Am  Jour.  Pharra  1 
Dec,  1879.  J 
A  New  Tincture  Press. 
597 
brass  plates,  of  which  there  are  several,  with  perforations  of  different 
degrees  of  fineness,  to  suit  the  various  purposes  to  which  the  press  is 
.applied.  These  perforated  brass  plates  are  concave  transversely,  so  as 
to  form  a  continuation  of  the  surface  of  the  interior  of  the  casing. 
"The  small  end  of  the  casing  is  provided  with  means  whereby  the  out- 
let may  be  contracted  or  enlarged,  and  this  consists  of  a  brass  screw, 
which  on  being  turned  in  one  direction  diminishes  the  area  of  the  out- 
let, or  if  turned  in  the  opposite  direction  the  area  is  increased.  This 
screw  is  adjusted  in  a  detachable  ring,  which  is  screwed  on  the  small 
end  of  the  casing.  The  thread  of  the  large  tapering  screw  has  a  differ- 
ential pitch,  the  pitch  gradually  decreasing  from  the  large  to  the  small 
end  of  the  screw,  thereby  forming  within  the  casing  a  spiral  channel 
gradually  decreasing  in  size. 
The  substance  from  which  the  liquid  portion  is  to  be  separated  is 
placed  in  the  hopper,  and  the  screw  turned  by  using  the  handle  in  such 
a  direction  that  the  thread  will  have  a  tendency  to  withdraw  the  sub- 
stance from  the  hopper  and  force  it  through  the  tapering  spiral  channel 
Spiral  Channel  and  Casing  of  Tincture  Press. 
formed  by  the  screw  within  the  casing,  in  doing  which  the  pressure  on 
the  substance  will  gradually  increase  as  they  approach  the  small  end  of 
the  casing,  the  liquid  matter  thus  forced  from  the  materials  meanwhile 
passing  through  the  perforated  plate  into  the  pan  or  receptacle  below, 
whilst  the  residual  matter  passes  off  through  the  outlet. 
The  writer  has  used  this  press  with  great  satisfaction  in  pressing 
juices  from  fruits,  recovering  alcohol  and  weak  tinctures  from  percola- 
tion residues,  and  it  is  particularly  useful  with  such  drugs  as  arnica 
flowers,  hops,  etc.,  and  those  bulky,  absorbent  drugs  that  succeed  so 
well  in  wasting  alcohol.  In  expressing  opium  mass,  in  preparing 
aqueous  extract  of  opium,  it  is  very  useful  ;  the  only  class  of  drugs 
which  cannot  as  yet  be  successfully  treated  are  those  in  very  fine  pow- 
der or  such  as  are  of  a  very  sticky  or  tenacious  character. 
