22 



.JOURNAL OF THE 



observed the phenomenon that if the ice is struck immediately 

 above* the air, and the air thus scattered into numerous bubbles, 

 the musk-rat drowns. Having noticed an account by Professor 

 ( lomstock* of the use, by the "water boatman," of a bubble of 

 air for a tracheal gill, I would call attention to this interesting 

 feature in the physiology of respiration of the musk-rat. 



CHANGES IN BOTTLED SAMPLES OF ACID PHOS- 

 PHATE WITH CONSTANT PERCENTAGE OF 

 WATER, AND ORDINARY TEMPERATURE. 



WILLIAM H. PHILLIPS. 



Several years ago, when Chemist to the Navassa Guano Co., 

 Wilmington, N. C, it occurred to me to determine the changes 

 taking place in a sample of acid phosphate drawn directly from 

 the mixer, bottled and cooled, and examined every week for 

 twelve consecutive weeks. The results have been on hand since 

 that time, as it was hoped to supplement them by others of the 

 same kind. The opportunity of adding to them does not pre- 

 sent itself, and as they may prove of interest they are given as 

 obtained then. 



The rock used was Charleston rock of the following compo- 

 sition : 



PER CENT. 



99.07 



All of it passed a 60° seive. 



^American Naturalist. June, 1887. 



