264 
Solution  of  Chlorinated  Soda. 
Am.  Jour.  Pharm. 
June,  1904. 
The  amounts  represent,  respectively,  1*3  per  cent,  and  0-4  per 
cent,  of  chlorine,  with  which  we  began,  and  show  that  the  washing 
of  the  precipitate  with  the  water  needed  to  bring  the  finished 
Labarraque  to  the  required  weight,  if  carefully  carried  out,  removes 
all  but  the  last  traces  of  chlorine. 
Therefore,  whatever  loss  occurs  during  the  manufacture  of  Labar- 
raque's  Solution,  is  due  either  to  retention  of  chlorine  in  the  chlorin- 
ated lime  residue  or  to  evaporation  of  chlorine  during  the  process  of 
manufacture. 
Since  the  process  of  1880  prevented,  as  far  as  possible,  loss  by 
evaporation,  experiments  were  made  to  see  if  the  process  on  the 
whole  was  superior  to  that  of  1890. 
It  will  be  recalled  that  the  U.S. P.  of  1880  directs  mixing  of  the 
chlorinated  lime  with  water  in  a  tightly  covered  vessel  and  to  the 
paste  is  added  the  sodium  carbonate  solution  and  finally  sufficient 
water  to  bring  the  mixture  to  a  definite  weight.  Lastly,  the  clear 
solution  is  syphoned  from  the  precipitate. 
By  this  method  loss  of  chlorine  through  evaporation  is  largely 
avoided,  and  results  given  below  show  the  advantage  of  this  precau- 
tion. On  the  other  hand  the  following  figures  show  that  the  chlor- 
inated lime  is  poorly  extracted,  and  that  this  disadvantage  out- 
weighs the  advantage  gained  by  prevention  of  evaporation. 
Experiment  F. — Method  of  U.S.P.,  1880;  1,000  grammes;  made 
from  80  grammes  lime  containing  28-3  per  cent.  CI  =  22-64  grammes 
CI.  From  this  obtained  759  grammes  (724  45  c.c.)  Labarraque  and 
241  grammes  moist  lime  residue: 
1  c.c.  Labarraque  required     6*6  c.c.  —  Thio,  equalling  0*02334  gms.  CI. 
10 
5  «.«           "              "         33-2   "  ^Thio,        "  0*1174     "  " 
10 
Average — 10  c.c.  Labarraque  contained   0*23414     "  " 
"        724*45  c.c.    "              "    16-9629     "  " 
N 
2  gms.  lime  residue  required  in  c.c. —Thio,  equalling  0*03926     "  " 
10 
241  "      "          "      contained   4'73°9     "  " 
CONCLUSIONS. 
The  lime  contained   22*64     "  " 
"   Labarraque  contained   16*9629      "  " 
"  lime  residue      "    4'73°9     "  " 
