128 PHILOSOPHICAL TRANSACTIONS. [aNNO ] 684-5, 



acids, he denies it to be dulcis, but still very corrosive, and that it is diluted 

 only as water will yet more effectually take off the pungency of the acid. To 

 the 4th, where spirit of wine preserves bodies from turning to vinegar, and 

 stum liquors, M. Kunkel says, that this is a plain proof of its being an acidum ; 

 or the sour vapour of accended brimstone produces the same effect : only with 

 this difference, that the like acidum in spirit of wine is less copious, and for 

 that reason you must use a much greater proportion of spirit. So that the in- 

 duction is false, that there is no acid in spirit of wine, since acids do generally, 

 if not always, hinder the fermenting of bodies. To the 5th he answers, that 

 spirit of wine, digested with syrup of violets, will change the colour. 



Dr. Voight having thus far been on the negative, by declaring what spirit of 

 wine is not ; he now asserts it to be an oil, which is' ardent or inflammable, by 

 no means on account of its volatile salt, for then salt of urine must burn; nor 

 on account of any acid, which has been already refuted ; much less on account 

 of its water and earth, for that would be absurd : ergo ratione olei. He gives 

 an instance how spirit of wine may be reduced to a true oil ; for as it is a spirit, 

 he says it has only lost the outward form and consistence of oil, being made 

 more fine and subtile, yet notwithstanding he proposes a way to bring it to oil 

 again : take a quantity of high spirit of wine, put it into a cucurbit, which is 

 not very well closed, let it stand for 3 months, then endeavour to rectify it in 

 a gentle balneo; you will find little spirit that will rise, but a good quantity of 

 inflammable oil will remain at the bottom. 



M. Kunkel's answer principally consists in denying the experiment, of re- 

 ducing spirit of wine to oil, by the way and method proposed, or by any other : 

 unless he perhaps first united some oil with his spirit, and then the air having 

 sublimed the spirit, which was lighter than the oil or water, by this means per- 

 haps, he obtained some little oil. 



Dr. Voight examines an epistle of M. Kunkel's, sent to him for that pur- 

 pose. The first presupposition of the author of the epistle is, that all vegetables 

 contain an acidum et urinosum. The 2d, that all fermentations produce acids, 

 which are separable by art. In answer to the first. Dr. Voight complains of his 

 having omitted oleum, which is more certain, and constant in all vegetables, 

 than acidum. For pepper, ginger, camphire, nutmeg, &c. have no acidum. 



M. Kunkel will not allow his instances in pepper, &c. to be just, but on the 

 contrary, that they contain a sal volatile et fixum, or an alcali salt. 



Dr. Voight goes to the 2d supposition of M. K. that all fermentations pro- 

 duce acids, which are separable by distillation. This he refutes, as contrary to 

 experience, since mead, and Canary wines, and even their Berlin beer itself, 

 will ferment very high, without any acidity, but rather continue very pleasant 



