OF EARTH. 



53 



advance them at all ^. It should, therefore, be considered, whether any 

 salts do universally nourish all plants alike ; or rather partly, some one 

 plant, some another : for upon the clear decision of this secret, depends 

 all that is truly curious in this affair ; laying, as I do, for position, that 

 the improvement of all the earths and soils I have spoken of, results 

 from some salt or spirit, (call it which you please,) as from an indispen- 

 sable principle in this vegetation, and perhaps the first rudiment of life in 

 all things else ; and till we shall arrive to this, (by what I have observed 

 in the discreet use even of our common salt, brine, the effects of urine, 

 and the like,) I firmly believe, that were saltpetre (I mean factitious nitre) 

 to be obtained in plenty, we should need but few other composts to me- 

 liorate our ground ; since whether that which so fertilizes it, by any mix- 

 ture we can yet devise, effect it from any other cause, is greatly to be 

 doubted; nor do I think but the charge of extracting it (at least sufficient 

 to impregnate water in convenient quantity) might be compassed by the 

 industrious farmer without much inconvenience or difficulty, were he 

 competently instructed in the process of calcination, resolution, percola- 

 tion, evaporation, and separation, put into honest English, and easily to 

 be learned : soon we should then see that this were not to be extracted 

 altogether out of stinking dung, and found in heady trash, (which yet is 

 material,) but rather in the well-impregnated and natural mould itself, 

 charged with a more generous spirit, or medicinal nitre, (in congress with 

 a certain sulphur,) capable of warming and exciting to vegetation, beyond 

 all we can promise from any mere artificial ferments, much less our com- 

 mon mixtures and ways of stercoration, which, in time, grow cold and 

 languish, and are so quickly checked 



8 Without multiplying distinctions^ we naay divide manures into four kinds : 



1. Such as give nourishment only ; as rape-dust, soot, malt-dust, blood compost, horn^ 

 shavings, pigeons'-dung, and all top-dressings. 



2. Such as give nourishment, and add to the soil ; as horse-dung, cows'-duno-^ human 

 ordure, rotten animal and vegetable substances. 



3. Such as open the soil, and do not nourish in their own natures ; as lime, light marls, 

 sand, and vegetable ashes. 



4. Such as stiffen the soil, and, at the same time, nourish a little ; as clay, clay marls, and 

 earth. 



All the boasted compositions of nitre, and other salts, for increasing the fertility of land 

 without other assistance, are now experimentally found to be of little value. Dung, that is, 

 putrid animal and vegetable substances, constitutes the only fertilizer for the use of the 



