766 



Popular Science Monthly 



A Reflex Attachment for Use on 

 a Hand Camera 



AN extremely simple focusing device 

 l\ which actually transforms the or- 

 dinary view camera into a reflecting 

 camera, is made from card-board or or- 

 dinary box-boar i, and is 

 readily secured to the 



C a r d - 

 board box 

 used on 

 the back 

 of a regu- 

 lar cam- 

 era for re- 

 flex at- 

 tachment 



camera by a stout rubber band, no 

 other fastening being required. 



The simplest way to make this device is 

 to make a paper box (or to have it made 

 in a paper box factory) with the sides and 

 ends entirely closed in, and lined with 

 black paper. The height of the box 

 should be about 12 in., whether for a 4 by 

 5, or 5 by 7 camera. 



The width indicated in the sectional 

 view of the illustrations by X, should be 

 determined by measuring the distance 

 from the upper edge of the focusing door, 

 when it is swung back exactly 45 deg., to 

 the rear of the camera (the entire width 

 of the box in this direction should be the 

 distance X, plus about 1 in. more). The 

 lower front portion of the box is now cut 

 away, back to the measured distance X, 

 as shown. Next the sight opening at the 

 rear top edge of the box is.cut out, as seen 

 in the perspective view, and the box is 

 ready for use. The reflecting mirror, which 

 should be about the size of the focusing 

 door, may be attached to the box in any 

 suitable manner.— JuLius D. Garfield. 



This is due, in 



Notches in 

 cap to hold it 



Fastening a Breather Cap Securely 

 to Prevent Its Loss 



THE breather cap on an automobile 

 engine is very easily lost, especially 

 when the car has been in use for a con- 

 siderable length of time, 

 many cases, to the thread 

 on the inside of the cap 

 wearing out and losing its 

 holding power. 



To eliminate losses of 

 this nature, remove the 

 threads from the inside of 

 the cap, by turning them 

 out on a lathe. Then in- 

 sert two headless Ji-in. 

 machine screws in the upper end of tho 

 breather pipe. Provide two slots in the 

 cap of suflftcient size to clear the two set 

 screws. 



Merely drop the cap over the pipe and 

 then turn in a horizontal direction. The 

 two set screws entirely eliminate the pos- 

 sibility of the cap coming loose. — Adolph 

 Klein. 



Spreading the Air Currents from 

 a Desk Fan 



THE oscillating electric fan costs al- 

 most twice as much as the regular 

 fan and the air currents from it are not 

 steady and uniform, the breeze being 

 driven first in 

 one direction 

 for a short 

 time, immedi- 

 ately chang- 

 ing to another 

 direction. The 

 illustration 

 shows a new 

 device that 

 spreads the 

 air quite 

 evenly all the 

 time. This 

 device con- 

 sists of a num- 

 ber of metal 

 plates, clamped together at the angle 

 desired, and attached to the wire pro- 

 tector in front of the fan. The plates, 

 which are evenly spaced in a vertical 

 plane, divert the air currents steadily to 

 the parts of the room where ventilation 

 is most needed.— J. G. Pratt. 



Air spreading wings 

 fastened to the fan 



