14 
PHARMACEUTICAL  GLEANINGS. 
to  be  described,  is  exactly  that  given  to  the  pestle  by  a  skilful 
manipulator  when  operated  by  hand. 
Fig.  IS. 
«  The  pestle  is  secured  at  the  top  by  a  lever,  to  which  any 
weight  may  be  applied ;  the  gearing  for  working  the  same  is 
driven  by  means  of  a  bevel-toothed  gear,  on  the  main  driving 
shaft,  which  is  provided  with  a  winch  handle.  The  mortar  being 
placed  in  front  of  the  machinery,  removes  the  possibility  of  dirt 
from  the  friction  of  the  wheels  falling  into  it ;  hence  it  will  be 
found  of  great  advantage  for  all  kinds  of  salts,  choice  colors, 
mercurial  preparations,  printers'  ink,  &c.  The  pestle  may  be  re- 
moved by  simply  taking  out  a  screw  from  the  driving  shaft. 
"  The  amount  of  labor  saved  is  considerable,  as  the  hardest 
and  most  difficult  substances  may  be  ground  by  this  machine, 
worked  by  hand,  as  effectually  as  by  the  most  powerful  machine- 
ry. On  a  large  scale,  driven  by  steam,  it  will  be  found  to  do  more 
work  with  less  power  than  any  mill  hitherto  erected.  The  pes- 
tle traversing  over  a  different  surface  every  time,  removes  the 
necessity  of  scrapers  to  keep  the  material  constantly  acted  upon. 
"  Among  the  articles  which  are  readily  ground  by  it  may  be 
mentioned :  ginger,  mustard,  salts  of  all  kind,  cream  of  tartar, 
