21 8  Preparation  of  Compressed  Tablets.  {^S:^m' 
pound  might  require  something  to  prevent  sticking,  10  to  20 
tablets  would  require  nothing.  Wetting  with  alcohol  and  drying 
will  almost  always  leave  the  mass  grainy.  It  does  not  matter  how 
fine  your  material  is,  all  you  want  is  that  it  will  tumble  and  not 
hold  together  on  account  of  the  moisture  in  it.  I  might  talk  for  a 
week  about  material ;  but  I  wish  to  say  something  about  how  to 
make  the  tablets. 
In  the  first  place,  do  not  get  the  fidgets,  see  that  everything  is  in 
place  and  that  your  machine  is  clean.  Choose  the  set  of  dies 
required  ;  and  in  this  machine  designed  especially  for  retail  drug- 
gists, you  will  find  by  lifting  a  small  shaft  and  removing  a  pin,  you 
can  take  off  the  feeder.  Turning  a  few  turns  on  this  thumb  screw 
you  can  pull  out  the  die  holder;  while  this  is  out  you  can  see  if  the 
internal  part  of  the  machine  is  clean.  The  die  holder  being  out, 
put  in  a  top  punch  of  the  size  you  wish,  put  the  die  into  the  die 
holder,  insert  the  bottom  punch,  put  in  the  die  holder  with  its  con- 
taining die  and  punch,  fasten  into  place  by  turning  thumb  screw, 
slip  on  the  feeder,  drop  the  small  vertical  shaft  into  place,  and  you  are 
ready  for  work.  Weigh  out  the  quantity  of  one  tablet,  pour  it 
into  the  die  and  screw  up  the  bottom  punch  until  the  material 
comes  even  with  the  plate.  Turn  on  the  pressure,  and  when  the 
top  punch  is  at  its  lowest  depth,  turn  the  knob  at  the  top  of  the 
eccentric  strap  until  you  feel  the  pressure.  Make  2  or  3  tablets  to 
see  whether  the  weight  is  all  right,  then  put  on  more  pressure  if 
necessary  and  finish  your  work.  The  first  tablets  should  not  be 
pressed  much ;  when  you  are  sure  of  your  weight,  you  can  powder 
the  trial  ones  between  your  fingers  and  return  to  the  feeder.  The 
small  cup  should  be  used  in  making  up  small  quantities.  Put  it  in 
by  taking  off  the  top  of  the  feeder  and  simply  putting  the  cup  in 
its  place  ;  the  motion  of  the  feeder,  in  going  backward  and  forward, 
will  cause  the  material  to  drop  into  the  die  ;  the  remnant  of  one  or 
two  tablets  can  be  brushed  into  the  die  and  there  is  no  need  of 
wasting  any  material  at  all.  The  feeder  is  so  constructed  that 
there  can  be  no  leakage  from  beneath  the  feed.  The  lower  punch 
is  so  constructed  that  there  is  the  least  amount  of  friction  possible. 
One  great  fault  in  making  tablets  is  in  using  too  much  pressure, 
running  at  the  rate  of  60  per  minute,  the  pressure  should  scarcely 
be  felt  on  small  tablets  ;  but  by  taking  a  tablet  between  the  fingers  a 
little  experience  will  tell  you  whether  to  put  on  or  take  off  pressure, 
