118 THE MOUNTAIN. 



of these classes ; there being cold and thermal waters hold- 

 ing all of the above chemical elements in solution. The 

 mineral and gaseous contents of these waters are often in 

 great quantities and in almost every conceivable proportion. 

 Some of them have attained world-wide reputations in the 

 modification, alleviation, and cure of different classes of dis- 

 eases. Many of them are peculiar and rare in the combina- 

 tion of their mineral contents ; whilst some of the thermal 

 waters of the southern, interior, and western side of the con- 

 tinent have scarcely a parallel for intensity of heat, in any 

 other part of the world. The attempt to perpetrate any- 

 thing like an elaborate treatise on mineral waters would of 

 course be out of place here, but a hurried enumeration or 

 catalogue of the most important mineral waters of Pennsyl- 

 vania, and of the continent as far as analyzed by science and 

 registered, may not be deemed so. 



The highest knobs of the Alleghany being composed of 

 hard silicious and argillaceous masses, the materials of which 

 are only slightly soluble at low temperatures, the waters 

 which emerge from them are nearly in the same condition in 

 which they fell from the clouds. Many of this class of springs 

 are almost perfectly pure water with all the characters of 

 rain-water, and a near approach to absolute or chemical 

 water. This is the character of the higher or summit 

 springs. The other members of the rock-group forming 

 the mountain, have each their class of characteristic springs. 

 Throughout the coal series we are presented with a variety 

 of mineral elements in the waters. Common salt or the 

 chloride of sodium abounds in great quantities in some of the 

 rocks. Where they are depressed in the synclinal troughs 

 further in the coal measures, salt is manufactured from them 

 by perforating the masses containing it. Where they crop 

 out, the rocks sometimes show the presence of salt by efflo- 

 resence and sloughing on their surfaces. These formations 

 also contain bromine and iodine, or the elements of sea-water, 

 the water used at the salt-wells showing their presence in 

 considerable proportions. 



