1 36 Literary and Philosophical Society. 



summers, must certainly leave a mud of the same kind 

 and quality. 



* Putrid juices and putrid vapours are dispersed through 

 the earth and air, so that there are few earths of an 

 absorbent kind that are not, in some degree, nitrous. 



P. 197. 'Glauber, who, from the observations he had 

 made upon the fruits and effects of the bottoms of stinking 

 ditches, seems to be the first that attempted to form arti- 

 ficial nitre beds, threw into pits, covered from the rain and 

 sun, but exposed as much as possible to the air, all sorts of 

 dung, with the cuttings of trees, refuse of gardens, and other 

 putrid and putrefiable matters, to which he added wood- 

 ashes ; and, by this means, in a course of time, obtained, 

 not a mere nitrous, but a true saltpetre earth, that afibrded 

 him the crystals of this salt upon simple elixiviation and 

 evaporation. 



* It does not appear that this celebrated chemist had 

 the least idea that these putrid matters were of any other 

 use than to draw the nitre, as he called it, from the air, in 

 which the fixed salt of the wood-ashes might possibly 

 assist.' 



P. 201. ^ About thirty years ago, an ingenious chemist 

 of our own nation, having visited many of the great works 

 abroad, and made the observation, that to form a nitrous 

 earth nothing more appeared to be necessary than to mix up 

 calcareous earths with any kind of dung, and expose these 

 materials to the air, returned home, fully persuaded that he 

 was master of the secret, and had interest enough to prevail 

 upon many of his friends to join him in erecting a large 

 saltpetre works, at Fulham, near London. Here many 



