342 Of Salts. Part III. 
they make Beds fometimes an hundred feet long , and 
fifteen broad at top 5 well rarn 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 diifolv'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 
frefh Stones. In a Boyler containing about twelve Tuns of 
Vitriolic^ Liquor running from the Bed, they put in by 
degrees, about fifteen hundred pounds of old Iron 5 which 
both quickens the boyling, and prevents the feeling 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, thev find pieces of Native Copperas. See a parti- 
cular and exadt account of thefe Works at Debt ford, com- 
municated by Mr. Colwal, the Founder of this Mufdeum, 
(a) N.142. an j by Me p U blifhed in the Philosophical Traiifattions. (a) 
Of the Nature of Vitriol, fee feveral confiderable Obferva- 
CW. 103. tl0ns grounded on Experiment, in the fame Tranf actions, (b) 
Amongft other particulars, an excellent way of purifying 
it from itsOkre. 
The three principal Parts hereof are, an Acid Spirit y fixed 
Salt, and Sulphur. The laft,a good Hypnotic!^, in fome Cafes, 
where Opium is not fafe. 
(c) Aidvov. Native Vitriol, faith Ambrofinus, (c) given to the quan- 
Muf. Met. t j t y Q f 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 V leers. Both of this, and the 
Green, is made the Powder called Sympathetic^ theDe- 
fcription whereof may be feen in Papinim, and out of him 
in Wormius. I doubt not, but that the Stipticl^ Liquors of 
Mr. Lyfter and of Mr. Deny, are both made of Vitriol. 
A fort of ALUMINOUS Earth, found near the River 
Tatomach in Virginia. Tis foft and very light 5 of an a tri- 
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. 
Or the Nature of Alum, fee a very good Difcourfe in 
CjJ) the Philosophical Tranf anions, (d) Of the Englijh Alum- 
nu'd^o4. Works an accurate Account, communicated by Daniel Col- 
CO Num. m l £fq. and by Me publifhed in the fame Tranfaclions. (e) 
H*. * r The 
