PHARMACY  OF  THE  CINCHONAS. 
411 
board  should  be  mounted  high  enough  to  admit  of  the  use  of  two 
pint  flasks  under  the  outlet.  The  percolate  should  always  be 
received  in  flasks  or  bottles  for  the  same  reason  that  the  funnel 
is  kept  closely  covered,  namely,  to  diminish  the  loss  by  evapora- 
tion in  a  slow  process  of  dropping.  Beside  this,  the  flask  may 
be  converted  into  a  sufficient  still  by  means  of  a  perforated 
cork,  india  rubber  tube,  condenser  and  an  extemporized  water 
bath.  A  piece  of  bung  cork  about  2  or  2J  inches  in  diameter 
and  an  inch  thick  is  filed  to  the  shape  of  a  truncated  cone  so  as 
to  fit  the  inside  of  the  funnel  over  the  outlet  and  lie  firmly  in  its 
place,  and  a  round  piece  of  flannel  or  blanket  is  cut  a  little 
larger  than  the  upper  surface  of  the  cork.  A  round  filter  4 
inches  in  diameter  is  cut  in  nearly  to  the  centre  all  round  by 
converging  cuts  with  a  scissors,  and  this  placed  under  the  cork 
applies  itself  closely  to  the  funnel  and  projects  above  the  cork 
all  round.  The  disc  of  blanket  is  laid  on  the  cork,  inside  this 
projecting  edge  of  the  filter,  and  then  another  filter  3  inches  in 
diameter,  cut  in  toward  the  centre  round  the  edge,  but  not  so 
deeply  as  the  first,  is  applied  on  top  of  the  blanket  and  forms  a 
kind  of  cup  to  receive  the  first  portions  of  wetted  powder.  The 
magma  should  be  poured  in  slowly  at  first,  and  into  the  centre 
of  this  little  cup,  so  as  to  press  and  flow  outward  equally  in  all 
directions,  and  thus  force  the  paper  against  the  glass  as  the  con- 
tents accumulate.  When  the  magma  rises  above  the  edges  of 
the  paper  it  may  be  transferred  more  rapidly,  and  when  all  is 
carefully  scraped  into  the  funnel  a  larger  filter — say  7|-  inches 
in  diameter  and  cut  round  the  edge — is  placed  upon  the  surface 
and  carefully  pressed  in  contact  over  the  surface  and  against 
the  side  of  the  funnel  at  the  edge.  A  funnel  and  appliances 
thus  prepared,  including  flasks  as  receivers,*  is  called  through- 
*  There  are  few  things  more  convenient  to  a  practical  pharmacist' than 
a  set  of  marked  flasks  from  two  pints  down  to  four  fluidounces,  accurately 
measured  and  marked  in  the  neck  by  means  of  a  file  or  diamond,  and 
carefully  tared  in  grains  and  the  weight  scratched  on  the  flask.  They 
may  be  accurately  marked  by  weighing  into  the  clean,  dry  flask,  coun- 
terbalanced on  a  good  scale,  recently  boiled  distilled  water  at  60°,  7291 
grains  to  the  pint.  The  French  measuring  flasks  may  also  be  used  when 
the  mark  is  higher  in  the  neck  so  as  to  admit  the  other  mark  below  for 
wine  measure.    The  pint  being  about  473  cubic  centimetres,  it  is  only 
