MICROSCOPE LAMPS 



163 



A disk of " day lite " glass inserted between bulb and condenser 

 adds greatly to the usefulness of the lamp, or one may employ 

 a Bausch & Lomb " auxiliary condenser " which has a " day- 

 lite " combination in the mounting. 



A tungsten filament microscope lamp closely approximating 

 an arc lamp in intensity and character has been recently described 

 by Gage. 1 It consists of an American locomotive headlight 

 lamp, having a very concentrated filament. It consists of a 

 gas-filled 6 volt, 108 watt, lamp with mogul base. The housing 



'is of the Gage " Chalet " type 

 shown in Fig. 97. A plano-con- 

 vex lens provides for either 

 // x ^ik parallel or converging light ac- 



FIG. 96. Tungsten Lamp with Con- 

 centrated Filament. 



FIG. 97. Bausch & Lomb Optical Co. 

 " Chalet " model microscope lamp with 

 " Daylite " glass. (Gage) X i 



cording as the lamp-bulb is moved forward or back in the 

 housing. 



Although, optically, the performance of tungsten incandes- 

 cent lamps is not equal to that of arc lamps, their greater con- 

 venience, steadier light and absence of adjustment annoyances 

 render them almost indispensable to the microscopist. 



In England a newly developed tungsten arc lamp known to 

 the trade as the " Pointolite " lamp has received much favorable 



S. H.: Modern Dark-field Microscopy. Trans. Amer. Micros, Soc. 

 39 (1920) in. 



