"ube Diaphragm 

 with Society Screw 



the 



..'JFronUens \0bjecl i ve 

 ..WorKingD'fttanc*/ 



Slide' 



Object 



FIG. 1. AUL OF THE PARTS MENTIONED IN 

 THE TEXT ARE INDICATED ON THIS FIG- 

 URE AND THE FRONTISPIECE. 



PART I 



CARE OF 



THE 

 MICROSCOPE 



THE STAND 



Every microscope 

 regularly leaves the 

 factory in a case 

 made especially for 

 it in which it fits 

 securely. If it is to 

 be carried any dis- 

 tance it should be 

 carried in the case. 

 It should be left in 

 the case when not 

 in use unless some 

 other means are pro- 

 vided to protect it 

 from dust. 



Dust settling upon 

 the highly polished 

 surfaces is apt to 

 scratch them when 

 it is removed. It 

 works into the bear- 

 ings of the instru- 

 ment, making them 

 work hard and un- 

 necessarily wearing 

 them. 



