140 



A Sprinkling Can as a Dark 

 Room Lamp 



N example of 

 how a com- 

 mon utensil can 

 be converted to a 

 purpose other 

 than the one for 

 which it was originally intended is 

 shown in the illustration. A night light 

 or a candle is placed inside a sprin- 

 kling can set on its side, and the semi- 

 oval opening which receives the water is 

 covered with a few folds of ruby tissue 

 paper affixed with music tape or glued 

 tags. In this simple way, a very service- 

 able dark room lamp is obtained. Venti- 

 lation is provided for through the noz- 

 zle ; the bend prevents the escape of light. 



w 



An Adjustable Arc Lamp 



OODEN 

 arms are 

 pivoted to the 

 wood support 

 by a screw and 

 washer. The 

 upper ends of 

 the arms are 

 drawn together 

 by a rubber 

 band passed 

 around them. 

 The carbons 

 are clamped in 

 spring clothes 

 pins, which, being fastened to the arms 

 with one screw only, allows them to be 

 swung up or down. By this means the 

 carbons may be adjusted at any angle to 

 each other. 



A spool is fastened at the lower part 

 of the wood support with a long screw 

 and washer. Two pieces of string are 

 tied to opposite ends of the spool, given 

 a few turns around it in the same di- 

 rection, and fastened to tacks at the 

 ends of the arms. The spool is fast- 

 ened with just enough tension so that 

 it will stay in place no matter which way 

 it may be turned in adjusting the dis- 

 tance between the carbons. 



Two pieces of spring brass wire are 

 made into coils somewhat smaller than 

 the carbons. These are sprung on the 

 ends of the carbons, making good con- 



Popular Science Monthly 



tact with them. The wires carrying the 

 current are connected directly with these 

 brass wires. Pieces of sheet fiber fitted 

 in the jaws of the clothes pin clamps af- 

 ford additional insulation, although the 

 wood parts, if dry, are quite sufficient 

 insulation for low voltages. 



With an no voU house-lighting cur- 

 rent, the lamp should be run in series 

 with suitable lamp bank or other resist- 

 ance. If the current is alternating, a 

 choke coil may be used in series with 

 it. 



Adjustable Printing-Frame Holder 



PHOTOG- 

 RAPHERS 

 are often re- 

 quired to print a 

 negative more 

 deeply at one end 

 than at another ; 

 but the ordinary 



method of holding the frame in the hand 

 is unsteady and unreliable. An adjust- 

 able support for a printing-frame, en- 

 abling the operator to set one end fur- 

 ther from the light than the other, is 

 shown in the sketch. It consists of a 

 wooden base upon which is supported 

 and pivoted a block fitted with two up- 

 rights. With the aid of a ratchet and 

 swivel indicated, the block may be moved 

 to various positions. The two uprights 

 are also furnished with a ratchet and 

 screw, which grasp the printing-frame 

 in the two trough-shaped groups pro- 

 vided in the latter. Various sized print- 

 ing-frames may be inserted in this 

 holder, and with the aid of the ratchets, 

 the distances from the light to different 

 portions of the negative may be easily 

 adjusted. 



Alcohol Burner 



AN excellent alco- 

 hol burner can be 

 made from an oil can 

 with the spout cut off 

 about an inch above 

 the body, and a wick 

 inserted. The flame 

 can be raised by pick- 

 ing with a pin or any 

 other sharp pointed 

 instrument. 



