Page:Popular Science Monthly Volume 89.djvu/474

 Photographic Self Help

��Pendulum for the Dark-Room

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��The pendulum swings

from one terminal to

the other in half a

second

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I'cight fas- tened to a thread measuring 9-} 4 'in length and hav- ing a loop at the end to be hung from a hook in the edge of a shelf, makes a capital aid in counting seconds for tim- ing the appear- ance of the image in the time sys- tem of develop- ment. One sec- ond counts at one end of the swing only, since the pendulum swings from one terminal to the other in half a second. The exact weight of the pendukim does not matter, the period of lime depending upon the length, not the mass. This device may be so constructed as to count minutes. A small metal hand may be placed at the anchoring end of the pendulum. As the weight shifts from one terminal to the other the hand will be actuated against some object which will enable the operator to count the periods.

An Improvised Reflecting-Camera

AX't^RY simple arrangement can be fitted to a hand-camera to enable the photographer to see the image on the ground glass, right side up, and without the use of a focusing cloth, while still holding the camera in the hand. This consists of an ordinary mirror, on thin glass, cut to the same size as the ground

���glass of the camera and mounted on the inside of the door covering the ground glass opening. The mirror is held at an angle of about 45° to the back of the camera by attaching a string or light chain to the door and the back of the camera. When it is desired to view the image on the ground glass the door is opened and allowed to drop down as far as the string will allow, and the eyes are placed at the top of the triangular open- ing thus provided. The image will be seen in the mirror, right side up.

Novel Device for Copying Pictures

THK illustration shows a handy appa- ratus for copying pictures. A piece of groove siding is ripped in the center, and two pieces 12 ins. long are dressed on the edges. A piece of glass about io".\i6'' is required. Two brackets are placed on the strips which hold the glass. Using an old drawing board the brackets and uprights are screwed in place, allowing space between the uprights for the glass. A strip of felt is placed on each narrow end of the glass, which is placed between the grooves. The copier sits directly facing the glass, after placing the j^icture on the table and securing it with thumb tacks. The reflection of the picture can be seen through the glass and copietl.

���A mirror the size of the ground glass of the camera is mounted on the inside of the door

��The picture is reflected throuRh the glass

and may be copied on blank paper with pen

or pencil

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