HAND AM' OTHER APPARATi 



A piece of round india-rubber placed between two 

 quarter plates, is made to occupy the same posi- 

 tion as the dotted lines in figure (20). A board 

 slightly narrower than the plates and india-rubber, 

 has a piece cut out of it 4J inches wide and about 

 the same length ; four thin strips are fastened along 

 its edges and the plates with the india-rubber forced 

 down between them ; when this has been done the 

 cell is filled with the solution, and the india-rubber 

 pressed down so as to complete the ring and prevent 

 evaporation. 



This cell may with advantage be used on all occa- 

 sions instead of, the blue glass. 



A bull's eye condenser of about four inches focus and 

 one and a half inches diameter, is indispensable. 

 It should be mounted as shown in the engraving 

 the base being made of lead to increase its stabi- 

 lity. 



Having finished our description of the apparatus 

 required in Micro-photography, we wish finally to 

 impress on the reader the necessity of making them 

 as well and accurately as possible, and not to attempt 

 their manufacture himself unless he is a good mechanic. 



We now pass to the arrangement of the dark 

 room. The outlay is very small and will amply re- 

 pay the photographer. 



Any spare room may be selected for its erection, 

 preferably on the ground floor, near or if possible in 

 the apartment set apart for micro-photography and 

 the instruments used for that purpose. 



