Anafyfis of the Air* iti 
Experiment XCIV. 
March 1 2th, 4 of a cubick inch of filings 
of lron> with a cubick inch of compound 
Aquafortis, and an equal quantity of water, 
for the firft half hour abforbed 5 or 6 cubick 
inches of air j but in an hour more it had 
emitted that quantity of air 5 and in two 
hours more it again reforbed what had been 
juft before emitted. The day following it 
continued abforbing, in all 12 cubick in- 
ches: And then remained ftationary for 15 
or 20 hours. The third day it had again re- 
mitted or generated 3 or 4 cubick inches 
of air, and thence continued ftationary for 
five or fix days. 
It is remarkable, that the fame mixtures 
fhould change from generating to abforbing, 
and from abforbing to generating ftates $ 
fometimcs with, and fometimes without any 
fenfible alteration of the temperature of 
the air. 
A like quantity of filings of Iron, and 
Oil of Vitriol , made no fenfible ferment, 
and generated a very little air but upon 
pouring in an equal quantity of water, it 
generated in 2 1 days 43 cubick inches of air 5. 
and in 3 or 4 days more it reforbed 3 cu- 
1 kick 
