No. 50193. 



Darkening Apparatus. 



31 



OS 



05 



O 



ft 



0> 







< 



O 



50 191. 1 : 36 



contacts alternately switch two pairs of electro-magnets in the circuit, the armatures (mounted on a . s. d. 

 common axis) of which translate their motion to a mercury circuit breaker. This latter acts as a 

 switch for the direction of rotation of the motor. The press button switch can be fixed in any desired 

 position of the lecture room or lecture table. The switch panel (carrying Nos. 50.197 and 50,199 

 combined) contains two lever switches for the darkening of 2 rows of windows and a press button 

 control for the skylight darkener. 



\Ve have had a number of such devices at work in our factory for many years, and these 

 have proved entirely satisfactory. We can also submit references to a large number of such apparatus 

 constructed for use outside our works. 



When inquiring for detailed estimates, we would respectfully ask that the necessary drawings of 

 the buildings and plans showing the situation may be forwarded. 



The price of the apparatus above described is composed of the prices of the following articles; 

 the cost for erecting is in each case quoted for separately. 



50.192. Blind, of black absolutely light-tight felt with special covering of fabric, together with 

 weighting bars, wood frame, shafts, wall bearings, cramp irons and rag bolts for fixing, 



according to size of window > . Price on 



application 



Or: 



50.193. Bunds, of black impregnated Sail Cloth, together with accessories named above; accor- Price on 

 ding to size of windows application 



Cl. 3L 



