102 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Nos. 1 and 2 are suitable for mineralogica I and petrographical sections, 

 and No. 3 for microchemical reactions and interference figures in con- 

 vergent polarized light. Another pattern is made intended for biological 

 studies. 



o 



t-H 



For small magnifications, and therefore for considerable objective 

 distances, the objective does not require special protection. But for all 

 cases of high temperature the objective needs a small protecting cap 



