ON  A  NEW  MACERATING  APPARATUS. 
175 
tinued  for  such  periods  (varying  from  1  hour  to  12  hours)  as  may 
be  appropriate  to  the  character  of  the  particular  substances 
treated. 
The  advantage  of  this  arrangement  is  that — with  little  more 
water  than  is  required  to  moisten  the  whole — each  of  the  eight 
portions  receives  eight  successive  macerations,  which  is  sufficient 
to  exhaust  even  such  stubborn  materials  as  cinchona  bark.  Other 
substances  are  exhausted  with  greater  facility  and,  of  course,  re- 
quire a  correspondingly  smaller  quantity  of  water.  If  it  is  said 
that  a  similar  result  may  be  attained  by  a  process  of  percolation 
in  a  single  vessel,  I  can  only  reply  that  I  shall  be  obliged  to  any 
gentlemen  who  will  teach  me  how  to  avoid  the  practical  difficul- 
ties of  accomplishing  this.  I  have  utterly  failed  to  do  so,  and 
out  of  these  failures,  and  by  successive  steps,  I  have  arrived  at 
the  present  expedient,  which,  according  to  my  experience,  leaves 
nothing  to  be  desired. 
Subjoined  is  a  table  showing  the  results  obtained  from  the 
treatment  of  56  lb.  of  cinchona  bark  in  the  manner  suggested. 
It  is  necessary  to  say  that  the  progressive  increase  of  density  is 
sometimes  affected  by  disturbing,  causes  (e.  g.  the  unequal  dura- 
tion of  maceration  in  certain  infusions  which  have  stood  all  night), 
and  that  the  success  of  the  operation  must  be  estimated  by  its 
general  character,  without  expecting  absolute  uniformity  in  the 
intermediate  stages. 
Specific  Gravity  of  Infusions  recovered  successively  from  Eight  Macerating  Ves- 
sels, each  containing  Seven  Pounds  Pounded  Cinchona  Bark. 
1st  Maceration  
2d  "   
4th  "   
5rh  "   
>3th  "   
7  th  «   
8th  "   
Quantity 
recovered. 
Macerating  Vessels. 
1    |  2 
3 
4 
5 
6 
7 
8 
L§  gallons  
1 
1        "  .... 
1  " 
1  « 
I  «   
I  "   
I  « 
1017-0 
1004-6 
1002-9 
1002-6 
1002-6 
1001-6 
1001-1 
1000-0 
1026  0 
1012-0 
1006-7 
1005-0 
1 003-8 
1002  3 
1002-1 
1001-8 
1034  0 
1016  1 
1011-3 
1007-4 
1005-4 
11)04-3 
1003-7 
1003  4 
1040-5 
1020-3 
1013-6 
1010-0 
1007-7 
1006-0 
1005-7 
1001-2 
1044  1 
1025-5 
1017-1 
10129 
10097 
1007-9 
1006  5 
1005-2 
1052-2 
1028-2 
1021-3 
1014-2 
1012-0 
1009-9 
1007-9 
1006-3 
1057-7 
1032-3 
10^6-3 
10203 
1014-0 
1011-6 
1009-8 
1007*8 
1060-5 
1031-0 
1029-3 
1021-5 
1016-5 
1013-3 
1010-8 
1008  0 
It  will  be  seen  that  the  exhaustion  of  the  bark  has  been  suffi- 
ciently effected  with  8|  gallons  of  water  in  lieu  of  84  gallons 
directed  to  be  used  in  the  instruction  of  the  British  Pharma- 
