700 



SUMMAKY OF CURRENT RESEARCHES RELATING TO 



Fig. 137. 



in tlie stage, tlie bottom of each being closed by a piece of glass. 



They were protected by a cover-glass, wbicli was held in a pivoted 



frame, so that it could be turned away from the cell when desired. 



The instrument is of French workmanship. 



The arrangement for focusing is peculiar, the arm carrying the 



body being raised and lowered by 

 the milled head below the stage at 

 the back. 



Portable Microscopes. — The 



following forms complete, we be- 

 lieve, the history of portable Micro- 

 scopes, many of which have been 

 already illustrated in the Journal. 



Nachet's Pocket and Portable 

 Microscopes — The original form of 

 M. Nachet's Pocket Microscope for 

 powers up to 1/8 in., constructed 

 in 1854, is shown in fig. 137. The 

 metal box into which it is packed 

 measures 3^ x 2^ x If in. In use 

 the Microscope was screwed to the 

 box, as shown in the fig. The 

 mirror is seen through the opening in front, which is closed by a disk 

 of glass. It has a fine adjustment, and for oblique light it is sufS.- 

 cient to slide back the lid of the box as shown in the fig. 



Fig. 138. 



,-=^ 



To meet the demand for a portable Microscope of larger size, 

 M.Nachet devised the newer model shown in fig. 138. This when closed 



