OF EARTH.

55

Here now of course we are to say something concerning calcinations,all reducing of stone into ashes being of excellent use where lime is uponany occasion proper; and indeed all our composts and dungings servebut to this end, namely, so to qualify and mix the soil as may artificiallyanswer to the varieties of the natural earth, or such a constitution of it asthe skilful husbandman requires : As for instance, (since all fertility is theresult 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 usinglime with turf and swarth it were laid alternatively, turf on lime, and limeon turf, in heaps for six months, by which means it will become so mel-low (and rich in nitrous salts) as to difsolve and run like ashes, and carrya much more cherishing vigour than if amafsed in greater quantity; andso, by a too violent application, burn out and exhaust the vegetative virtuewhich it should preserve. There is (by the way) this caution to be usedin burning of earth, that though what is tovrified into blacknefs will ex-ceedingly fructify; yet if it proceed to adustion beyond that degree, itconsumes the nitre, which is the principle that should be preserved; as weshall come to show 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 , butdiscontinued after their expulsion) was revived in Flanders; from thenceit was brought into Devonshire, and about sixty years after cultivatedmore generally. It had great succefs at first, (especially on chalky andbarren grounds) but sensibly diminishing, occasioned the proverb that,

« What is good for the Father, is sometimes naught for the fonhow-ever the fertility is again restored, by feeding sheep upon the ground; a-drefsing of all others the most desirable.

Two loads of turf will make a load of ashes, which, spread on stevillands, spontaneously produce the Cinqfoilh Lime, a little sleeked, is

s Turf reduced to ashes by a vehement and open fire forms a hard substance called ol a f s .fo that burn-baking, under such circumstances, can do no service, the vegetative powersbeing 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.

1 My very worthy friend, General St. Leger, has communicated to me the followingexperiment, which with great exactnefs afcerlains the quantity of ashes to be obtainedfrom an acre of land by burn-baking. “ In August, 1767, I pared and burnt one acre

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