WATER SUPPLY OP EASTERN AND SOUTHERN FLORIDA. 135 
depth. Water, while thus known to penetrate to a depth greater 
than a mile, probably does not reach beyond five or six miles at 
the most. The movement, as has been stated, is through natural 
openings in the rock. Pressure increases in the earth with depth, 
and it is estimated that, at a depth of approximately six miles, 
the pressure is so great that the pores and cavities of even the 
strongest rocks are completely closed,$ making it impossible for 
water to penetrate beyond this depth. Most of the water, how¬ 
ever, returns to the surface after a comparatively short under¬ 
ground course, only a small part of it reaching to this great depth. 
HYDROGEN SUEPHIDE IN UNDERGROUND WATER. 
The underground water of Florida is very generally im¬ 
pregnated with hydrogen sulphide (H 2 S), also known as sul¬ 
phuretted hydrogen, and hydro-sulphuric acid. Water containing 
hydrogen sulphide is commonly known as “sulphur water.” 
Sulphur water is especially characteristic of the areas of artesian 
flow. In those sections in which open, porous limestone is the 
surface formation, hydrogen sulphide is usually absent from the 
first water encountered, although, even here, it is found to exist 
in the water from the deep wells and in some springs. 
Source:—Hydrogen sulphide may originate, in nature, in 
any one of several ways. The following have been suggested: 
(1) The decay of organic matter containing sulphur; (2) the 
reaction of organic matter upon sulphides or sulphates; (3) the 
reaction of acids upon sulphides; (4) partial oxidization of 
sulphides; (5) steam passing over sulphur. 
The decay of organic matter is an obvious source of hydrogen 
sulphide in the underground waters of Florida. Chemical analysis 
shows that sulphur is very generally present in Florida soils,* 
and apparently invariably present in muck soils. Analyses of 
samples of peat, which is, like muck, a vegetable accumulation, 
will be found in the paper on peat deposits published in 1910. 
The amount of sulphur in the Florida peat, in the dried samples, 
varies from less than 1 per cent, to over 4 per cent. 
M. Hoskins, 16th Ann. Rept. U. S. Geol. Surv., Part I, p. 859, 1896. 
