1886;] 



MICROSCOPICAL JOURNAL. 



the screen, suffices to adjust the focus 

 with the utmost exactness. 



In Dr. Sternberg's apparatus the 

 cord is run in a somewhat different 

 way. One end of the 

 cord is attached to a spool, 

 around which it is wound 

 several times, within easy ^1 

 reach of the operator. 

 The cord then runs over 

 the fine adjustment, and 

 a weight is attached to 

 the other end. The spool 

 revolves with sufficient 

 friction to prevent any 

 movement until it is turned 

 by the hand. 



The apparatus at the 

 National Museum^^was ar- 

 ranged by the writer in a 

 somewhat different man- 

 ner. There are two fo- 

 cussing cords running 

 under the camera, one 

 working the fine adjust- 



the focus can be accurately adjusted, 

 and the slight friction will maintain 

 it so. 



A very different form of apparatus 



is that 

 show n 

 in fig. 

 4 , in 

 wh i ch 

 the mi- 

 croscope is dis- 

 pensed with, 

 and the objec- 

 tive screwed 

 into the tube of 

 the camera it- 

 self. A focus- 

 sing-rod passes 

 under the cam- 

 era, as will be 

 seen in the fig- 

 ure. We have 

 not used this 

 apparatus, 

 which was de- 

 vised by Mr. 

 H.F.Atwood, 

 and are there- 

 fore not quali- 

 fied to say 

 much about it. 

 However, we 

 do not doubt 

 it has some 

 merit for ama- 

 teur work, one 

 of its good fea- 

 tures being the 

 absence of a 

 long micro- 

 scope tube, 

 which is fre- 

 '^S quently very 

 ^ff much in the 



Fig. 5.— Camera for Vertical Microscope. 



ment, the other the sub-stage of the 

 microscope. These cords act upon 

 the respective parts through the in- 

 tervention of pulleys devised by Mr. 

 Zentmayer. The cords have a 

 weight at each end, so balanced that 



mains to be illustrated, the method 

 of using the electric light with the 

 vertical microscope. This is shown 

 in fig. 5, which represents a Ger- 

 man outfit complete. 



Prof. Aubert mounts a small cam- 



