Of Salts-. 
Part HI 
34 2 
they make Beds fometimes an hundred feet long, and 
fifteen broad at top ; well ram’d firft with Clay , and then 
with Chalk. In thefe Beds the faid Stones are laid about two 
feet thick: which by Sun and Rain, are gradually diffolv’d ; 
and in five or fix years time, begin to turn into a kind of 
Vitriolic/^ Earth , which will fwell and ferment like levened- 
Dough. And once in four years, the Bed is renewed with 
frefli Stones. In a Boyler containing about twelve Tuns of 
Vitriolic 4 Liquor running trom the Bed, they put in by 
degrees, about fifteen hundred pounds of old Iron ; which 
both quickens the boyling, and prevents the fetling and 
melting of the Copperas at the bottom of the Boyler, and 
of the Boyler it fell. Sometimes, in ftirring the Earth on 
the Beds, they find pieces of Native Copperas. See a parti¬ 
cular and exact account of thefe Works at Debt ford, com¬ 
municated by Mr. Color al, the Founder of this Mufieum, 
00 N. 142. anc j ky jyj; e published in the Philofophical Tranfaffions. (a) 
Of the Nature of Vitriol , fee feveral confiderable Obferva- 
OON. 103. tlons grounded on Experiment, in the fame Tranfatlions. (b) 
Amongft other particulars, an excellent way of purifying 
it from itsOkre. 
The three principal Parts hereof are, an Acid Spirit, fixed 
Salt, and Sulphur. The laft,a good Hypnotic 4 , in fome Cafes, 
w'here Opium is not fafe. 
M Aldrov. Native Vitriol , faith Ambrofinus , (c) given to thequan- 
Muf. Met. t j t y 0 p 5j j n an y convenient vehicle, is a great Remedy in 
Germany and Hungary for the Plague. Blew Vitriol of ex¬ 
cellent ufe againft Venereal Vlcers. Both of this, and the 
Green, is made the Powder called Sympathetic 4 ; theDe- 
feription whereof may befeen in Papinius, and out of him 
in Wormius. I doubt not, but that the Stiptick. Liquors of 
Mr. Lyfter and of Air. Deny, are both made of Vitriol. 
A fort of ALUMINOUS Earth, found near the River 
Patomach in Virginia. ’Tisfoft and very light 5 of an afli- 
colour, and acid-aftringent Taft, almoft like that of Alum. 
Whether the people there make Alum of it, or ufe it in 
Deying, we have no account. 
Of the Nature of Alum, fee a very good Difcourfe in 
and conti° 3 ' *he Philofophical Transactions, (d) Of the Englijh Alum- 
nu’d.N. 104. Works an accurate Account, communicated by Daniel Col- 
(e) Num. xral Efq; and by Me publifhed in the fame 7 ran factions, (e) 
