THE PHOTO-MICROGEAPHiC CAMEEA llB 



that the type of apparatus in which everything is supported on, 

 and, if thought advisable, clamped down to, a solid and heavy 

 base, would be the better type ; in such case any vibration 

 affecting the apparatus would affect the whole of it equally, 

 and no disturbance of the components 

 in relation to each other would result. 



Where a simple type of apparatus 

 is for any reason decided on, and where 

 no special bench or supporting-table 

 can be entirely devoted to the work, 

 it is probable that what is known 

 as a * vertical ' camera would be the 

 best type to adopt. In this the micro- 

 scope is kept in a vertical position and 

 the light therefore has to be reflected 

 through the sub-stage condenser by 

 the mirror, as under ordinary con- 

 ditions in visual work. The camera 

 is supported over the microscope so 

 that the image is thrown on to the 

 focussing-screen, which therefore lies 

 in a horizontal position. This type of 

 apparatus necessarily has limitations ; 

 the length of camera is usually re- 

 stricted to from 18 to 24 inches, and 

 consequently, unless high-power pro- 

 jection oculars are used, high magnifi- 

 cations are not easily obtained. 



For the purpose, however, of 

 recording the results of researches 

 where critical definition is not of such 

 importance, this apparatus is ex- 

 tremely useful. One of the simplest 

 forms is that shown in Fig. 36, 

 made by Messrs. J. Swift & Son. It consists simply of an 

 aluminium cone which fits over the upper end of the body-tube 

 of the microscope. It is not more than about 12 inches in 

 length, and supports on its upper end a frame which carries 

 the ground-glass focussing-screen and the plate-holder. For 

 ordinary laboratory work it is a very useful piece of apparatus ; 



FIG. 37. Vertical Camera. 

 (Zeiss.) 



