326 



PROJECTION APPARATUS FOR DRAWING [Cn. X 



FIG. 183. 



ARRANGEMENT FOR DRAWING OBJECTS THE SIZE OF LANTERN- 

 SLIDES. 



The illumination can l:c by the ordinary heavy lantern-slide current, or by 

 the small current of the house lighting supply. The 5 ampere current is 

 sufficient for drawing. If one wishes to draw on a horizontal surface, then a 

 mirror is put beyond the objective. If the drawing is on a vertical surface, as 

 for wall diagrams, then the mirror is removed. 



w Supply wire cable from the outlet box (fig. 3). 



/ u. 1 Wires to the arc lamp. 



s Table switch. 



r Rheostat of the theater-dimmer type with a range of 5 to 35 amperes. 



/ Arc lamp. 



a a a Axis. 



c Condenser and water cell. 



Is Lantern-slide support. 



o Projection objective for large objects. 



m 45 mirror to reflect the light down upon the horizontal drawing shelf. 



as Adjustable drawing shelf. 



b Baseboard with track along which the, carrying blocks can be moved 

 independently. 



attached shelf, a small drawing-board may be clamped to the shelf 

 as shown in fig. 183. 



