MEDICAL PAPERS. 



372 



I have fmce had opportunities of profecutuig that fub- 

 jed farther, by a number of additional experiments, which, 

 together with the hiftories of feveral cafes, that have oc- 

 curred in my attendance here, will more clearly afcertain 

 the contents of thefe waters, and determine the effects 

 which may be expedled from their ufe, in the cure of 

 difeafes. 



I therefore take the liberty to tranfmit you the follow- 

 ing account, which I flatter mylelf, will be favourably re- 

 ceived as an ufeful lupplement to my former letter. 



The experiments! related to you in my laft, tended chief- 

 ly to fliew that thefe waters owed their chief impregna- 

 tion to Iron kept in folutlon, by means of an acid, which I 

 judged to be of the vitriolic kind. 



Thofe which I am now to communicate to you confirm 

 this opinion, and at the fame time difcover fome other 

 principles, in their compofition, with which I was before 

 unacquainted, and which probably increafe their medical 

 virtues. 



Experiment I. Upon the addition of Sp. Sal. Arom, to 

 the water a flight effervefcence enfued, and uponftanding 

 about an hour, alight yellow matter was feperated and 

 floated on the top of the liquor. 



II. From a mixture of lime water, the fame feparation 

 was made, but fell to the bottom of the liquor. 



III. PowderM chalk added to the water produced the 



fame feparation, but not in fo fliort a time, as in the pre- 

 ceding experiments. 



IV. Therefiduum, after a flight calcination, was flrongly 

 attradcd by the magnet. 



V. A folution of crudeSal. Ammon. being mixed witb 

 the water, was fucceeded by the fame appearance as the 

 addition of lime-water. 



VI. The refiduum after evaporation in Bain. Mar. be- 

 fore calcination, difcovered to the tafl:e a confiderable por- 

 tion of fait, which left a coldncfs on the tongue, and when: 

 feparated by folution, filtration and evaporation, appearecf 



of 



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