106 CHEMICAL AND PHARMACEUTIC MANIPULATIONS. 
door c having a small semicircular opening at its base, is 
for the entrance of the gas pipe with an argand burner at- 
tached, as well also for the supply of air necessary to sus- 
tain combustion. The fire thus applied heats the sand on 
the top. The heated air has an exit through the circular 
aperture a, after having traversed the interior, which is di- 
vided lengthwise by the partition as represented by the dot- 
ted lines. The communication between the apartments is 
by an opening d in the diaphragm. In this way we ob- 
tain a graduation of the temperature of the bath. The 
Swedish chemists improve upon this construction, by an- 
nexing an apartment for drying filters and precipitates as 
well as for keeping liquids hot while filtering. 
"The blast or pneumatic table is an implement indispensi- 
ble to the chemist it being alike useful for bending glass tubes, 
blowing bulbs and other small apparatus, and for rapidly ef- 
fecting the decomposition and ignition of substances, which, 
for their fusion, would require an ordinary wind furnace. 
The most convenient form of this apparatus is shown by Fig. 
Fig. 5. 
5. The drawing is taken from one, in Professor Booth's la- 
boratory, made by J. Bishop, machinist of this city, ltconsists 
