1885.] A. Pedler — Oorrosion of Lead Linings of Indian Tea Ohests. 171 



Acetic acid in very small quantity was tested in the same way ; the 

 lead in a few hours was entirely covered with a film of white lead ; in 

 twenty-four hours the greater part of the lead had been corroded and 

 destroyed, and in thirty-six hours the lead had been entirely eaten 

 through, and converted into white lead with a small quantity of lead 

 acetate present in it as usual. 



Propionic acid, the third member of the series, after a few days had 

 corroded the lead rather rapidly, and the greater part of the lead was 

 entirely eaten through. The greater part of the lead was converted into 

 the carbonate, though some soluble propionate was found. 



Propionic acid then acts on lead in a manner analogous to acetic acid. 



Butyric acid was tried in a similar manner, and after standing some 

 days the lead was more than haK eaten through, and the surface was 

 covered with a moist yellowish green deposit. The lead was to a consi- 

 derable extent converted into lead butyrate, but lead carbonate was also 

 present in small quantity. Butyric acid therefore acts on lead in a man- 

 ner analogous to acetic and propionic acid, but far more feebly. 



Valeric acid, the fifth and last member of this series tried, caused a 

 large amount of action on the lead, the surface of which became covered 

 with a greenish yellow incrustation, and on some parts of which consi- 

 derable amounts of crystalline scales were present. A large part of the 

 corrosion was due to the formation of lead valerate, but a small amount of 

 carbonate was also present. 



Valeric acid therefore acts on lead in the same way as acetic, propio- 

 nic, and butyric acid, but the production of the carbonate is much more 

 feeble. 



A most interesting point in the case of the last two bodies, butyric 

 and valeric acids, is that the incrustation on the lead was strikingly ana- 

 logous to that found in the rarer form of corrosion in tea chests as de- 

 scribed under the cases S. 1. and S. 2. 



Other but less volatile organic acids, such as Benzoic acid etc., were 

 tried, but they produced no appreciable action on lead. 



Hydrochloric acid in the same way was tried and the lead surface be- 

 came covered with chloride of lead with which a minute trace of carbo- 

 nate was mixed. 



Nitric acid tested in the same way caused very rapid corrosion, the 

 product of the action appearing to be either a basic nitrate or a mixture 

 of nitrate and hydrate. 



Ammonia acted on the surface of the lead to a small extent, and con- 

 verted it partly into oxide. 



A series of alcohols, consisting of methylated ethyl alcohol, ethyl 

 alcohol, propyl alcohol, butyl alcohol and amyl alcohol, was tried, but 

 beyond a slight superficial action no corrosion was found to take place . 



