204 
V olumetric  Solutions  of  US.P. 
Am.  Jour.  Pharm. 
May,  1910. 
states  that  this  salt  has  a  "  tendency  to  retain  an  excess  of  acid, 
probably  tartaric,  set  free  in  small  quantity  by  the  hot  hydrochloric 
acid." 
The  more  or  less  undecided  state  of  this  question  of  the  most 
suitable  substance  for  use  in  standardizing  volumetric  solutions 
may  also  be  seen  from  the  very  large  number  of  substances  which 
have  been  proposed  for  such  use  by  different  authors.2  Thus  for 
standardizing  acids  and  alkalies,  Reinitzer  (Zeit.  anal.  Che  in.,  34, 
575)  uses  sodium  carbonate;  Grandeau  (Ibid.,  2,  426)  and  also 
Pincus  (Ibid.,  2,  426)  use  Iceland  spar;  Sorensen  (Ibid.,  40,  115) 
uses  sodium  oxalate;  Rimbach  (Ibid.,  32,  449)  uses  borax;  Hartley 
(Ibid.,  12,  89)  uses  metallic  sodium;  Seyda  (Ibid.,  39,  458)  and 
also  Weinig  (Ibid.,  32,  450)  use  ammonium  chloride ;  Knublauch 
(Ibid.,  21,  165)  uses  ammonium  sulphate;  Fessel  (Ibid.,  38,  449) 
uses  potassium  iodate;  Reichardt  (Ibid.,  13,  49)  uses  oxalic  acid; 
Ulbricht  and  Meissl  (Ibid.,  26,  350)  use  potassium  tetroxalate; 
Borntrager  (Ibid.,  25,  333)  uses  potassium  bitartrate;  Richter 
(Ibid.,  21,  205)  uses  potassium  dichromate;  Meineke  (Ibid.,  35,  338) 
uses  potassium  biniodate;  Guyard  (Ibid.,  24,  585)  uses  boric  acid; 
Petersen  (Ibid.,  41,  165)  uses  succinic  acid;  Riegler  (Ibid.,  35,  308; 
38,  250)  uses  iodic  acid;  while  Hart  and  Croasdale  (Ibid.,  31, 
I9°l  33>  455)  obtain  a  standard  sulphuric  acid  solution  by  electro- 
lyzing  pure  copper  sulphate. 
Similarly,  for  standardizing  potassium  permanganate,  Riegler 
(Ibid.,  35,  522)  uses  oxalic  acid;  Ulbricht  and  Meissl  (Ibid.,  26, 
350)  use  potassium  tetroxalate;  Sorensen  (Ibid.,  41,  169)  uses 
sodium  oxalate;  Grager  (Ibid.,  6,  209)  uses  ferrous  oxalate;  Stolba 
(Ibid.,  18,  600)  uses  lead  oxalate;  Schone  (Ibid.,  18,  137)  uses 
piano  (iron)  wire ;  Pawolleck  (Ibid.,  41,  172)  uses  ferrous  ammonium 
sulphate;  Biltz  (Ibid.,  41,  173)  uses  ferrous  sodium  sulphate;  Gintl 
(Ibid.,  6,  447)  uses  potassium  ferrocyanide ;  Wdowiszewski  (Ibid., 
41,  174)  uses  iron  oxide;  while  Erlenmeyer  (Ibid.,  18,  291) 
uses  lead  sulphocyanate.  For  standardizing  iodine  solutions,  Kal- 
mann  (Ibid.,  26,  728)  uses  sodium  sulphite;  Bobierre  (Ibid.,  8,  505) 
uses  sodium  arsenate;  Zulkowsky  (Ibid.,  41,  184)  uses  potassium 
dichromate;  Crismer  (Ibid.,  25,  553)  uses  normal  potassium  chro- 
2  A  very  useful  contribution  to  the  literature  on  this  subject,  which 
has  been  freely  made  use  of  in  this  connection,  is  a  paper  by  Vanino 
and  Seitter  in  Zeit.  anal.  C 'hem.,  41,  141-218  (1902). 
