CH. VIII] 



-M1CROGRAPHY 



205 



Fig. 161. Vertical Camera for photographing objects in a horizontal posi- 

 tion. The camera is attached to a double frame connected by bent metal pieces 

 fastened to the lower frame and sliding in a groove in the upper. The two 

 frames can then slide over each other without separating. For moving the 

 outer frame a rack work is put on the lower or inner frame and a pinion with 

 a toothed wheel on the outer one. This is turned by the wheel shown. To 

 prevent the camera running down in the vertical position a pawl is held in place 

 by a spring. This may be released by a smaller wheel than that serving to 

 move the pinion. This rack and pinion are fine enough for focusing with the 

 photogaphic objectives employed. 



The camera bed is graduated in centimeters so that the exact extent of the 

 bellows can be determined by inspection. 



The support on ivhich the specimen rests is of heavy glass on vertical rods 

 about w centimeters long. The background is placed on the table top about 10 

 cm. below. This arrangement of support and background serves to avoid the 

 dense shadows which make it difficult to determine exactly the limits of the 

 specimen. To make the apparatus steady the right hand end of the camera table 

 is heavily weighted. The tables have leveling screws in the legs. 



