Account of the Yellow- Springs. 209 



mental chemist, his judgment will easily decide on their 

 qualities. 



It thus becomes highly interesting and necessary for 

 those who have any chemical knowledge, and visit these 

 springs, to examine their contents, and, by describing 

 their most obvious qualities, lead the way for future in- 

 vestigation. With these intentions, I have undertaken 

 the following experiments on the Yellow- Springs, in 

 Pennsylvania, from which if I have drawn conclusions 

 different from the general opinion, I beg at least that they 

 may be treated with candour, till it has been ascertained, 

 by others, that they are unfounded. Having, however, no 

 favourite theory to support, and being perfectly uninflu- 

 enced by prejudice or self-interest, it may be expected 

 that my inquiry should be conducted on the principles 

 of an impartial judge, rather than a popular advocate. 



The situation of the country in the neighbourhood of 

 the Yellow- Springs is highly picturesque. The grounds 

 are elevated, and healthy. The Springs are situated in 

 a valley, surrounded by hills, which are chiefly compos- 

 ed of granite, in a great variety of combinations, binary, 

 ternary, and quaternary ; but the principal combinations 

 are felt- spar and quartz, occasionally interspersed with 

 mica, and sometimes with small particles of fibrous 

 schorl. 



In the hills to the north-east of the Spring, are found 

 large masses of trap, sometimes of a columnal form, ge- 

 nerally quadrangular, internally of a greyish black colour, 

 and externally covered with a brown crust, or oxyd, evi- 



