103 
February 16th, 1874. 
VICE-PRESIDENT HGLESTON in the chair. Twenty per- 
sons present. 
Pror. Henry Wurv?z read a paper “On the Subaerial 
Oxygenation of Waters, with Experimental Illustrations,” 
of which the following is a brief abstract. 
Over two years since—in 1872—I was charged with the 
examination of a highly-important question of water-supply, 
that of the cities of north-eastern New Jersey from the river 
Passaic. Seeing the necessity, and the benefit, of some new 
and accurate micro-chemical method for determining 
oxygen in solution, I began during that summer, and have 
continued at intervals, to experiment with a new chromo-vol- 
umetric method, founded upon the use of alkaline pyrogalline 
added directly to the water. 
In the subsequent fall of the same year (1872), Schutzen- 
berger and Girardin made and published, in France, their 
proposed method with ‘“ hydrosulphite of soda.” This latter 
method was afterwards found, by its authors, to give but a 
moiety of the oxygen, and has required many modifications. 
My own new method, first published with my official report, 
in March, 1878, (see American Chemist, Sept. and Oct., 1878, 
pp. 102 and 185) I believe preferable. 
A solution of pyrogalline in alcohol, to which a drop of 
muriatic acid has been added, may be kept, for some time, in 
a state suitable for use. The water tested is first rendered 
feebly alkaline by carbonate of soda or ammonia. 
It has thus been found, in confirmation of the results of 
Bunsen (Gasometry, pp. 142-3), that the attempt to free 
water absolutely from air by boiling in the open air alone, is 
uncertain and impracticable; and water has even been boiled 
down to dryness without freeing it from a faint oxygen 
reaction. ‘lo obtain water without oxygen, oxidable agents 
added were found generally useless. Sulphide of ammonium 
was effective ; but an excess interfered with further use of 
the water. Many experiments were made with saline sub- 
stances. Common salt is capable of expelling all oxygen 
from water, this being the first demonstration of the cause of its 
preservative functions. On agitation, oxygen is not again 
