136 
FLORIDA STATE GEOLOGICAL SURVEY. 
Hydrogen sulphide is formed in connection with the decay of 
eggs. In this case the albumen of the egg, according to Ostwald, 
contains the sulphur.f H 2 S is also found escaping from sewer 
drains and cesspools, and is formed, during the decomposition, 
both of animal and vegetable substances. The H 2 S occurring in 
shallow springs from marsh lands is, doubtless, supplied largely 
from organic material. 
The sulphur in soils is, probably, often present as sulphates. 
Thorpe states that the decay of organic matter in contact with 
sulphates results in the formation of H 2 S 4 The reaction in this 
case, probably, results from reducing properties of decaying 
organic matter, the sulphates being first reduced to sulphides, 
according to the following reaction: Na 2 S O4-I-C2 (carbon of 
organic matter) = 2 CC) 2 -f-Na 2 S. The sulphide is then acted upon 
by the carbonic acid to form H 2 S as follows: Na2S+H2C03=: 
H2S+Na2C03. The reaction of organic matter upon the sulphides 
is regarded, by Van Hise, as another important source of H 2 S in 
underground water.* * 
The formation of hydrogen sulphide, as a result of the action 
of acids upon metallic sulphides, is one of the most familiar of 
laboratory experiments. This suggests the possibility of the 
formation of this gas, as the result of the action of acid's upon 
metallic sulphides, contained in the rocks. Sulphides, especially 
those of iron, are widely scattered in the earth’s crust, and occur 
in sufficient quantity to account for the formation of H 2 S gas in 
water. Hydrogen sulphide is a weak acid, and its salts are de¬ 
composed by a stronger acid. Sulphuric and other mineral acids 
should certainly react upon sulphides liberating H 2 S. Carbonic 
acid, when abundant, reacts upon alkali sulphides to produce 
hydrogen sulphide. It is true that the alkali sulphides are 
normally not abundant in the crust of the earth. Stokes has 
shown, however, that the reaction of sodium carbonate within the 
^Bulletin 43, Florida State Experiment Station, pp. 653, 657, 659, 1897. 
fOstwald, Principles of Inorganic Chemistry, page 274, 1904. 
^Dictionary of Chemistry, Vol. Ill, p. 697, 1900. 
*A Treatise on Metamorphism, Mon. XLVII U. S. Geol. Surv., p. 
1112, 1904. 
