OF EARTH. 



35 



Here now, of course, we are to say something concerning calcinations, 

 all reducing of stone into ashes being of excellent use where lime is upon 

 any occasion proper ; and indeed all our composts and dunging serve 

 but to this end, namely, so to qualify and mix the soil as may artificially 

 answer to the varieties of the natural earth, or such a constitution of it as 

 the skilful husbandman requires : as for instance, (since all fertility is the 

 result of mixture contrary in quality,) if it want due heat, to apply addi- 

 tions of a fiery nature ; and therefore it were profitable, if in the using 

 lime with turf and swarth, it were laid alternatively, turf on lime, and lime 

 on turf, in heaps for six months, by which means it will become so mel- 

 low (and rich in nitrous salts) as to dissolve and run like ashes, and carry 

 a much more cherishing vigour than if amassed in greater quantity ; and 

 so, by a too violent application, burn out and exhaust the vegetative virtue 

 which it should preserve. There is (by the way) this caution to be used 

 in burning of earth, that though what is torrified into blackness will ex- 

 ceedingly fructify ; yet if it proceed to adustion beyond that degree, it 

 consumes the nitre, which is the principle that should be preserved; as we 

 shall come to shew when we speak of salts, which we are the most care- 

 fully to keep entire in all our animal or other composts 



This husbandry (long since used by the Romans, even in Britain, but 

 discontinued after their expulsion) was revived in Flanders ; from thence 

 it was brought into Devonshire, and about sixty years after cultivated 

 more generally. It had great success at first, (especially on chalky and 

 barren grounds,) but sensibly diminishing, occasioned the proverb that, 

 " What is good for the father, is sometimes naught for the son ;" how- 

 ever the fertility is again restored, by feeding sheep upon the ground ; 

 a dressing; of all others the most desirable. 



Two loads of turf will make a load of ashes, which, spread on steril 

 lands, spontaneously produce the Cinquefoil Lime, a little sleeked, is 



* Turf reduced to ashes by a vehement and open fire, forms a hard substance called glass ; 

 so that burn-baking, under such circumstances, can do no service, the vegetative powers 

 being changed into a body incapable of the least solution in any menstruum. A moderate 

 and confined heat, on the contrary, reduces the vegetable substances contained in the turf, 

 to an alkaline salt, well known to be a great promoter of vegetation. 



' My very worthy friend. General St. Leger, has communicated to me the following 

 experiment, which, with great exactness, ascertains the quantity of ashes to be obtained 

 from an acre of land by burn-baking. " In August, 1767, I pared and burnt one acre 



3 K2 



