OF EARTH. 



1 



49 



pery, fat or unctuous, and the like, which are all qualities that alone, 

 and of themselves, effect little till they are corrected and prepared ; but, 

 for that among these materials we detect the causes of fertility more emi- 

 nently than in other substances, partly from their fixed salts, or some vir- 

 tue contained in them, or rather drawn from without, and imparted to the 

 exhausted and defective earth ; and that by such a process, as by convert- 

 ing them into a chyle, (as it were) it facilitates their being insumed, assimi- 

 lated*, and made apt to pass into nourishment, promoting vegetation. 

 This obtained, the next thing is, skilfully to apply what we have pre- 

 pared ; and this, indeed, is a difficulty worthy the heads, as well as hands, 

 of the profoundest philosophers, since it requires a more than superficial 

 knowledge and penetration into causes. 



We know, indeed, that the earth is, without any artificial auxiliaries, 

 endued with a wonderful prolific virtue ; but this, for being possible to 

 decay and be lost, (at least for a longer time than our necessities can 

 support,) and from some grounds never to be expected without such 

 helps, it may be worth our while a little to consider by what expedients 

 of digestion, or other ways, the desired effect of perpetuating its vigour 

 might best be accomplished. . 



That the secret we inquire after, and which does most apparently 

 seem to evirtuate towards this end, is some vegetable salt or matter, I 

 suppose is generally agreed ; for salt it is which gives ligature, weight, 

 and constitution to things, and is the most manifest substance in all 

 artificial composts. 



It is salts which entice roots to affect the upper and saline surface of 

 the earth, upon which the nitrous rains and dews descend ; and the cause 

 that some plants, the most racy, and charged with juice, of all other (for 

 such is the vine) thrive so well among rocks and pumices, and in what- 

 ever best maintains this vital pickle. 



It is salt which makes all covered and long-shaded earths to abound in 

 fertility, and renders the dung of pigeons, poultry, and other salacious 



Volume II, 



