FIRST DISCOVERIES. 11 



their angles and forms, when his nomination to the 

 professorship of physics in the Lycee of Tournon 

 surprised and distressed him. M. Balard repaired 

 immediately to the bureau of the Minister of Educa- 

 tion, and spoke of his assistant in terms which caused 

 the nomination to be cancelled. Pasteur remained in 

 the laboratory of the Ecole Normale. 



With a view to mastering the science of crystal- 

 lography, he took for his guide the extensive work 

 of M. de la Provostaye, resolving to repeat all the 

 measurements of angles and all the other determina- 

 tions of this author with a view to a comparison of 

 their respective results. The work of M. de la Pro- 

 vostaye, who was distinguished by the exactitude of 

 his researches, had for its subject the tartaric and 

 paratartaric acids and their saline compounds. 



Two or three years ago, while we were walking to- 

 gether along a road in the Jura, M. Pasteur, after 

 quoting textually the note of Mitscherlich, described 

 to me with enthusiasm the pleasure he had experienced 

 in crystallising tartaric acid and its salts, the crystals 

 of which, he said, rivalled in size and beauty the most 

 exquisite of crystalline forms. 



' I should have great difficulty,' I remarked, ' in 

 following you through the labyrinth of tartaric acid, 

 tartrates, and paratartrates. However much your 

 other studies have attracted me, those which had for 



