132 PHILOSOPHICAL TRANSACTIONS. [aNNO 1684-5. 



far overbalanced by the acidum, that we can discern no frigidum at all. In this 

 menstruum all metals can be dissolved, excepting gold, which requires a frigidum 

 to be joined with a calidum. 



These terms of acidum, urinosum, and alkali, have so much confounded all 

 men, that it has moved him to write particularly and copiously of them, in labo- 

 ratorio suo experimentali. But in short, he finds all acids, excepting oleum 

 vitrioli, to consist of salia composita, mixed with sal frigidum. Alkali salts are 

 all much the same, if clean and pure, and nothing else but salia acida cum fri- 

 gidis, and are much akin to common sea salt, when that is dispirited. The 

 acids, if fixed by a mixture of earth, become alkali salts. But by joining pure 

 oil of vitriol with such an earth as cornu cervi calcinatum, which carries in it 

 no more of an acidum, or of an urinosum, this will not yet agree with other 

 alkalies, unless by giving it a supply of an urinosum. 



Salia frigida, if pure, are all homogeneous, of whatever vegetables or animals 

 they may be made; from whence he infers, that nature only makes use of these 

 two principal parts, which, since he came to understand it, has excused him 

 from many a troublesome work or operation, and would also much lessen the 

 processes of many, and lighten their labours, did they but know the true pro- 

 perty of those bodies they work upon. 



Since now he supposes himself to have laid this firm foundation, he will only 

 hint at two or three well known materials, out of which heat and lightning 

 may be brought, in which no oleum can be demonstrated to have been contained. 

 This he needed not to have done, but with regard to the Oleisti, who would 

 fain introduce some new thing, even against experience, and who would yet 

 farther confound the confused world, through their opinionated philosophical ar- 

 guments; whereas they had more need be led out of mistakes. He begins with 

 aurum fulminans ; to prepare this is so well known that it need not be described. 

 The gold cannot be dissolved without a frigidum; but when it is once dissolved 

 by it it must be precipitated by the same again, e. g. with spirit of urine ; by 

 this means you get a powder that gives a great report, a very clear light, and 

 burns. If you cannot see the lightning, for it is very transient, put out the 

 candle, and you will easily discern it. Here is nothing but an acidum and uri- 

 nosum joined by an earth; from whence this thundering noise proceeds, of 

 which, in some manuscripts that he has yet by him, he has more copiously treated. 

 Perhaps it may be said, that if the matter were precipitated with salt of tartar, 

 it would be one and the same thing, why does this make it heat as well, as if it 

 were precipitated with an urinosum or frigidum ? he answers in few words, that 

 there is already in the solution as much of the urinosum as is necessary, so that ' 

 a farther affusion of an urinosum will not well agree. Therefore it happens. 



