



measured by the narrow tube in all cases whatever, showing 

 that the solid matter had in reality entered the pores of the 

 water." 



This principle he applied to the analysis of sugar, showing 

 that its bulk in solution was equal to the amount of oxygen 

 and hydrogen combined as water, the carbon not occupying 

 any room. This rule Dal ton considered as absolutely and 

 universally true. He called it " the greatest discovery next 

 to the atomic theory." This idea in the hands of Messrs. 

 Playfair and Joule has had a fertile expansion, although 

 Dalton's mode of expressing the law has been limited to 

 certain classes of salts.* Had time and strength been given 

 him, he would no doubt, after this commencement, have 

 laboured well in the field of ''atomic volume." 



It is well when men become aware of the failure of their 

 powers, and are willing to give up their places to those whose 

 minds are in full vigor. The essay on the phosphates and 

 arseniates affords, on page 12, a melancholy instance of the 

 fate of those who overrate their strength. This sentence 

 occui-s in the form of an epitaph. — " I sent the account of the 

 phosphates and arseniates to the Royal Society, for their in- 

 sertion in the transactions. They were rejected. Caven- 

 dish, Davy, Wollaston, and Gilbert are no more." It sounds 

 like an epitaph on himself, and the volume tells still more 

 plainly that he had not followed the increased exactness re- 

 quired in science. Nevertheless, in one respect, the last 

 pamphlet is a model of himself, the rapid, hasty work, the 

 carelessness of the labours of others, and the new field struck 

 out in his remarks on sugar. In one point, however, it fails ; 

 in his early life he did not work otherwise than on the most 

 advanced ideas ; amongst the phosphates and arseniates he had 

 receded. 



The position which Dalton had attained seemed to demand 



• See "Memoirs of the Chemical Society." Vol. II., &c. 



