NEW uses are constantly being found 

 for the blue glass electric light in- 



G96 Popular bcience MontliLy 



Euclid Never Thought of This Way New Uses Have Been Discovered for 

 of Studying Geometry Blue Glass Electric Lights 



I^HE study of geometry, especially of 

 the more advanced branches of spher- 

 ical and de- 

 scriptive geom- 

 etry makes 

 demands upon 

 the imagina- 

 tive power of 

 the students. 

 Perspective 

 drawings upon 

 the blackboard 

 are grasped on- 

 ly by the more 

 gifted students. 



Mr.J.O'Hara 

 Carson, who is 

 connected 

 with a manual 

 training school 

 in'.New Orleans, 

 found that the students 

 had no great difficulty in 

 learning the various 

 theorems, etc., so as to 

 pass their examinations, 

 but he noted that many 

 were unable to make a 

 practical application of 

 geometrical principles 

 accurately and con- 

 structively. A careful study of the subject 

 convinced Mr. Carson that many of the 

 students could not perfectly visualize 

 geometric figures drawn on a plane surface 

 and that it was this fact which made it 

 impossible for them to apply geometry 

 practically. So he invented several models. 



The illustrations accompanying 

 this article clearly demonstrate 

 the construction of these 

 models. The planes may 

 be made of wood, paste- 

 board or any other suit- 

 able material, the lines 

 of wire or strings. To 

 differentiate between 

 lines to be proved, con- 

 struction lines and im- 

 aginary lines, different color- 

 ing or different material may 

 be employed. These models 

 will also be useful in teaching 

 geometry to the blind. 



Our illustrations contrast the two 

 methods of teaching geometry 



can descents 

 which already 

 have a wide 

 range of uses. 

 A big laundry 

 in the South 

 has installed 

 blue bulb 

 lights for the 

 reason that 

 this light 

 makes the yel- 

 low stains in 

 cloth show up 

 plainly, and 

 therefore 

 enables the 

 workers to do 

 better laundry 

 work. In the West a 

 large mining company 

 uses blue glass lamps 

 over concentration tables 

 as this light assists in 

 bringing out the line 

 between the zinc and 

 iron ore. 



A Picture Frame and Easel for the 

 "Girl I Left Behind Me" 



THIS photograph frame is for the 

 soldier boys. The triangular flaps 

 are folded back, and the loop ribbon pro- 

 vided is slipped around the corner of one 

 of the flaps. The oval opening is large 

 enough to accommodate a pic- 

 ture 1^8 x23.^ in. The photo- 

 graph is slipped between 

 the frame and its back 

 through a slit at the top. 



The first illustration shows the simple principle of the 

 frame, the second its appearance with a photograph 



