21 



Fig. 3. Drawing 

 to illustrate the use 

 of the ordinary 

 camera riding on a 

 vertical system. The 

 camera lucida frame 

 is pushed up out of 

 the way, its details 

 being, however, here 

 shown in a some- 

 wnat different manner 

 from that illustrated 

 in Fig. 4. 1, 1, 1, 1. 

 vertical girders im- 

 bedded in cement 

 under the building 

 and coming up 

 through the floor 

 without contact ; 2, 

 right hand box con- 

 taining a variety of 

 roller blinds work- 

 ing in a horizontal 

 direction and so 

 tinted as to give a 

 great variety of 

 transmitted light ; 3, 

 similar right hand 

 box of roller blinds; 

 4, 5, 6, roller blinds; 

 7, drawing board 

 horizontally and ver- 

 tically adjustable, 

 and also tipping to 

 pass platform 8 ; 8, 

 vertically adjustable 

 platform for the 

 support of object to 

 be drawn, in this 

 case supported on a 

 microscope stage; 9, 

 10, clamps for se- 

 curing 7 and 8 in 

 position; 11, 11, 

 screws for clamping 



all the previously described apparatus to the steel girders 

 1, 1,; 12, roller blind used as a diaphragm as described 

 description of Fig. 2; 13, diaphragm aperture in the roller blind 

 lower portion of the framework of the apparatus supporting 2-13; 15, 15. cross- 

 piece carrying the ordinary camera 17; 16, 16, screw clamps for securing the 

 camera after adjustment; 17, ordinary camera; 18, dark-well for securing 

 black or other background for objects; 19, one of the various adapters for vary- 

 ing the aperture in the top of the dark well; 20, inner roller blind being used to 

 secure a light background for the object being photographed; 21, one of the four 

 roller blinds blackened inside and forming, when piiUed up, the black inside surface 

 of the dark well; 22, 22, vertical slots in which the roller blinds 21, 24, &c., slide 

 in a light-tight manner; 23, anti-friction, bearings of the framework of the crnss- 

 piece 15; 24, one of the four blinds forming the sides of the dark well. 



— 1«»% 



1. 



12; 



1, 



the 

 14, 



