MINERAL AND GASEOUS SPRINGS. 
313 
several pounds in the space of a few feet. The decomposition of this rock, beyond ordinary 
exposure, from the percolation of water from above, will produce precisely the materials with 
which the spring is charged; and there can remain no reasonable doubt of this being their 
origin generally, or even universally in the Fourth District. 
The quantity of this gas is not surprising, when we reflect that a single ounce of the bi- 
sulphuret of iron, if decomposed and its sulphur united with hydrogen, will produce more 
than two hundred cubic inches of the gas. This is a large amount of this noxious vapor from 
so small a quantity of the material; the decomposition of a few pounds of pyrites will be 
sufficient to supply an ordinary sulphur spring for several months ; and in the more copious 
springs, it must be recollected that there are large surfaces exposed to the action of air and 
water. 
The increased temperature noticed in all these springs may be due to chemical decomposi¬ 
tion and recomposition, so that more caloric is evolved from the solids formed than is required 
for the production of the gas. Their great uniformity of temperature in widely different 
positions, wrnuld indicate the cause to be in chemical action, rather than to proceed from any 
deep-seated and general source, as we may suppose is the case with the thermal springs 
which evolve only nitrogen. 
The same views will apply to those springs evolving carburetted hydrogen; the most co¬ 
pious being in the highly bituminous shales of the Portage and Chemung groups, while it is 
produced in smaller quantities from the lower rocks. Its origin is thus satisfactorily proved, 
and we have the same evidences regarding the production of the hydrosulphuretted springs. 
In the same rocks in the eastern part of the State, which at the west give origin to the car¬ 
buretted hydrogen and petroleum, that substance is not manifest, and there are no springs of 
the kind. Again, the rocks most productive of the hydrosulphuretted springs are equally 
charged with sulphuret of iron in the eastern part of the State, and give origin to as copious 
and strongly charged waters as at the west. 
It is true that in some places carburetted hydrogen is very abundant at points where there 
has been a slight disturbance or uplifting of the strata ; but it appears to be in consequence of 
finding more rapid egress through the numerous joints, rather than in any manner to depend 
on such fracture for its origin; and in many of the most copious ones, no such marks of 
disturbance are visible. 
On September 1st, 1841, the temperature of the Avon springs was 50° Fahrenheit; the 
lower one a fraction less. The upper spring discharges about eight or ten gallons per minute ; 
the lower one, fifty-four gallons per minute. 
The temperature of the several springs at Manchester, which are the most copious of any 
in the district, and from which a larger quantity of gas is evolved than in any other, is 50° 
and 51° of Fahrenheit’s scab. The quantity of water is much greater than at Avon. 
The situation of the Avon springs is illustrated by the following woodcut; 
[Geol. 4th Diet.] 
40 
