90 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
asbestos, is erected on four solid brass pillars. The sliding door T, 
with smoked glass window, is only opened to light up the gas flame and 
to centre the light point with a micrometer-screw. But the camera is 
then kept closed, because complete regulation is effected outside of and 
at the back of the camera. B is the projecting part of the burner ; M, a 
manometer for controlling the compressed oxygen ; B, the fine adjust- 
ment for the gases introduced through the tubes IS ; P, a levelling screw ; 
L, an aluminium arm leading into the camera, clamped by the screw Z, 
and intended to regulate the rear lens of the three-lensed condenser. 
In front of the camera, fastened by a strong aluminium bar, is the con- 
denser-carrier A, receiving both the front lenses of the condenser, which 
are therefore placed quite outside the camera, and get scarcely heated 
at all. They extend with their mounting to a circular opening in the 
front wall of the camera, and thus leave between themselves and this 
wall an air-space of 1 cm. clear, through which an extremely effective 
Fig. 11. 
air ventilation is brought into the inner camera. Immediately in front 
of the condenser stands the diapositive-holder D, in which, by means of 
the clip g the carrier for the glass diapositives can be slipped in and 
out. I) is shut off in front by a smaller aluminium plate, on which the 
leather bellows E is fastened, whose front aluminium frame slides on 
two metal runners of the objective-board O. On O, which can be moved 
backwards and forwards by means of a milled screw-head H, is a lateral 
micrometer screw c, which serves for centering the flame image. 
The diapositive-carrier D is movable on two prismatic bars F in two 
directions by clamp-screws s , which bars move in the strong aluminium 
rail of the condenser-plate A. By relaxing s, the diapositive-carrier, the 
bellows, and objective-board can be removed ; the front condenser lens 
is then completely free, and the apparatus can now be used for the pro- 
jection of microscopic preparations (fig. 11). But if such objects as 
culture-tubes and plates, chemical reactions, &c., require to be projected, 
the objective-board and objective (without the bellows) are re-inserted, 
and these objects find ample room between A and 0. 
