TOL. IX.] PHILOSOPHICAL TRANSACTIONS. l6j 



operation of the sulphur on the acid salt, supposing it such, there is a comminu- 

 tion of its parts, and thereby that made a volatile salt which was before acid, 

 only magnitude discriminating between them: and that they are often thus pro- 

 duced by each other, I could fully and at large evince. 



Having dispatched this, I cannot but take notice, that I am credibly inform- 

 ed, that many persons, of no ordinary repute for their skill in chemistry, and 

 other arts subservient to experimental philosophy, have been pleased to censure, 

 in an unusual measure of severity, an assertion, accidentally dropped from my 

 pen, in a discourse concerning the volatile salts of vegetables, in N° 101 of the 

 Philos. Trans. ; which, although circumscribed by a parenthesis, and an alien to 

 the main design and scope of my undertaking, yet was so far from being there- 

 by protected, that it has sustained the brunt of many unkind reproaches, and 

 been represented as a position without foundation in reason or experience. I 

 shall not endeavour, by an elaborate apology, to vindicate myself from that dis- 

 grace, whereunto a charge of being inconsiderate, injudicious, or (which is still 

 worse) insincere, must necessarily expose me; but shall nakedly and simply re- 

 hearse, without flourishes, digressions or circumlocution, the reasons, obser- 

 vations, and experiments, which induced me to embrace and publish an opinion, 

 so contrary to what has been hitherto generally received : and I shall then ap- 

 peal unto all unprejudiced, impartial, and intelligent persons, whether the ar- 

 raigned position be ungrounded and temerarious ; or rather, whether the argu- 

 ments I have produced in its favour, and for its confirmation, do not render it 

 highly probable, and excuse any, who shall give it entertainment^ from sus- 

 picion of levity or too prompt credulity. 



My assertion was, that alcalisate or fixed salts, extracted out of the ashes of 

 vegetables, do not differ from each other; as neither do their vinous spirits; yet 

 with this restriction, if they were highly rectified or purified. And that I may- 

 further manifest, I do not distrust my cause, I shall add, nor volatile salts, not 

 only of vegetables, which I did heretofore faintly affirm, but even those yielded 

 by animals or minerals, with the before-mentioned limitatidn of due puri- 

 fication. 



First then, I say, that salts perfectly alcalised, differ not from each other in 

 sensible, nor, so far as I have had opportunity to enquire, in hidden properties. 

 It has been a constant and general persuasion, that many fixed salts do retain 

 some, at least, the specifical properties of those vegetables, out of whose ashes 

 they were extracted. The salt of wormwood and mint are said to be stomachi- 

 cal; that of the greater celandine proper for icterics ; those of broom, ashkeys, 

 elder, bean-stalks, &c. diuretical; of rosemary, sage, &c. cephalic; and others, 

 too many now to enumerate, which are thought to be endowed with very dif- 



VOL. II. Y 



