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



The lead lining was very carefully examined, and, though the lead 

 was much corroded in parts, it showed no sign of perforation by the corro- 

 sive action. 



The interior of the lead lining was examined and it showed no signs 

 of tarnishing or corrosion or any action whatever. 



This tea was again allowed to remain in contact with tea-lead for 

 many weeks in a moist atmosphere containing carbonic acid, and abso- 

 lutely no corrosion took place. 



Here, again, as there was no perforation of the lead lining, Dr. 

 Watt's explanation is untenable, and the corrosion was solely due to the 

 use of unseasoned wood. 



Two other cases of lead corrosion were drawn to my attention, and 

 though I regret I was unable to obtain the name of the wood of which 

 the tea boxes were made, the results of the examination are interesting. 



A case of tea marked S. (No. 1.) on being opened was found to have 

 its lead lining corroded, but not to a very great extent. The corrosion in 

 this case was of totally different nature from that in the above cases, and 

 thus while in ordinary cases the corrosion was white and to a certain 

 extent pulverulent, in the case in question the incrustation was greenish- 

 yellow in colour, and firmly adherent to the lead. The wood of the 

 box judged externally seemed well-seasoned, but on being splintered 

 emitted a " cheesy " odour, which flavour, I was told, had communicated 

 itself to the tea. The wood was examined and the odour appeared to 

 be due principally to a minute quantity of butyric acid which was 

 present. 



This wood was subjected to distillation in a current of steam, the 

 distillate placed in a bottle with tea lead hanging over it, and the bottle 

 was filled with moist carbonic acid ; on standing one side of the lead 

 became dull and tarnished, showing faint action or corrosion. 



Another chest of tea marked S. 2. showed presently similar dam- 

 age, and the wood again though apparently good and seasoned on the 

 outside, when splintered gave off a very rank and offensive smell. This 

 apparently was also due to a great extent to the presence of butyrio 

 acid. 



The wood of S. 2. was distilled in a current of steam, and the distil- 

 late placed in a bottle with tea lead hanging over it, though not touching 

 it, and treated with air containing moist carbonic acid, and after a short 

 time the lead showed distinct, though not a large amount of corrosion. 



These two cases are principally interesting because they show that 

 more than one agent may sometimes be at work in this corroding action, 

 for the results of the action in this case are markedly different from the 

 general corroding action found in the other cases. 



