1885.] A. Podloi* — Corrndon of Lead Lining fi of Indian Tea Chests. 159 



XIII. — Memorandum on the CorroAon of the Lead Lini7igs of Indian Tea 



Chests. — By Alex. Pedler, F. C. S., Frofessor of Chemistry 



in the Presidency College, Calcutta. 



During the last few years rather numerous instances have happened 

 of chests of tea, apparently prepared and packed in the usual way in the 

 tea districts of India, reaching Calcutta or England in a damaged condi- 

 tion ; the damage consisting in the partial corrosion, and sometimes 

 almost total destruction of the lead linings of the chests, and in the 

 deterioration of the quality of the tea itself. 



At the request of the Indian Tea Association I undertook some time 

 since to make some experiments in order to ascertain the cause of this 

 corrosion, and though my experiments have not yet been completed so 

 far as I could wish, they are sufficiently far advancd to enable me, at the 

 urgent request of the Indian Tea Association and of the the Bengal 

 Government, to write a preliminary memorandum. 



The previously published literature on this subject is remarkably 

 meagre, and it may be summed up in a few words. On the other hand, 

 there is reason to believe that there is a large accumulation of unpub- 

 lished evidence on this subject, and it is desirable that some steps should 

 be taken to collect and collate the mass of evidence which must have 

 accumulated in the hands of the various agents of tea gardens, and in 

 the hands perhaps of the more experienced planters. 



The first experimental enquiry as to the corrosion of the lead linings 

 of Indian tea chests and its cause which I can find published in 

 scientific periodicals appears to have been carried out some time previous 

 to 1883 by Dr. Wigner, who was then President of the Society of Public 

 Analysts in England. He published, in Vol. II of the Journal of the 

 Society of Chemical Industry, a paper entitled " The packing of sub- 

 stances of delicate odour such as Tea, &c. "*, in which he describes his 

 experiments, made during the previous five or six years, in certain cases 

 of corrosion of tea-leads in boxes made of Indian woods, the consignments 

 of tea coming principally from Assam. The conclusions at which he 

 arrived were that the corrosion was due to the wood used in the boxes, 

 and his theory, though he did not adduce any specific facts as to the 

 cause of the corrosion, was that the wood must have in some way 

 generated acetic or other volatile acid, which, in the presence of carbonic 

 acid and moist air, would account for the corrosion of the lead. My 

 experiments have in almost all respects confirmed this theory. 



The next contribution to our knowledge of this subject which I can 



* Journal of the Society of Chemical Indastrj, Vol. II, p. 256. 

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