Peters and Sauchelli — Succinic Acid as a Standard. 245 



type described by Bobbins* in the article following was used. 

 Temperature Regulator. — A conductivity cell was placed in a 

 12-liter heavy glass tank. The temperature, so controlled, was 

 13°. Bridge. — A 100 cm wire calibrated by the method of 

 Strouhal and Barus. 



Standards. 



Succinic Acid. — This was made in strengths as required by 

 weighing out the desired portions. A mold invariably devel- 

 oped in the succinic acid solution. This necessitated working 

 with fresh solution at each trial. However, several titrametric 

 trials made on a solution of acid containing mold showed that 

 the solution did not undergo change in normality in a few 

 days or, if it did, the change was so small as to be undetecta- 

 ble with the methods employed. Ammonia. — The ammonia 

 either was compared with hydrochloric acid which was gravi- 

 metrically standardized as silver chloride, or was compared 

 with sulphuric acid which was standardized with carbonate of 

 soda made from the acid carbonate by careful heating to 300°. 



Procedure. 



Electro-titrametrically . — The tip of a burette being inserted 

 between the electrodes, a measured volume of ammonia water 

 was drawn off. Then a measured quantity of succinic acid 

 solution was drawn from a similar burette and the solutions were 

 thoroughly mixed. This was accomplished by sucking the 

 contents of B up into M by means of mouth aspiration applied 

 to a soda-lime tube attached at S.f Three or four applications 

 of suction were sufficient to mix the liquids as evinced by the 

 lack of change in the bridge readings. The bridge was then 

 balanced. Further portions of the succinic acid solution being 

 added, the process was repeated until several points each side 

 of the neutral point were obtained. 



Pesidts. 



The results are collected in Table I which follows, and also 

 are shown in the accompanying graphs. 



These figures show that when 10 cc of ammonia were intro- 

 duced into the cup and successive portions of succinic acid, 9 

 grams to the liter, JN". 0*1525, were added, the results of the 

 duplicate determinations, given in I and II of Table I, indi- 

 cate that 8 - 13 cc of succinic acid were required to neutralize 



*This Journal (4), xli, p. 249, 1916. 

 flbid., p. 250. 



