PHARMACEUTICAL APPARATUS. 
315 
zontal direction on ledges within the box ; g is a drawer benealh 
to catch the powder as it passes, and h a tightly fitting cover, 
which prevents the escape of dust without impeding the motion of 
the sieve. It will be at once perceived, that on turning the crank, 
the horizontal bar will be forced back and forth by the zig zag di- 
rection of the groove, which motion it communicates to the sieve ; 
each revolution of the crank causing six distinct jerks of the 
sieve. There are seives of two or three sizes, so as to yield powder 
of different degrees of fineness. 
Rotary Pill Machine. — This apparatus is intended as an 
expeditious means of making quantities of pills. It consists essen- 
tially of a pair of rol- 
lers of equal diameter 
moved towards each 
other, above, by accu- 
rately made cogs at- 
tached to the end of 
each by means of a 
crank attached to the 
axel of one of them. 
The surface of each rol- 
ler is penetrated at reg- 
ular distances with he- 
mispherical cavities, ar- 
ranged with mathemati- 
cal precision, in such a 
manner that when the 
rollers press together, each successive row of cavities m eeLO liiC 
corresponding one on the other roller, so that at the point of con- 
tact a row of spherical moulds is produced. The rollers are sup- 
ported firmly on a cast-iron base and supports. The rollers are ap- 
proximated, when required, by lateral screws passing through the 
sides of the supports not seen in the figure. In using this machine 
the pill mass should have a uniform consistence of a certain firm- 
ness, not too tough or adhesive. It should be formed into ribbon- 
like strips, about one-eighth of an inch in thickness, and while 
one person turns the crank, which requires a considerable degree 
of force, another feeds the rollers as they gradually draw in the 
