MICROSCOPE LAMPS 
163 
A disk of “ daylite ” 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.^ It consists of an American locomotive headlight 
lamp, having a very concentrated filament. It consists of a 
gas-filled 6 volt, io8 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 
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 5. 
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 
^ Gage, S. H.: Modern Dark-field Microscopy. Trans. Amer. Micros. Soc. 
39 (1920) III. 
