12 On Volcanos and Earthquakes. 
The weight of the dry residuum from a like quantity of 
water was | 
ater has been repeatedly taken from the different wells, 
as it flowed in from the earth, and where it could not possi- 
bly have been in contact with the i iron of any part of the 
pumping machinery, and, on scraping into it some nutgall, 
with a piece of broken glass, there has Baca observed, in a 
short time, a change from mares ereherems to a purple co- 
lor, which soon became green, and finally of a reddish brown ; 
and, after standing two or ites weeks, there was a 
brown deposit that covered the bottoms of the tumblers in 
which the experiments were made. 
Bubbles of carbonic acid are continually escaping, pee 
frequently i in great quantity, from the brine of the springs 
“AE one of the plants that frequent salt marshes on the sea. 
shore was observed growing abundantly at Salina, Mr. Smith 
was requested to examine it for iodine—which substance 
_ did not appear on the addition of sulphuric acid and solution 
of starch to the fluid bittern, or the solid residuum which it 
afforded by evaporation. The follo ipa is Mr. Smith’s re- 
mark in a P.S. to his communication.— 
I have made, and repeated, the experiment requested by 
you, when here, with the samphire, of which the quantity 
employed yielded half a peck of ashes. The product was 
e of 
ae muriate of soda, without» Sas appearance 
iodin 
is Til. “FS othens on Volcanos and Earthquakes ; by 
Pam Du Commun, of the Military Academy at West- 
‘Tar air Re atmosphere at the surface of the earth, will 
support, in barometer tubes, mercury at 30 in ches, 
: = water at : te ’ 
a water at about 32 feet. 
It is eight hundreds =e twenty-eight times lighter than 
water, or 00120 : 1. 
And because fresh water teto sea water as 16003 is to 1029, 
so air is a auodee = fifty-three tints oe than sea 
water, or 0,00118 : 1. 
