1885.] 



MICROSCOPICAL JOURNAL. 



149 



of fi^htinjif it from the moment the 

 raw material came into my hands ; 

 then, and not till then, did I receive 

 my reward. To give an idea of 

 how poor the material is in its orig^i- 

 nal condition, I will state that the 

 amount contained in a homeopathic 

 vial a quarter of an inch deep can- 

 not be procured from less than one 

 quart of the raw material. 



o 



Fiisoldt's Detachins: Nose-Piece. 

 The device of Mr. Charles Fasoldt 

 for rapidly changing 

 objectives, which 

 is illustrated in Fig. 

 22, has already be- 

 come very popular. 

 It is an ingenious de- 

 vice, and it is said to 

 be quite accurate in 

 centring the lens. 

 The method of operat- 

 ing it is easily under- 

 stood from the figure. 

 As will be seen, the 

 device screws into the 

 nose-piece of the mi- 

 croscope, and is ad- 

 justed in ally desired 

 position by means of 

 a collar provided for 

 the purpose. The 

 objective is held se- 

 curely by a spring 

 working against the 

 lever. The society- 

 screw in the nose- 

 piece is in three seg- 

 ments — one on the 

 movable piece con- 

 nected with the lever, 

 the other two on the 

 opposite side of the =: 

 nose-piece. The ob- 

 jective should be 

 marked so that it can 

 always be put in 

 with the screw- 

 thread in the right 

 position. The maker 

 gives the following instructions for 

 using the device : — ' Take the ob- 



jective in the right hand, between 

 the first and second fingers, as 

 represented in the cut, place it in the 

 nose-piece, then let go the lever with 

 left-hand finger, and turn the objec- 

 tive to its resting place. ' The objec- 

 tive should be turned back one-eighth 

 of a turn, and a black mark made on 

 it, which should stand between the 

 fingers as a guide, when the objec- 

 tive is put into nose-piece. Then it 

 will invariably require only one- 

 eighth of a turn to bring it home.' 



If the ob- 

 jective is 

 put in just 

 right it will 

 not require 

 to be turned. 

 This nose- 

 piece has 

 been very 



Via. 22. — Fasoklt's Deuiching Nose-piece. 



j highly spoken of by those who have 

 I used it. We have given it a trial and 



