CHAPTER XV. 
The Sulfid Group. 
Sulfid waters, or those giving off free hydrogen-sulfid gas, are 
very widely distributed all over the world. This gas, which is 
considered of great value by many physicians as a constituent 
of mineral waters, often issues from the earth in the vicinity of 
semi-active volcanoes, and the chemist readily understands how 
it may be set free by the action of hot water on sulfids. Or- 
ganic matter, which has a tendency to reduce sulfates to sulfids, 
often assists very much in its formation. The therapeutic ac- 
tion of this gas has already been discussed (see pp. 65-67). 
These waters may contain not only the free hydrogen-sulfid 
gas, but the sulfids, sulfhydrates, and perhaps thiosulfates 
(hyposulfites). The therapeutic action, as has been noticed, 
is supposed to be different when we have a solution of a sulfid, 
etc., from the action of the gas simply dissolved in water. 
The sulfur waters of Kansas are not numerous, but some of 
them may become of importance. Several of these waters are 
those that supply the cities of the southeastern part of the state. 
Here the surface-waters are very unsatisfactory on account of 
the proximity of coal-mines, and the deep well-waters are the 
only supply available. As the deep-well waters are allowed to 
stand exposed to the air oxidation takes place, and a white deposit 
of sulfur soon forms in the reservoir. If the water is delivered 
to customers directly, without proper aeration, the smell of hy- 
drogen sulfid still remains in it, but the residents, at least, soon 
become accustomed to this taste, and, as otherwise the amount 
of mineral matter is not large, the water is favorably regarded. 
There is, however, a possibility in the extreme southeast that 
these deep wells may strike veins of lead and zinc, and that the 
water may be contaminated with these metals, especially the 
latter. 
(258) 
