422 
Bismuth  Subnitrate. 
( Am.  Jour.  Pharru. 
t      August,  1896. 
It  is  known  in  England  under  the  name  of  white  deal. 
In  recent  times  the  wood  of  the  Norway  spruce  has  come  into 
extensive  use  for  manufacture  into  paper.  The  exports  of  wood 
pulp,  mostly  from  this  tree,  from  Norwegian  ports — part  of  which 
is  Swedish  produce — amounted,  in  1893, t0  230,000  tons. 
{To  be  continued.) 
ON   THE   CHEMICAL  COMPOSITION  OF  BISMUTH 
SUBNITRATE. ..... 
BY  IyYMAN  F.  Kebt_er. 
Having  been  investigating  the  chemical  composition  of  the  bis-  _ 
muth  subnitrate  in  our  markets  for  some  time,  the  writer  naturally 
read  the  excellent  communication  on  this  subject,  by  the  late  Dr. 
Curtman,1  with  much  interest.  Since  the  results  obtained  by  the 
writer  differ,  in  some  respects,  from  those  reported  by  Dr.  Curtman, 
it  will  be  interesting  to  record  them.  For  conditions  affecting  the 
composition  of  this  article  the  reader  is  referred  to  Dr.  Curtman's 
paper,  Dammer's  "  Handbook,"  or  any  other  extensive  chemical 
treatise. 
The  first  obstacle  met  with  in  the  work  was  to  differentiate 
between  the  amount  of  moisture  mechanically  retained  and  the  per 
cent,  of  chemically  combined  water.  The  Pharmacopoeia  states : 
"  When  heated  to  1200  C,  the  salt  loses  water  (between  3  and  5  per 
cent,  of  its  weight)."  No  time  is  specified.  Is  it  to  be  understood 
that  this  indicates  the  mechanically  retained  moisture  or  both  ?  In 
order  to  obtain  some  data  on  the  subject,  the  following  experiments 
were  made  :  A  weighed  quantity  of  good  bismuth  subnitrate2  was 
placed  in  a  desiccator  containing  strong  sulphuric  acid,  and  the  total 
percentage  of  loss  for  the  entire  time  noted  every  twenty-four  hours> 
with  one  exception:  1st  day  087,  2d  0-96,  3d  096,  4th  1-19, 
5th  1-19,  7th  1-26,  8th  1-30,  9th  130,  10th  1-30,  nth  131, 
12th  1-32. 
Next,  given  weights  of  ten  samples  were  simultaneously  dried  in 
an  air  bath,  at  900  C,  for  2,  8  and  24  hours,  and  the  total  loss  noted 
at  the  end  of  each  interval  of  time.    Drying  was  then  continued  at 
1  1896,  Am.  Druggist,  28,  8  ;  Pharm.  Era,  15,  43  ;  Pharm.  Reviews  i*»  I2- 
2  No.  9  in  tables  below. 
