Am.  Jour.  Pharm. ) 
May,  1881.  J 
Chemical  Notes. 
235 
tliis,  S204Na2,  is  the  correct  formula^  and  the  reaction  for  its  produc- 
tion would  be,  Zn+4NaHS03=ZnS03H-Na2S03H-Na2SA+2H20. 
— Ber.  der  Chem.  Ges.,  xiv,  p.  438. 
Organic  Chemistey. — On  the  Analysis  of  Carbon  Bisulphide  and 
of  Liquids  Containing  it. — H.  Macagno  has  sought  to  make  the  well- 
known  reaction  between  carbon  disulphide  and  alcoholic  potash  solu- 
tion available  for  the  determination  of  the  former.  In  this  case  potas- 
sium xanthate  is  formed  according  to  the  reaction 
C2H-OH + KOH + CS2=KC2H5COS2 + H2O. 
This  alcoholic  solution,  saturated  with  acetic  acid  and  treated  with  a 
drop  of  cupric  sulphate,  gives  a  brownish  precipitate  of  cupric 
xanthate,  which  quickly  changes  to  bright  yellow  flocks  of  cuprous 
xanthate.    This  salt  is  insoluble  in  water  and  in  dilute  acids. 
The  attempt  was  first  made  to  determine  gravimetrically  the  amount 
of  copper  so  obtained,  but  this  was  found  to  be  an  uncertain  method. 
The  author  succeeded  better  with  a  volumetric  process  of  determining 
the  xanthic  acid  formed  by  using  a  standard  solution  of  cupric  sul- 
phate to  pre'cipitate  it.  The  end  of  the  reaction  is  shown  by  testing 
with  a  drop  of  potassium  ferrocyanide  on  the  end  of  a  glass  rod.  If 
this  be  put  on  a  clean  i^orcelaiii  plate  with  a  drop  of  alcoholic  solution 
of  potassium  xanthate  a  perfectly  white  compound  is  formed;  but  if 
xanthic  acid  has  been  precipitated  as  cuprous  xanthate,  and  any  excess 
of  cupric  sulphate  is  present,  the  ferrocyanide  drop  becomes  red-brown 
because  of  the  formation  of  copper  ferrocyanide. 
Benjamin  Nickels,  in  the  next  number  of  the  '^Chem.  News,'' 
adapts  this  same  reaction  to  the  purification  of  commercial  benzin 
(benzol),  as  follows:  "I  usually  take  about  200  cc.  of  the  sample  under 
examination,  and  if  of  90  per  cent,  quality  add  to  it  20  cc.  (10  per 
cent.)  of  a  saturated  hot  solution  of  potassium  hydrate  in  absolute  alco- 
hol, methylated  or  otherwise.  The  mixture  is  then  subjected  to  fre- 
quent agitation  during  a  space  of  two  hours.  The  potash  compound 
of  carbon  disulphide  rapidly  forms,  and  subsides  in  feathery  groups 
with  a  silky  and  glistening  appearance.  At  the  expiration  of  the  time 
named  I  filter  off  the  benzol  so  treated  and  subject  it  to  two  washings 
with  its  own  bulk  of  water  in  a  suitable  separator ;  this  operation  com- 
pletely removes  the  alcohol  from  the  benzol.  Finally,  I  run  off  the 
Avash-water,  remove  the  benzol,  and  shake  it  up  with  a  little  powdered 
gypsum  (plaster  of  Paris),  by  which  means  the  suspended  and  dis- 
