Galvanometers of High Sensibility. 



251 



delicate systems a simple matter. The length of the quartz 

 fiber is so chosen that the entire system can be drawn up into 

 the glass tube ; while in this position the tube can be placed 

 in the galvanometer without danger to the fiber or system. 



Fig-. 3 





§Il 



m| 



The coils being now pulled apart, the system can be lowered 

 into place, after which the coils can be approached as carefully 

 as is desired. The easy visibility of the system is another 

 important consideration; in particular we have found the 

 arrangement of telescope, mirror and milk-glass screen, as 

 shown in Hg. 2 and fig. 3, extremely convenient, as enabling 

 the operator at the scale to know the position of the system 

 independent of the spot of light. The telescope is adjusted so 



