48 BULLETIN OF THE 



red-lead into peroxide upon one plate and into spojjgy lead upon 

 the other required only a small part of the oxygen and hydrogen 

 liberated by the primary current and that the remainder was me- 

 chanically held in the coatings. 



Several minor considerations support this view, and the principal 

 experiments upon which the proof should rest, viz., the liberation 

 of the gas in a vacuum or by slight application of heat in general 

 succeed. Some anomalies, however, are presented which require 

 further study, but which the author hopes soon to reconcile with 

 the theory of mechanical storing. 



A discussion followed, in which several members participated. 



206th Meeting. November 17, 1881. 



The President in the chair. 

 Thirty-eight members present. 

 The communication for the evening was by Mr. G. K. Gilbert 



ON BAROMETRIC HYPSOMETRY. 



This communication was reserved by the author, and his views 

 and investigations in connection with this subject will be found in 

 a paper contributed by him to the Second Annual Report of the 

 Director of the United States Geological Survey. 



A brief discussion ensued, and one or two points were questioned 



207th Meeting. December 3, 1881. 



The President in the chair. 



Seventy-six members and visitors present. 



Under the rules this meeting, being the next preceding the an- 

 nual meeting, was set apart for the delivery of the address of the 



