Edward Livingston Youmans 79 



head, but this enforced method must have made it 

 still clearer. One of the most notable qualities 

 of his mind was the absolute luminousness with 

 which he saw things and the relations among 

 things. It was this quality that made him so suc- 

 cessful as an expounder of scientific truths. In 

 the course of his pondering over chemical facts 

 which he was obliged to take at second hand, it 

 occurred to him that most of the pupils in common 

 schools who studied chemistry were practically no 

 better off. It was easy enough for schools to buy 

 textbooks, but difficult for them to provide labo- 

 ratories and apparatus ; and it was much easier 

 withal to find teachers who could ask questions out 

 of a book than those who could use apparatus if 

 provided. It was customary, therefore, to learn 

 chemistry by rote ; or, in other words, pupils' heads 

 were crammed with unintelligible statements about 

 things with queer names, such as manganese or 

 tellurium, which they had never seen, and would 

 not know if they were to see them. It occurred to 

 Mr. Youmans that if visible processes could not 

 be brought before pupils, at any rate the funda- 

 mental conceptions of chemistry might be made 

 clear by means of diagrams. He began devising 

 diagrams in different colours, to illustrate the diver- 

 sity in the atomic weights of the principal elements, 



