Am.  Jour.  Pharm.  \ 
Sept.,  1884.  J 
Precipitates  in  Fluid  Extracts. 
455 
In  order  to  determine  the  amount  of  water  thus  passing  through  a 
liquid,  we  call  attention  to  the  following  experiment: 
A  piece  of  blotting  paper  was  placed  with  the  lower  end  in  a  solu- 
tion of  ferric  sulphate,  made  by  mixing  1  part  of  officinal  solution  of 
tersulphate  of  iron  with  32  parts  of  water.  The  separation  occurred 
as  previously  described,  and  when  the  watery  liquid  reached  the  top  of 
the  paper  (5  inches),  the  iron  solution  had  ascended  but  2  inches.  The 
paper  was  then  divided  at  the  line  of  separation  and  at  the  surface  of 
the  liquid,  the  iron  solution  in  the  lower  part  was  weighed  with  the 
paper,  and  the  water  and  paper  in  the  upper  portion  weighed.  Each 
part  was  then  dried,  and  weighed  again. 
Result. — Water  in  the  part  of  the  paper  that  contained  iron,  7 
parts. 
Water  in  the  paper  above  the  line  to  which  the  iron  had  ascended, 
7J  parts. 
In  the  same  way,  one  part  of  solution  of  tersulphate  of  iron  (ferric 
sulphate)  was  mixed  with  sixty-four  parts  of  water,  and  the  portions 
of  paper  examined. 
Result. — Water  in  the  part  of  the  paper  that  contained  iron,  4 
parts. 
Water  above  the  line  to  which  the  iron  ascended,  9J  parts. 
Thus  it  will  be  seen  that  in  the  first  experiment  the  water  that  had 
separated  was  slightly  greater  than  that  remaining  with  the  iron ; 
while  in  the  second  experiment  more  than  twice  as  much  water  escaped 
as  remained  with  the  iron. 
We  present  also  an  experiment  with  acetate  of  lead,  as  follows: 
Five  grains  of  acetate  of  lead  were  dissolved  in  one  fluidonnce  of 
water.  The  paper  was  immersed,  and  the  dividing  line  ascertained  by 
means  of  ,a  crystal  of  iodide  of  potassium.  Upon  separating  the  paper, 
it  was  found  that 
The  water  in  the  part  of  paper  that  contained  lead,  amounted  to  8J 
parts. 
Water  in  the  paper  above  the  line  to  which  the  lead  ascended, 
amounted  to  4 \  parts. 
In  the  same  way,  five  grains  of  acetate  of  lead  were  dissolved  in 
four  fluidounces  of  water: 
The  water  in  the  part  of  the  paper  that  contained  lead,  amounted  to 
5J  parts. 
Water  in  the  paper  above  the  line  to  which  the  lead  ascended, 
amounted  to  13J  parts. 
