UNDERGROUND TEMPERATURE, 
II 
generated j either by the constituents contained in the water^ or 
transmitted by the chemical decomposition of the environing strata, 
because of the high temperature to which the water sometimes 
attains, and its continuance for such long periods as are known. 
Salt and mineral waters have a slightly higher temperature than 
fresh, but from the experiments of Dr. Gustav BischoP it would 
appear that the addition of such salts as these waters contain, causes 
a very slight increase in temperature. He says : The Heilbronn, a 
mineral spring in a small valley of the Brohl, four miles distant from 
the Lake of Laach, is next to Biliii, near Bohemia, the richest in 
carbonate of soda known to me. It contains 0*0053 of fixed 
substances. Suppose that this spring were formed from anhydrous 
carbonate of soda, bv the addition of concentrated sulphuric and 
muriatic acids ana water, tnen according to my analysis 77*4 parts 
anhydrous carbonate of soda, 5 parts of concentrated sulphuric 
acid, 92 of smoking muriatic acid, and 22*687 parts of water 
would be required to compose a water containing the same pro- 
portions of carbonate and sulphate of soda and of chloride of 
sodium as that spring. In accordance with this, therefore, I put 
7 7 '4 grains of calcined carbonate of soda to 22*687 grains of water. 
The temperature of the water was— - 
Before the experiment - - - 42°* 8 
After - - - - - 43^7 
Increase of Temp. 0*9 
To this solution of soda I added a mixture of 5 grains of 
concentrated sulphuric acid, and 92 grains of smoking muriatic 
acid. The temperature of the two liquids was — 
Before the mixture . - - - 50° 'oo 
After ----- 5 o°-45 
Increase of Temp. - o'45 
1 Physical, Chemical| and Geological Researches on the Internal Heat of 
the Globe, p. 16. 
