EXPERIMENTS on tue SWEET SPRINGS. 197 
cannot fay; but from that quarter where the greateft quan- 
tity of the vapour feemed to be in motion, the found was 
plaineft; and this, during my obfervation, was the eaftern. 
The fcene lafted about half an hour, though the whole 
night was as light as when the moon is in the quarters.” 
N° XXIL 
A Letter from J. Mavison, E/7. to D. RirTennousE, 
E/q. containing Experiments and Obfervations upon what 
are commonly called the Sweet Springs. 
HESE waters rife on the north fide of a large moun- 
tain at the foot of it, called the Sweet Spring Moun- 
tain, in the county of Botetourt. The fouth fide is co- 
vered with ftones of an ocrous appearance. In many 
places iron ore may be found; but on the north the moun- 
tain is fertile, covered with a rich mould, at leaft near the 
{pring. ‘The remarkable efficacy of thefe waters in many 
diforders, efpecially, it is faid, in confumptive complaints, 
firft induced me to attempt their analyfis. Such experi- 
ments as I had time and opportunity to make, I fhall faith- 
fully relate, and leave it to others, better qualified than 
myfelf, to judge of their merits. 
Experiment 1. Having plunged a very fenfible mer- 
curial thermometer in the fpring, it ftood at 73° The 
temperature of air was about 69. 
2. A good hydrometer funk one-twentieth of an inch 
deeper in common mountain water, than in the fpring. 
3. Nut-galls mixed with the water in a wine glafs ftruck 
a palifh brown, which fhewed that there was little or no 
iron in It, 
4. Violets mixed with the water in a wine glafs, turn- 
Cec ed 
