VOL. IX.] PHILOSOPHICAL TRANSACTIONS. ISQ 



taken out of the omasus of ruminating animals, without any further digestion 

 or preparation, yield a volatile salt, when fermented or putrified in the open air, 

 without additament. 



3. Most vegetables, whether woods or herbs, if burnt whilst they are green, 

 and with a smothering fire, yield salts which are far enough from alcalisate; 

 being either neutral or acid, or to speak more properly, tartareous; for they 

 almost exactly resemble purified tartar; and by distillation yield the very same 

 substances. Indeed some few herbs, such as satureja, rosemary, &c. which 

 abound with a sprightly volatile oil, if they are well dried, on simple incineration 

 yield an alcalisate salt ; so do some dry woods. But that they are produced by 

 the fire and not separated, I shall prove from experiments which I think un- 

 questionable. 



4. In the most natural method of analysing plants, which is by fermentation 

 or putrifaction without additaments, or the intervening of a suspicious analyser, 

 we receive oil, acid spirit, and volatile salt copiously ; all which did evidently 

 pre-exist. But if the herbs are perfectly or entirely putrified, little or no alcali 

 can be extracted from them ; as neither from rotten nor putrified wood ; the 

 active salts, by whose combination the alcali is produced, being either expired or 

 evaporated. 



Next I am to inquire, how the fire produces this alcali : whether by the 

 changing of one single pre-existing principle ; or by enabling any among them 

 to make so notable an alteration on or in the other; or lastly, whether it is 

 effected by the union of two or more active principles, which thereby become 

 different from what they were before the said combination ? 



I shall not at present trouble you with the reasons, experiments, and observa- 

 tions, which have induced me to reject the former ; but briefly suggest those 

 which encourage and dispose me to believe and assent to the latter : so that this 

 is my position : that alcali salts do result from the combination or union of the 

 saline and sulphureous principle. But whether it is the volatile or acid salt, 

 which combines with the oil or sulphur, is now the subject of our inquiry. The 

 ensuing considerations seem to determine in favour of the acids. 



First, tartar, which is sensibly acid, and from which volatile salt cannot be 

 separated by any commonly known method, by bare calcination, becomes a 

 strong and perfect alcali. Secondly, nitre, an undoubted acid, with a small pro- 

 portion of mineral or vegetable sulphur, is converted into a genuine fiery alcali. 

 Thirdly, nitre which is made by the affusion of an acid spirit on an alcali, may be 

 almost totally distilled into an acid spirit, there appearing not the least traces of 

 a volatile salt, and scarcely any of the alcali, out of which it was chiefly pro- 

 duced. 



