ORIGIN AND USE OF NATURAL GAS AT MANITOU. 27 



springs are found. Heated waters, or waters even slightly 

 heated, on coming into contact with the superincumbent lime- 

 stones of Alanitou would promptly set up chemical reactions 

 caused by the presence of soluble matters such as the silicates 

 of the alkalies and other metals, silicic acid, sulphides, sul- 

 phates, etc., derived from the heated rocks. The reactions 

 which would take place need only be generally indicated here 

 since they are not peculiar to this theory. Alkaline silicates 

 would change to carbonates; alkaline bicarbonates, in so far 

 as these reactions were possible, to sulphates, or, — if chlorine 

 combinations of lime and magnesia exist in the silurian lime- 

 stone — to chlorides, in both cases — at even a very moderately 

 elevated temperature — with the evolution of carbon dioxide; 

 iron salts would first become carbonates and then peroxidize, 

 setting carbon dioxide free and forming a ferruginous pre- 

 cipitate. If the waters were only slightly hot, silicic acid 

 would form insoluble calcium silicate with the liberation of 

 carbon dioxide. In the case of hot waters the basic carbonates 

 of magnesia and probably also of calcium would be formed 

 instead of normal or acid salts by reactions of the salts of 

 the alkalies, etc. These, with other known and possible re- 

 actions, account for the generation of the gas. The salts con- 

 tained in the spring waters may also be fairly explained in 

 part by these reactions, and in part by reactions produced, 

 and other salts introduced, through the accession of seepage 

 waters in the passage to the springs. The concentration of 

 solutions, or the high percentage of salts in the water, is well 

 explained by this derivation. A large fissure like the one 

 assumed to exist at Manitou must receive meteoric waters by 

 seepage along its whole course, and such additions bring with 

 them each their small quantity of dissolved salts. The waters 

 which emerge from the fissure at or above Manitou must 

 also be considerably changed in mineral contents by the 

 accession of seepage waters from the local rocks, and these 

 changes are probably greater at some points than at others. 

 The difference in temperature between the various springs, 

 and also their difference in mineral matters dissolved in the 

 water, may thus be credibly explained. The surface waters 

 do not readily make their way through the "soda-rock"' into 



