viii, a. 6 Editorial 441 



charged as rapidly as possible. The relatively large amount of 

 free acidity thus produced may be judged from its effect on a 

 bronze propeller shaft used on one of the ship's small launches. 

 The portion exposed to the water Was reduced to about one-half 

 its original diameter (Plate I). It should be remembered that 

 this was corroded, not in a protected bay or harbor, but in the 

 open sea. 



It is very probable that the many instances of deterioration 

 known to take place during the shipment of copra are repeti- 

 tions of the above conditions on a small scale. Sea captains 

 have frequently informed me that it was always considered un- 

 wise to remain long in holds filled with copra. This finds its 

 explanation in the slow production of toxic hydrogen sulphide. 

 The rate of bacterial action depends upon the care used in pre- 

 paring the copra and the degree of moisture present. With 

 carefully dried copra, the deterioration due to hydrogen-sulphide- 

 producing and other organism will be at a minimum, although 

 it is doubtful if it can be entirely avoided until more satis- 

 factory and sterilizing methods of preparation are generally 

 employed. 



David S. Pratt. 



123668 5 



