1885.] A. Pedler — Corrosion of Lead Linhigs of Indian Tea Chests. 175 



In the case of an unseasoned wood, the sap will still be present in 

 small quantity, and thus the presence of acetic acid, butyric acid, etc., may 

 be readily accounted for, if the wood is placed under circumstances of heat 

 and moisture favourable to the production of fermentation. 



The conclusions that my experiments have led me to form are as 

 follows : — 



1. That tea properly manufactured in the ordinary way has no 

 power to corrode lead. 



2. That if unseasoned and damp wood is used for the manufacture 

 of the tea boxes, corrosion of the tea lead is, under favourable circum^ 

 stances, almost certain, but that some varieties of wood act more violently 

 than others. 



3. That even if seasoned wood be used to make the tea boxes, and if 

 it be allowed to become saturated with water, and then placed in favour- 

 able circumstances of heat and moisture, corrosion of the tea lead may 

 occur, though not to so great an extent as if unseasoned wood had been 

 used. 



4. That the active agent does not exist ready formed in unseasoned 

 wood, but is produced by a secondary action from the constituents of the 

 wood. 



6. That the corrosion is not usually due to contact action between the 

 lead and the wood, but that a volatile substance is gradually produced 

 from the unseasoned wood. 



6. That the corroding agent is usually acetic acid in the presence 

 of moist air and carbonic acid, but that other acids of the same series are 

 sometimes produced, and also act on the lead, and in the case of butyric 

 and valeric acids a greenish yellow incrustation is formed differing en- 

 tirely from the whitish or yellowish incrustation produced from acetio 

 acid. 



7. That the acetic and other acids are produced by the decomposi- 

 tion (probably by a kind of fermentation under the influence of heat and 

 moisture, and perhaps started by decomposing nitrogenous matters) of 

 certain substances which are known to be present in woods. Such bodies 

 are fermentable sugars, starchy matters, malic acid, etc. 



8. That the lead linings of the tea chests having been corroded and 

 perforated by the corroding action of these acids in the presence of moist 

 air and carbonic acid, the tea can easily take up the disagreeable odour 

 which the wood itself will possess, after it has undergone the change 

 in which acetic and butyric acid, etc., are formed, and thus the quality 

 of the tea will be deteriorated. 



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