162 A. Pedler — Corrosion of Lead Linings of Indian Tea Chests. [No. 3, 



The lead of the bottom of the box and of the four sides was examined, 

 and the results were similar to those above described. On all the ex- 

 ternal surfaces the lead was largely corroded, and in some parts to a 

 most excessive extent. On the inner side of the lead next to the tea, 

 except on those parts where the lead had been entirely eaten through, the 

 lead was perfectly bright and clean. 



The surface of the wood of this chest next to the lead was also 

 found to be distinctly acid to test paper. 



The lead having been perforated in this case the corrosion was still 

 open to the possibility of explanation in the manner suggested by Dr. 

 Watt, though, as described above, every appearance was against it. To 

 test this point the following experiments were made : 



Pieces of the slightly moistened wood were placed with tea-lead in 

 a large bottle with air charged with moist carbonic acid, but, after stand- 

 ing for some time, practically no corrosion of the lead appeared. 



Some of the tea was taken under similar circumstances to the above 

 and placed with tea lead ; the lead remained perfectly bright and uncor- 

 roded. 



Some of the wood of the box was distilled in a current of steam, 

 and the distillate tested by placing some of it at the bottom of a bottle ; a 

 piece of tea-lead was then hung in the bottle, so that it did not touch the 

 liquid, and the bottle was repeatedly filled with air charged with moist 

 carbonic acid.* The tea-lead was very distinctly corroded on standing. 



Some of the tea was also distilled in a current of steam and the distil- 

 late treated as in the last experiment, but it had no corrosive action what- 

 ever on the tea-lead. Some pieces of the wood of this box were placed with 

 water and tea-lead hung over it, but not so as to touch it, and exposed 

 to the air. The lead was corroded very rapidly. Some of the tea was 

 taken also placed in water and tea-lead hung over it, but not so as to touch 

 it. For a long period there was no corrosion of the tea-lead, but after the 

 tea had become mouldy and had decomposed for some time, then corrosion 

 Bet in, but very much later than in the previous experiment with the 

 wood. 



It was highly probable, then, from these experiments that the wood 

 was the source of the corrosion and certainly not the tea. 



Examination of Case No. 2. This was a half chest containing 

 40Ibs. of pekoe souchong tea, and made entirely of wild mano-o wood 

 which was thoroughly dry and well-seasoned, but af fcer the tea was pack- 



* The presence of the carbonic acid and moist air is a necessary condition to 

 produce rapid action on lead in the presence of certain exciting agents. It is also the 

 the condition which a chest of tea would probably be subjected to in the hold of a 

 ship. 



