of the Yellowstone and Firehole Rivers. 109 
declivity, over which the water flows with this brilliant coat- 
ere are also a number of chimneys, with walls from 
four to ten feet in height. Some of them are nearly circular at 
base, with an aperture at top of a foot or more, lined inside with 
a coating of carbonate of lime, which is hard, smooth and like 
porcelain in luster. The oblong mounds vary from a few feet 
to one hundred yards in length, ten to twenty feet in height, and 
fifteen to twenty feet around the base. These generally have a 
fissure along the summit, in some of which the waters can be 
heard seething and boiling like a cauldron. These fissures all 
have the same beautiful white porcelain lining, and in some of 
them the brilliancy is greatly intensified by the precipitation of 
vivid yellow sulphur in acicular crystals, but so delicate that 
they disappear at the touch. On the east side much of this 
deposit has been reduced to a fine powder, so that the surface 
is as white as snow. A qualitative analysis made at the springs, 
shows that the water contains sulphuretted hydrogen, lime, soda, 
alumina, and a slight amount of magnesia. Carbonate of lime 
predominates over all other elements in the deposits, and they 
rai 4 be divided again into intermittent, boiling and spouting, 
and quiet springs. Those of the first class are always above 
boiling point during the period of action, but during the inter- 
val the temperature lowers to 150°. Those of the second are 
always at the boiling point, and some of them throw the water 
up two to six feet, by regular pulsations. The springs of the 
third class may have once been geysers, but are now quiet, and 
have a wide range of temperature, from 188° to 80°. ‘Where 
the temperature is reduced below 150°, great quantities of the 
our present peri e center of activity may have whaeral 
and statood ts its 
