CHEMICAL AND PHARMACEUTIC MANIPULATIONS. 105 
may be diminished. The highest amount of heat produced 
by this apparatus is a cherry-red by daylight. For burning 
off filters in a platinum crucible, a cylinder of 2\ inches 
diameter is amply sufficient; but for heating larger vessels, 
such as capsules, those of 4 — 5 inches diameter are desira- 
ble. This mode of burning the gas presents the advantages 
of producing any degree of heat as high as a red, of not 
blackening vessels immersed in the flame, and of avoiding, 
with more certainty, the fracture of porcelain or glass ves- 
sels, from the diffusive character of the flame." 
"The ring n, sliding upon the rod of the upright stand 
serves as a support for a retort, capsule or crucible. A 
second chimney g placed over the crucible creates a uniform 
and constant draught. 
" The whole of this apparatus is movable, and when the 
space which it occupies upon the table is required for other 
purposes, it is only necessary to disconnect it from the 
hanger, and place the whole aside, to be as readily replaced 
again when wanted. 
"The introduction of gas into the room also allows the 
substitution of an economical table sand-bath (Fig. 4,) for 
the more cumbersome one described at pp. 30, 31. It con- 
Fig. 4. 
\1 u 
sists of a copper box B eighteen inches long, twelve inches 
wide and six inches deep. The top, which is ledged, projects 
over about an inch and forms the bed for the sand. Th e 
