Page:Popular Science Monthly Volume 92.djvu/782

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��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

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