132 Analysis of the Pittsburgh Mineral Spring. 



serving its powerful medicinal qualities as a chalybeate, bu£ 

 for an accurate and able analysis of it, I must refer to an es- 

 say of Professor M'Neven, of New York, where it will be 

 foundfthat the whole contents of one gallon of the water are 

 only about eight grains ; two grains of which consist of ox- 

 ide of iron — and that one quart contains nineteen cubic in- 

 ches of carbonic acid gas. Here then we have a mineral 

 water of acknowledged reputation which does not contain 

 much more than one fourth the quantity either of iron or sa- 

 line solid contents, which we find in the Pittsburgh spring, 

 and as nearly as possible the same quantity of carbonic acid 

 gas. I could refer to many other springs of the same nature, 

 in this country, possessing the same properties, but scarcely 

 one have I ever examined, possessing them in the same de- 

 gree ; among others, the Yellow Springs, in Pennsylvania, 

 where beautiful buildings are erected, and accommodations 

 of every kind are prepared for the invalid ; yet, having myself 

 made an analysis of this water with great care, I found that 

 it had no claim to rank as a chalybeate of a superior order. 

 In fact, all those mineral springs which are impregnated with 

 iron, held in solution by the carbonic acid gas, in whatever 

 country they are situated, are properly called chalybeates, 

 and are endowed with nearly the same medicinal properties. 

 What these are I shall now proceed to point out. 



SECTION VI. 



On the medicinal qualities of the waters of the Pittsburgh 

 Mineral Spring, with observations on the effect of such 

 waters on the system. 



The operation of the chalybeate waters, perhaps the most 

 important class of natural medicines, has greatly occupied 

 the attention of practical physicians. Much refinement has 

 been introduced into the subject, which it is my intention to 

 avoid, as my main object is to point out the principal ef- 

 fects which such waters produce on the system, and the dis- 

 eases to which they are more particularly applicable. Let 

 me however premise, that though the principal virtues in 

 those waters are derived from their chalybeate impregnation, 

 yet certain differences will arise, which modify or alter their 

 operation. These may be traced either to the presence of 

 an active neutral salt or to a large excess of carbonic acid. 



