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



moisture in the air, and although the two chemical changes would run 

 on almost concurrently, yet the result would be the direct formation ol a 

 film of white lead." 



The samples of wood Nos. 1 to 10 were therefore tested to see 

 whether any fermentable sugar could be detected in them. It must, 

 however, be remembered that these woods had already produced their 

 corrosion, and according to the above theory a part, if not the whole, of 

 the fermentable sugar contained in the wood would have disappeared in 

 the process. Of the ten samples N"o. ] wild mango wood was tested most 

 carefully, and very distinct indications of a fermentable sugar were ob- 

 tained. No. 5 jalna wood and No. 9 bolos wood also gave clear indica- 

 tions of fermentable sugar, and in the case of Nos. 2, 3, and 8 as well, there 

 appeared to be traces of this substance, but in Nos. 4, 6, 7, and 10, I could 

 not detect any indications of fermentable sugar at all. 



The presence of fermentable sugar in small quantity in the wood is 

 certainly a probable cause of the formation of acetic acid, but wood con- 

 tains other ingredients besides. Thus, for instance, some kind of starchy 

 matter is a nearly constant ingredient of the stems of trees, and forms 

 the chief bulk of the reserve matter out of which leaves and shoots are 

 produced in spring. The presence of starch is also in some way con- 

 nected with the presence of sugar, for experiments have proved clearly 

 the existence of varying amounts of sugar in fruit trees, and also that 

 the sugar reaches its maximum in the spring when the starch is 

 undergoing solution. Starch also in the condition in which it is found 

 in unseasoned wood under the continued influence of heat and moisture 

 will undoubtedly suffer decomposition, and the products of decomposing 

 starch, as is well known, are of a decidedly acid character, and of the acids 

 formed, some are of the acetic series, and of these butyric acid may be 

 recognized. 



The sap of woods has also been investigated and one of the principal 

 constituents is sugar. Of the presence of carbo-hydrates other than sugar 

 no definite evidence exists, but in the cases which have yet been investi- 

 gated malic acid was also present in the sap. Now malic acid is a 

 substance on which the action of putrefactive ferments has been tried, and 

 the products of the fermentation are carbonic acid, acetic acid, succinic 

 acid, and butyric acid. 



I regret that up to the present time I have not been able to investi- 

 gate the sap of any Indian trees, nor have I found malic acid in the 

 woods experimented on, but given the probable, if not the almost certain 

 presence of small quantities of malic acid in the sap, and given the condi- 

 tions of heat, moisture, etc. to set up putrifactive fermentation in the 

 moist and unseasoned wood, the presence of all the substances necessary 

 to corrode tea-lead will at once follow. 



