678 



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. 



