1874.| Physics. 129 
dry. This is easily accomplished by leaving it exposed to the air for some 
time, either with or without previous immersion in spirit. When the machine 
is used for the second obje&—that is, for freezing—the following directions are 
to be attended to:—Surround the freezing-box with two or three layers of 
flannel, and screw the machine to atable. Unscrew the movable bottom, or 
Fie. 2. 
Gr tes rated MEE PPLE, 
Paz 
Poy han OW 
AW Ase cae 
AS 2 
TOD 
wats 
OTEG 
DMG, 
plug (k, Fig. 3), and pour methylated spirit into the tube (c); oil the side of 
the plug; replace it, and screw it down to any desirable extent, and there 
leave it. The objeét of this is to prevent the screw from becoming fixed by 
_the freezing. The spirit which has come above the plug (xk) must be thoroughly 
VOL. Iv. (N.S.) 
