416  Theses  on  Chemical  Subjects,         { A3^SSStSSt 
ABSTRACTS  FROM  THESES  ON  CHEMICAL  SUBJECTS.1 
By  J.  W.  Ehman. 
In  the  examination  of  six  samples  of  official  Magnesium  Carbonate 
G.  S.  DuBois  obtained  the  following  data:  Loss  on  ignition  ranging 
from  38-45  per  cent,  to  45-2  per  cent.,  the  average  being  4177  per 
cent.  Carbon  dioxide  ranging  from  33  7  per  cent,  to  37-2  per  cent., 
the  average  being  35-89  per  cent. 
The  sample  giving  the  smallest  percentage  of  residue  and  carbon 
dioxide  was  most  nearly  free  from  impurities,  showing  only  a  faint 
trace  of  iron. 
W.  S.  Thompson  experimented  with  the  cold  process  for  the 
preparation  of  Solution  of  Lead  Subacetate,  which  he  states  is  used 
by  many  pharmacists.  The  process  consists  simply  in  macerating 
lead  oxide  in  a  solution  of  lead  acetate  during  a  period  of  two  weeks 
or  more  and  decanting  the  clear  solution. 
The  best  result  obtained  was  a  preparation  assaying  only  20712 
per  cent,  lead  acetate  after  macerating  but  twenty-four  hours.  Other 
samples  macerated  a  much  longer  time  gave  still  lower  results. 
S.  E.  Thorley  compares  the  quality  of  Ammonia  Water  obtained 
from  drug  stores  with  that  obtained  from  groceries  and  department 
stores. 
Two  drug-store  samples  assayed  7-5  34  per  cent,  and  9-287  per 
cent,  of  ammonia  gas. 
Three  samples  from  department  stores  assayed  3-236  per  cent., 
6-572  per  cent,  and  12-8  per  cent,  ammonia  gas. 
Three  samples  from  groceries  assayed  1-837  Per  cent.,  2  025  per 
cent,  and  8-399  per  cent,  ammonia  gas. 
The  department-store  sample  assaying  12  8  per  cent,  ammonia 
gas  was  lound  to  be  the  only  one  containing  more  than  traces  of 
impurities,  such  as  solid  residue  on  evaporation  and  carbonate. 
Of  nine  sample  of  Sodium  Phosphate  examined  by  C.  C.  Shomo: 
One  gave  test  for  iron. 
Five  gave  slight  test  for  arsenic. 
One  gave  decided  test  for  arsenic. 
Eight  gave  test  for  calcium. 
Six  gave  slight  test  for  chlorides. 
1  The  experimental  work  embodied  in  these  theses  was  performed  in  the 
Chemical  Laboratory  of  the  Philadelphia  College  of  Pharmacy. 
