108 



portant particulars bearing upon this point will be borrowed and 

 incorporated in a more detailed report. 



Among the general considerations in relation to them, which may 

 with propriety be introduced in this place, it is worthy of remark, that 

 while the thermal springs to which we have referred, in treating of 

 the Warm spring valley and other places, appear to be indebted 

 for their impregnation chiefly to rocks of a calcareous description, 

 and are accordingly found in or near such rocks, the sulphuretted 

 springs now referred to, among which are the White, Red, Salt, 

 Blue and Gray Sulphur springs, appear to derive most of their in- 

 gredients from pyritous slates, and will therefore be observed to rise 

 through or in the neighbourhood of strata of this nature. Of these, 

 the White Sulphur is the only one which can be regarded as de- 

 cidedly thermal, its temperature being about 64°, while the others 

 do not vary considerably from the usual temperature of the ordinary 

 springs around them. 



Another point of a general character which may be noticed here, 

 is the radical difference as to saline and gaseous ingredients ob- 

 servable between the springs formerly alluded to, and those of 

 which we now speak. All the waters of the Warm and Hot and 

 Sweet springs valley, and several others of analogous character, 

 and highly thermal temperature, discharge considerable quantities 

 of free gas, consisting of carbonic acid and nitrogen, of which the 

 latter was first distinctly recognised by myself, and found in general 

 to be present in very great proportion. 



At the same time a large amount of carbonic acid is held in 

 combination in these waters, imparting the acidulous character for 

 which some of them are remarked, and giving them the power as 

 already mentioned of holding large quantities of carbonate of lime 

 dissolved. This acid impregnation is in no instance more strikingly 

 manifested than in the waters of the Sweet spring valley, of which, 

 that of the Red spring about a mile below the principal fountain of 

 the Sweet springs, presents an amount of the combined gas equal 

 in volume to about one half of that of the water itself. 



Another important distinctive feature in the constitution of the 

 class of springs here spoken of, is the large amount of the carbo- 

 nates, principally that of lime, and the comparatively small proportion 

 of the sulpJiatcs with which they are impregnated. 



On the other hand, the class of sulphuretted waters as exemplified 



