Fixed P^egetaUe Alkali, ^c, 7'^ 



decayed and decaying parts of vegetables, ad- 

 vanced and advancing to the ftate of putrefacflion.: 

 As it appears, therefore, that true nitre is pro- 

 duced in this procefs, it is obvious, that the 

 vegetable alkali is produced by the operation of 

 nature only, in the putrefacflion of vegetables. 



That nitre is produced in the putrefaction of 

 animal matters, has been confidently afierted by 

 fome chemifts, and as confidently denied by 

 others. Inftances are alledged on the one hand, 

 of nitre procured from putrefied blood, urine, 

 &c. On the other hand it is argued, that thefe 

 fubftances will not fupply the materials of nitre, 

 without the concurrence of fome vegetable 

 matter. To difcufs this point thoroughly, would 

 take a great deal of time, and requires extenfive 

 abilities; but I think there is a common and 

 familiar fact, which may be adduced to illuftrate 

 it. It will at lead prove, that if nitre (and of 

 courfe the vegetable alkali) is not obtainable 

 from the putrefaftion of animal matters only, 

 the addition of a very fmall quantity of vegetable 

 matter is fufficient for its production. I aro-ue 

 from the quality of the faline efflorefcence found 

 on old walls, which are expofed to impregnatioi/ 

 from animal matters in a (late of putrefadion. 

 The wall of one end of my chemical fchool, or 

 laboratory, is almoft entirely covered with 

 fuch an efflorefcence. The laboratory, is a 

 large vaulted room under ground, into which 



the 



