Page:Popular Science Monthly Volume 91.djvu/694

This page needs to be proofread.


��Popular Science Monthly

���Rivers That Flow in Two Different Directions

HILE making meas- urements of river flow in the upper Mississippi River ba- sins and in the Hud- son Bay recently, the United States Geo- logical Survey dis- covered that some of the rivers under investigation empty into the Arctic Ocean during certain seasons and into the Atlantic Ocean at other times.

��To take the picture the camera is held tight against the finger print and a lever is pressed

A Special Finger-Print Camera for the Modern Sherlock Holmes

FOR police officers and others who have need of getting finger-print evidence from material that cannot be preserved or removed from its environment, a special camera has been perfected. It takes a photograph of the finger print wherever it may be. In operating the camera no photographic skill or experience, nor even a tripod is necessary. The camera is held tight against the surface of the door, ceiling, wall paper, or wherever the finger print has been made. The shutter release lever is then pressed down ;

this automatically .* .,

closes the circuit to .....*»--*"' •-.-.■ '""—h. **">* the four lamps inside £ . ""-'••-.! "S.c"^

the camera and thus ; ., *^frht

lights them, provid- ing the illumination for the exposure. The necessary cur- rent is provided by storage batteries in- side the camera.

��Details of the combination ink-bottle holder, ink-feeder and stopper, for the artist's use

��Efficiency as Applied to an Ink-Bottle Holder

THE accommodating bottle holder shown in the accompanying illus- tration is designed principally for the convenience of the pen-and-ink artist. The device does a great deal more than simply to provide a stand for the inkwell. It has a top section as well as a base, and this top section contains two disks to cover the bottles used, thus doing away with cork bottle- stoppers. Each of these disks is pro- vided with a quill which dips down into the bottle when pressure is exerted on the finger-piece of an attached arm which is led from the outer surface of each disk to the base of the stand. Additional pressure causes the quill to rise out of the bottle, bringing with it a drop of ink which it feeds to the point of the pen held to receive it. In this way the evaporation of the ink is prevented.

Different colors of ink may be kept in the separate bottles. A small basin is provided at one side of the wells to hold a supply of water, and cleaning cloths for the pen points. Complicated as the con- trivance seems to be, it requires only a slight pressure of the finger .": ; . on one of the arms to raise the <\ y top and elevate the drop of />~y\ ink for the pen. The

-:?;•>. « economy of time and of

ink is apparent, since there is no clogging of the ink from dust, no evaporation, and no cork stopper to be removed each time the bottle is used.

��� �