Am.  Jour.  Pharm.  ) 
November,  1920.  ) 
Current  Literature. 
833 
reappear  again  on  heating.  If  the  mixture  be  boiled  a  few  minutes, 
the  color  will  turn  a  deep  dark  green,  which  will  become  a  light 
yellow-green  on  cooling.  If  to  the  cold  yellow-green  solution  an 
equal  volume  of  sulphuric  acid  be  added  so  as  to  form  2  layers,  the 
blue  color  will  again  appear.  It  is  believed  that  all  these  reactions 
taken  together  are  characteristic  of  oxalic  acid  alone. 
This  test  may  be  made  sensitive  to  one  milligram  if  the  dry 
unknown  substance  be  warmed  with  2  drops  of  a  10  per  cent,  aqueous 
resorcinol  solution  and  the  sulphuric  acid  added  drop  by  drop.  The 
blue  color  then  appears  immediately.  For  very  dilute  solutions  of 
oxalic  acid  or  its  salts,  it  is  best  to  evaporate  to  a  concentration  of 
about  10  per  cent. 
If  interfering  substances  are  present  the  oxalic  acid  may  be  pre- 
cipitated in  ammoniacal  solution  as  the  calcium  salt,  washed  with 
water,  and  the  test  applied  directly  to  an  aqueous  suspension  of  the 
salt. 
CURRENT  LITERATURE. 
TRADE  INTEREST. 
AivSATiAN  Potash. — The  French  Minister  of  Agriculture,  in  a 
notice  published  in  the  J  our  nee  Industrielle,  reminds  persons  inter- 
ested in  the  purchase  of  Alsatian  potash  salts,  that  trade  in  this 
commodity  is  now  free.  He  adds  that  orders  for  potash  are  no 
concern  of  his  Department,  and  that  they  should  be  sent  either  to 
Mulhouse,  or  to  the  various  representatives  of  the  Societe  Com- 
merciale  des  Potasses  d' Alsace.  Whereas  before  the  war  the  con- 
sumption of  pure  potash  in  France  did  not  exceed  37,000  tons  a  year, 
the  mines  of  Alsace  were  able  to  send  to  France  no  less  than  47,000 
tons  of  pure  potash  in  the  year  1919,  and  30,000  tons  in  the  first  half 
of  the  present  year.  Many  orders  which  were  given  sometime  ago 
have  not  yet  been  delivered,  but  the  Minister  of  Agriculture  has 
been  able  to  arrange  that  a  sufficient  number  of  trains  shall  be  placed 
at  the  disposal  of  the  mines,  to  insure  the  delivery  of  5,000  to  8,000 
tons  of  pure  potash  a  month.  It  is,  therefore,  to  be  presumed  that 
delays  in  delivery  will  no  longer  occur.  (From  The  Pharm.  Jour. 
&  Pharm. y  Sept.  4,  1920.) 
