296 
ELEMENTARY CHEMICAL MICROSCOPY 
is removed from time to time by means of capillary pipettes. 
This little apparatus also makes a convenient generator for hydro¬ 
gen and arsine in testing for arsenic. 
When temperatures of vaporization are needed the bulb con¬ 
taining the liquid can be introduced into the hot stage described 
Fig. 156. Tube for Microchemical Distillations. (Full Size.) 
on page 224, the receiving bulb being kept outside of the stage 
and cooled with wet filter paper, the tube connecting the two 
little bulbs having been bent at the proper angle. 
Ignition, Fusion, etc. — Operations involving heating to red¬ 
ness are best performed in small platinum cups or spoons, Fig. 
157, over the low flame of a Bunsen burner or that of a miniature 
blast lamp. 
Fig. 157. Platinum Cups for Fusions. (Full Size.) 
Fig. 158. Casserole for Microchemical Analysis. (Full Size.) 
In the absence of alkalies tiny cups with handles made of fused 
silica are convenient. Fig. 158; or tiny porcelain casseroles can 
be used. All the apparatus illustrated are standard commercial 
forms and may be obtained from dealers in chemical apparatus. 
Small crucibles are occasionally useful, especially those corre¬ 
sponding to No. 9 and 10 Meissan porcelain. Since, however, 
