CH. II] 



DAYLIGHT GLASS 



and for the incandescent, nitrogen-filled tungsten (mazda) lamp. 

 It may be said in passing that these glass filters whiten any artificial 

 light, but that true daylight color values are given only under the 

 precise conditions for which the glass was worked out. It is also 

 gratifying to note that this successful solution of a long vexing 

 problem came only when the rigid training in physics and chemistry 

 and the facilities of a great manufacturing plant were brought 

 together. 



In the practical use of these daylight filters it was found by me that 

 the surface should be finely ground (frosted), or white frosted glass 

 should be used with it. Then the light should be enclosed in some 

 form of lantern to cut off all unfiltered light, and the daylight glass 



r 



I v 1 



FIG. 37. CHALET MICROSCOPE LAMP IN SECTION. 

 (About one sixth natural size.) 



dg dg Windows of daylight glass about 82 mm. square. One or both faces 

 are ground with very fine emery or carborundum to diffuse the light. 



me Mazda C lamp bulb of 100 watts. The filament of the lamp is opposite the 

 center of the daylight glass. 



S The lamp socket with snap switch at the left. 



v,v,v The ventilating flues. The one at the bottom goes all around; the ones at 

 the top are under the roof on the two sides, but not at the ends (fig. 38). The 

 light for the microscope extends directly through the daylight glass. That from 

 the windows and that escaping through the ventilating flues at the top is sufficient 

 to take notes by, to make drawings and to read. 



This has been named the Chalet Microscope Lamp, because the overhanging 

 roof for shading the eyes of the observer gives it the general appearance of a Swiss 

 Chalet (figs. 38, 58, 125). 



