152 $be Principles of Part III. 



Exp. 37. To put this queftion beyond 

 all doubt, I took from a molehill fome rich 

 foil in the month of Otober> poured water 

 on it, and filtered that water through brown 

 paper. This liquor, when boiled up, was 

 yellow, and tafted faline. The fait ap- 

 peared plainly to be nitrous ; as brown 

 paper, dipt in this liquor, and dried, burnt 

 like a match. On an addition of ol. tart. 

 p. d. the liquor turned milky, and let fall 

 a white powder ; which mows the fait to be 

 of the fame nature with that of hard water. 

 At firft, I could get no fait by cryftallifation, 

 as the liquor was very unctuous, and in 

 fmall quantity* But on treating it in the 

 fame manner as the manufacturers do the 

 materials of nitre, viz, adding fome quick- 

 lime to feparate the oil from the falts, and 

 allowing it to (land fome days, I got from 

 it a true faltpetrc. This experiment 

 mows the faline part of the vegetable food 

 to the eye. 



