J4 2 Of Salts. Par 
T 
they make Beds fometimes an hundred feet long , and 
fifteen broad at top ; well rarnd 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 diffoiv d • 
and in five or fix years time, begin to turn into a kind of 
Vitriolick Earth, which will fwell and ferment like levened- 
Dough. And once in four years, the Bed is renewed with 
frefh Stones. In a Boyler containing about twelve Tuns of 
VitriolicJ^ Liquor running from the Bed, they put in by 
degrees, about fifteen hundred pounds of old Iron 5 which 
both quickens the boy ling, and prevents the fetlmg and 
melting of the Copperas at the bottom of the Boyler, and 
of the Boyler it felf. Sometimes, in furring the Earth on 
the Beds, they find pieces of Native Copperas. See a parti- 
cular and exacl: account of thefe Works at Debt ford, com- 
municated by Mr. Colwal, the Founder of this Mufctiwi, 
(a) N, 142. anc i b y Me publilhed in the Philofophical Tranf aft ions, (a) 
Of the Nature of Vitriol, fee feveral confiderable Obferva- 
(b) N. 103. ^ns grounded on Experiment, in the fame Trajifaftions. (b) 
Amongft other particulars, an excellent way of purifying 
it from its Okre. 
The three principal Parts hereof are, an Acid Spirit^ fixed 
Salt,and Sulphur. The laft,a good Hypnotick^, in feme Cafes, 
where Opium is not fafe. 
(e) Aidrov. Native Vitriol, faith Ambrofinus, (c) given to the quan- 
MutMct. t j t y Q f 3j m an y C011ven j ent vehicle, is a great Remedy in 
Germany and Hungary for the Plague. Blew Vitriol of ex- 
cellent ufe againft Venereal V leers. Both of this, and the 
Green, is made the Powder called Sympathetic/^ theDe- 
fcription whereof may be feen in Papinius, and out of him 
in Wormius. I doubt not, but that the Stiptic/^ Liquors of 
Mr. Lyfter and of Mr. Deny, are both made of Vitriol. 
A fort of ALUMINOUS Earth, -found near the River 
Patomach in Virginia. 'Tis foft and very light 5 of an afti- 
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 
(^)^ t s .°3-the Philosophical Tranfaftwns. (d) Of the Englijh Alum- 
nu'd,N.jo4. Works an accurate Account, communicated by Daniel Col- 
it) Num. wa i £fq. anc j by jyie publiihed in the fame Transactions, (e) 
h*> The 
