78 EARLY LIFE. 



flattery of his letters. Fourcroy gives Black the full 

 credit of his discoveries, and distinctly states that 

 they had been the foundation of the new system 

 (Elem. de Chym., i. 30, 40; Syst. de Cour. Chy- 

 mique, ii. 28, 40). 



I remember the first time I ever was in his society. 

 When I went to take a ticket for his class, there stood 

 upon his table a small brass instrument for weighing 

 the guineas given. On learning who I was, he entered 

 into conversation in a most kind manner. He said 

 he concluded I was not a medical student, as all but 

 two or three of the class were ; among whom were 

 Messrs Yogt and Watenbach of Hamburg, and M. 

 Koenig of Dresden. He asked what classes I had 

 attended, and expressed himself much pleased with 

 what I told him of the great interest I took in math- 

 ematics and natural philosophy, recommending the 

 study of Newton's Optics, both for the substance and 

 the method. When I was going away he said : " You 

 must have been surprised at my using this instru- 

 ment to weigh your guineas, but it was before I knew 

 who you were. I am obliged to weigh them when 

 strange students come, there being a very large 

 number who bring light guineas; so that I should 

 be defrauded of many pounds every year if I did not 

 act in self-defence against that class of students;" 

 and he particularly mentioned one class, describing 

 them. 



The qualities which distinguished him as an 

 inquirer and as a teacher followed him into all 



