J30 PHILOSOPHICAL TRANSACTIONS. [aNNO 1 684-5. 



efFervescence in their mixture, as sal tartari, et spiritus vitrioli do. He de- 

 mands an experiment how to make an acidum ex sale alkali. 



M. Kunkel answers, that while these salts are in their gross form, as he 

 stiles it, they are very different: but, in a book he calls his Annotations, he 

 shows a way how to reduce alkalia to acida, et vice versa : and that only by de- 

 priving one of its terrestreity, and giving it to the other. He instances in sal 

 absinthii, out of which a spirit may be drawn to dissolve gold. 



Dr. V. animadverts farther on the epistle, where he finds this assertion ; " no- 

 body can deny, where you have heat and light, you must needs have two con- 

 traries, viz. heat and cold, or an acidum and a urinosum." This the animad- 

 verter says, is contra rationem : for two contraries, non possunt immediate 

 eundem efFectum producere. He says acidum et urinosum may perhaps be ex- 

 ternal or accidental causes of heat, by promoting a sudden motion and conflict 

 in some bodies, but must not be confounded with the matter that is inflammable. 

 Thus, water and oil of vitriol mixed together, produce a much greater heat 

 than if there be put into the oil of vitriol a quantity of urinous salt : but it is 

 plain, that in the water there is an urinosum. Thus if you pour water upon 

 calx viva (which is an alkali, and has nothing to do with acidity,) you will pro- 

 duce a great heat ; yet we want here one of the two principles of heat, viz. the 

 acidum. M. Kunkel thinks he has made it clear, that these two principles 

 were demonstrated very plainly : to elucidate the matter, he gives some effects 

 of sp. acidi (as for instance aquafortis,) and urinosi (as sp. urinae itself;) these 2 

 ■ in conjunction dissolve gold, make aurum fulminans, produce heat, flame, and 

 even lightning. As to the experiment of water and oil of vitriol, he answers, 

 that though he should still continue to deny, that water holds no urinosum, 

 yet he must allow it to be a frigidum, which yet afforded this warming effect. 

 As to the experiment of calx viva, he will not allow it to be without an acidum. 

 He would confirm his opinion by an instance of the great phosphorus, called in 

 England the solid, which he says has nothing either oleaginous or resinous, but 

 holds salia acida et urinosa, and yet performs so many luminous effects. 



Dr. Voight observes, that the author gives the reason why sp. of nitre and 

 sp. of wine make so great an ebullition, but sp. of wine and oil of vitriol none 

 at all : viz. because nitre is not so pure an acid as vitriol ; for which reason they 

 may stand the quieter, and without alteration together. To this reason the 

 doctor gives no credit, for he says, sp. of nitre is as pure as that of vitriol, and 

 that with sp. of wine, they make an alteration : and the higher they are, the 

 more they heat ; but if very highly rectified, they will produce flame on 

 mixture. 



M. Kunkel seems to be in nowise of his judgment, that the mentioned acid 



