220 Dr. Marcet on an Aluminous Chalybeate Spring 



2, The experiments D and E concurred to show that the water 

 did not contain any sensible quantity of carbonats. 



4. The experiments F and G afforded additional evidence of 

 the presence of iron, and whilst they shewed the existence of lime 

 in the water, seemed to indicate that the quantity of this earth was 

 not considerable, 



5. It appeared probable from experiment K, that the water con- 

 tained a small quantity of muriatic acid. 



6. The change produced in experiment B, on the infusion of 

 Brazil-wood, appeared at first ambiguous ; it could not be owing to 

 the prevalence of an alkali or carbonated earth, since the water 

 turned litmus red, and since the presence of carbonated earths had 

 been disproved by other results. But having found by comparative 

 trials, that solutions of sulphat of iron changed paper stained with 

 infusions of Brazil-wood to a black, or at least intensely dark violet 

 colour, and that solutions of alum turned it crimson ; and observing 

 that a mixture of these solutions produced a dark purple hue, the 

 appearance in question was easily explained. 



7. The result of experiment L indicated the presence of sul- 

 phuric acid. 



8. Upon the whole, and from a review of the foregoing expe- 

 riments, the substances which, at this early stage of the analysis, the 

 water appeared most likely to contain, were sulphat of iron^ sulphat 

 of alum'ine^ sulphat of lime, and a small quantity of muriatic salts. 

 Some sulphat of magnesia, and some alkaline sulphats, might possibly 

 be contained in the water, though their presence could not be satis- 

 factorily ascertained by these preliminary experiments. 



