Sea. 1 6.

Of Salts.

317

• 64.1. Petroleum, Oil of Pe-ter. This is a Mineral thrown up,and diftill'd as it were by a fubterra-nean Heat, in fevera! Mountains inItaly and Naples; from whence itdrains down, and lies upon the Sur-face of Lakes and Fountains, onfome of which, Naturalifts report,it continues burning, and particular-ly near the antient City of Babylon,and alfo at Mejanum, a Village inthe Parmefan. It is much com-mended in many outward Com-plaints, as Rheumatic and Arthri-tic Pains, and Paralytic Limbs;becaufe it is very warm and pene-trating. Some Perfons with thefeMineral Oils have lately fet up forEmpirics in the Gout; but eventheft, as well as all other Medicines,will not anfwer the Pretenfions offuch as know not how to ufe them.We have Directions to rectify thisOil in Schroder, and fome others ;and to make fome other Prepara-tions of it ; but they can be of nofervice to the Reader, becaufe theyare neither prefcribed nor made byany in the prefent Practice.

642. Oleum Tire«, Mine-ral-Oil. This ieems to be only ageneral Name for the foregoing, andto fignify nothing particularly.

643. Bi smut hum, Bifmuth.This is a fulphurous Marcafite, orRecrement of a Metal, being fomemineral Mfcer impregnated withTin ; and therefore 'tis call'd Tin-Glafs. But what we have from theT>ruggifls now, is factitious, andcompos'd of Ttn, Tartar, and Ar-fenic, made in the northern Partsof Germany, from whence it isbrought to England. It is fmooth,white, brittle, and breaks in largeFlake?) like Regulas Martis.

'Flores Bifinuthi, Iltvers of

Bifmuth.• Beat the Bifmutb into very fine' Pouder, and to j iv. of it, put

* ft fs. of Nitre alfo in fine Pou-' der : put in that Mixture by half a' Spoonful at a time into an earthen

• Body perforated in the fide; when' the Body is red-hot, and the Ope-' ration is over, take away the A-' ludels, and wipe off the Flowers' with a Feather.'

Thefe are very white, and ufed atan excellent Fucus, mix'd with Po-matum, or B.ofe-Water : but theymuft not be too bufy with it, whotry it upon their Complexions > forthe faline Parts of the Arfenic maydo mifchief many ways. But if theNitre and the Arfenic Salts arewafh'd away by frequent Solutionsin warm Water, it will not onlycontinue to be a good Cofmetick,but alfo may with fafety be giveninternally, and by fome is reckon'da good Diaphoretic. Yet as the Ma-teria, Medica is large enough in itsSupply for that Intention, there isno occafion to torture a Poifon tomake a Medicine of it. Its Dofeand Virtue, in the manner directed,is the iàme as of the Be x,oar Mineral.

Magiflery of Bifmutb.' Put Spirit of Nitre ft i. (made■ with Oil of Vitriol) into a great« Body uncut, and add to it as much' Pouder of Tin Gla/s, or Bifmutb,' by 5 i. at a time, as the Spirit is' capable of diffolving; which will' be about 3 vii. or 5 viii. Then' take two Gallons of Water, and' diifolve in it 5 iv. of common' Salt: filter the whole, and put it' into a clean earthen Pan. Pour' upon it the Diffolution of Bifmutb,' and immediately it will turn milky,' and a Precipitate will fall. Per-« mit