1 24 Analysis of the Pittsburgh Mineral Spring. 



the needle. It was also satisfactorily settled by the experi- 

 ment of Mr. Barlow and others, that this plane cuts the ho- 

 rizon in a line due east and west, and to which it inclines 

 at an angle, which in all parts of the earth, is the comple- 

 ment of the dip. Now supposing Mr. Barnes' experiments 

 to have been conducted with perfect accuracy, and allowing, 

 what is very questionable, that they are susceptible of per- 

 fect accuracy — he has only ascertained a fact which any 

 person might have learned by a bare inspection of the dip- 

 ping needle. For as has been remarked, this line of no at- 

 traction, or the " neutral point" as it is denominated in the 

 " Notice," is in all cases the complement of the dip. 

 Whether Mr. Barnes is correct in stating the dip at New 

 York to be 67| degress, (which is the complement of 22i,) 

 observers in that city, will either confirm or correct. 



It is not intended by any thing that has been said to un- 

 derate in the slightest degree, the importance of experi- 

 ment, for I am well aware that a single new fact thus ascer- 

 tained, is of more importance to the cause of science, than a 

 score of crude speculations. Yet it is difficult to determine 

 how much credit will be awarded to an experimenter who 

 announces a result as "curious and interesting," without a 

 knowledge of what has previously been done by others. 



A Surveyor. 



Art. XIX. — A Chemical Analysis of the Pittsburgh Mineral 

 Spring; by William Meade, M. D. 



TO THE EDITOR. 



Sir — A mineral spring having been lately discovered on 

 the estate of J. S. Scully, Esq. near Pittsburgh, in the state 

 of Pennsylvania, which had attracted considerable attention, 

 I was favored by the proprietor with a few bottles of the 

 water carefully put up, with a request that I would make 

 a Chemical Analysis of it, with some observations on its medi- 

 cinal qualities. The result of this analysis, I now take 

 the liberty of sending to you, together with some extracts 

 from the remarks which I have made on the general proper- 

 ties of a class of mineral waters, which are ranked as chaly- 

 beates, and which are not uncommon in this country, though 

 not generally known, or their valuable properties fully appreci- 



