Popular Science Monthly 



149 



crease the current strength as demon- 

 strated by his many experiments in 

 this field. On exposing one of the 



y\ /OPAQUE BOX 



An impxilsion cell which has a solu- 

 tion of salt, sulphate copper and water 



plates to a strong light a current was 

 generated, proportional to the intensity 

 and varying with the distance of the 

 light. The peculiar fact was also noticed 

 that on running the exposed plate along 

 the spectrum, that is, exposing it to all 

 the colors of the rainbow, it was positive 

 at the red end but changed to negative 

 as it neared the violet. 



As yet, there has been no plausible 

 explanation as to the mysterious rela- 

 tions between heat, light and electricity, 

 yet the phenomena exhibited by these 

 peculiar cells may be more clearly 

 understood by the application of Dr. 

 See's new theory of light which states, 

 that: "The whole theory of ether is 

 abandoned as having no existence, light 

 being caused by electrically charged 

 particles, shaped like eggs, revolving 

 about their axes, and that electricity 

 itself cannot be separated from matter, 

 but always carries matter along with the 

 currents." 



There is a fascination about research 

 work in this comparatively new field of 

 photo-electricity which should entice 

 the experimenter who delights in solving 

 scientific problems; for the solution as to 

 the nature of electricity will probably be 

 found sooner or later by the simple appli- 

 cation and arrangement of the facts 

 gleaned from a patient scientific research 

 into fields, which as someone has said, 

 "makes thinner in places, the boundary 

 between the known and the unknown." 

 — ^A. R. MacPhersox. 



Inexpensive Stranded Aerial Wire 

 Made of Small Copper Wires 



COPPER wires may easily be twisted 

 together for antenna conductors by 

 using a hand brace or drill. One end of 

 the strand of wires is fastened to a post 

 or other support, the other end is secured 

 in the chuck of the brace or even merely 

 bound to it with a piece of strong wire. 

 When the strand is stretched out 

 straight and kept a little taut, one turn 

 of the brace for each foot of the total 

 length of the strand will produce an 

 evenly twisted cable. — E. F. Koke. 



An Electric Alarm Signal for 

 the Fisherman 



WATCHING a fish-line set in the ice, 

 on a bitter cold day is disagree- 

 able, so that the following plan will be 

 welcome. The usual "tip-ups" and 

 "jumping-jacks" ser\^e their purpose 

 nicely, but a more elaborate and interest- 

 ing device is an electrical signal. A 

 complete outfit may be carried in a box, 

 as easily as a tackle. An ordinary, 

 electric door-bell is mounted in a box, 

 and put in circuit with a three-cell 

 flashlight battery. Two strips of spring 

 brass are tacked to the outside of the 

 case. These are also connected, one 

 with a terminal of the battery and the 

 other with a binding-post on the bell. 

 The strips of brass are bent in such a 

 way that a slight pressure on one 



When a fish is hooked, the tug on the line 

 causes the contact which rings the bell 



immediately brings it into contact with 

 the other. The bo.x is opened, and set 

 near the hole where the fishing-line is 

 led into the ice. One end of the string 

 is tied to one of the brass strips, and as 

 soon as a fish is "hooked" he will tug at 

 the string and bring the strips together, 

 sounding the alarm until removed. 



