Gray Sulphur Springs of Virginia. 107 



ted, attended by the production of nitrous acid fumes. The clear 

 solution on being decanted, gave a copious precipitate with chloride 

 of barium, thereby evincing the presence of sulphur. 



b. For Fluorine. — A portion of the precipitate was introduced 

 into a platina crucible and treated with sulphuric acid as in J without 

 obtaining any evidence of this principle. 



c. For Iron. — Water was added to the residuum in b and the so- 

 lution tested with tincture of nutgalls, and also with the ferrocyanide 

 of potassium ; with the former it instantly struck a dark ink and with 

 the latter, a blue precipitate. Iron therefore, is an ingredient of the 

 precipitate. 



d. For Silicic Acid. — There remained behind after the addition 

 of water in a and c, a copious siliceous deposit. 



e. For Manganese. — A portion of the precipitate from the vial 

 was treated with borax before the blowpipe, but only yielded a glass 

 stained with iron. Therefore, no manganese is present. 



The water through which the precipitate was diffused in the vial, 

 was filtered and evaporated in a porcelain capsule. It emitted a 

 distinct odor of extractive matter, and soon gave rise to a pellicle on 

 its surface. The evaporation having been pushed nearly to dryness, 

 it was suffered to cool, when it shot into minute crystals of sulphate 

 of lime, intermingled with those of sulphate of soda ; the former pre- 

 ponderating in quantity, and when viewed with a microscope seem to 

 be in slender prisms, crossing each other at 60 and 120°, and formino- 

 six-rayed stars. 



The striking difference in the results of evaporation between the 

 water from the other bottles, and that in the present case can in no 

 other way be accounted for, than by attributing it to the oxygeniza- 

 tion of the sulphur by the atmospheric air in the upper part of the 

 vial ; whereby sulphuric acid was formed, which decomposed the car- 

 bonates of lime and soda. 



The foregoing experiments prove that these springs contain the 

 followino; ingredients : viz. 



It next becomes a subject of inquiry in what manner these differ- 

 ent principles are combined among themselves. 



