496 
Fusion  of  Metallic  Arsenic. 
(  Am.  Jour.  Phaum, 
\     Nov.  1,  1872. 
have  found  that  50  parts  of  impure  metal  required  from  3*5  to  4  of 
cyanide  with  1  of  sulphur.  If  a  deficiency  of  cyanide  be  used,  sul- 
phide of  bismuth  is  formed,  thus  involving  a  second  fusion,  or  entail- 
ing a  serious  percentage  loss  of  metal  in  the  button,  but  this  need  not 
happen  if  the  above  precautions  be  observed. 
A  weighed  portion  of  the  button  first  obtained  was  dissolved,  and 
after  the  separation  of  Bi.  as  before,  treated  with  H2S,  but  not  a  trace 
of  Cu.  was  revealed.  Excess  of  ammonia  to  the  acid  solution  did  not, 
produce  the  slightest  coloration,  nor  did  any  of  the  usual  specific  tests 
for  Cu.  indicate  the  slightest  trace  of  that  metal.  The  coppery  bis- 
muth had,  therefore,  been  completely  freed  from  the  Cu.  by  the  very 
simple  process  of  Tamm. 
Since  writing  the  above,  I  have  met  with  a  paper  by  Mr.  Schacht,* 
wherein  he  gives  the  results  of  some  of  his  experiments  in  removing 
Cu.  from  Bi.  by  fusion  with  nitre.  It  is  stated  that  the  whole  of  the 
Cu.  cannot  be  removed  by  the  B.  P.  process.  This  statement  is  doubt- 
less correct ;  repeated  fusions  are  certainly  necessary.  The  process  of 
Tamm,  so  far  as  my  experience  goe3,  is  unquestionably  by  far  the  more 
perfect,  and  I  think  leaves  nothing  to  be  desired.  A  little  sulphur 
may  be  left  with  the  metal,  but  this  is  practically  of  no  consequence. 
With  regard  to  percentage  loss,  Mr.  Schacht  states  "  that  the  loss 
yaries  with  the  duration  of  the  process  from  7  to  17  per  cent."  In 
his  experiment,  1000  grains  of  coppery  bismuth,  after  three  fusions, 
with  nitre,  lost  170  grains,  and  ''still  yielded  abundant  evidence  of 
copper."  In  this  respect,  therefore,  as  well  as  in  the  more  thorough 
efficiency,  the  process  of  Tamm  may  well  supersede  that  of  the  pres- 
ent Pharmacopoeia. — Pharm.  Journ.  and  Trans.,  Sept.  14,  1872. 
ON  THE  FUSION  OF  METALLIC  ARSENIC.f 
By  J.  W.  Mallet,  Ph.  D.,  M.  D. 
Professor  of  Pure  and  Applied  Chemistry,  University  of  Virginia. 
Experiments  on  this  subject,  made  by  Mr.  Dunnington  and  Mr. 
Adger,  students  in  the  Laboratory  of  the  University  of  Virginia,  un- 
der the  author's  directions,  were  described.  These  experiments  had 
been  undertaken  in  view  of  the  generally  repeated  statement  that  ar- 
*  Pharmaceutical  Journal,  April,  1868. 
fRead  before  the  British  Association,  Brighton  Meeting,  Section  B. 
