Some are of Opinion, ’tis because the St. Foin takes a different Sort of Nourishment to that of Corn: But that I think is disprov’d in the Chapter of _Change of Species_, where ’tis shewn, that all Plants in the same Soil must take the same Food. Mr. _Kirkham_ thinks St. Foin has no collateral or horizontal Roots in the upper Part of the Ground where the Plough tills for Corn; and therefore has no Nourishment from that Part of the Soil which feeds the Corn. This would be a very good Account for it, were it not utterly contrary to Matter of Fact, as every one may see. But so far it is right, that large[193] St. Foin draws the greatest Part of its Nourishment from below the Reach of the Plough; and what Part it does receive from the Staple is overbalanc’d by the Second Crop, or After-lease, being spent by Cattle on the Ground; different from Corn, which is very near wholly maintain’d by the plow’d Part of the Earth, and is all carry’d off. [193] For large St. Foin, being single, has large Roots, and very long, which probably descend Twenty Feet deep: Now, if we allow Four or Five Inches the Depth of the Staple, to afford a Supply equal to Two Feet below it, taking the lower Nineteen Feet Seven Inches together, upon this Computation, the Part below the Staple gives the St. Foin about Nine Parts in Ten of its Sustenance. For tho’ the under _Stratum_ of Earth be much poorer than the upper; yet that, never having been drain’d by any sort of Vegetables, must afford considerable Nourishment to the First that comes there. And besides, in such Land whose Poverty proceeds from the Rain’s carrying its Riches too quickly down through the upper _Stratum_, the under _Stratum_ must be the richer[194] for receiving what the upper _Stratum_ lets pass unarrested. [194] In light poor Land the Water carrying some impregnated Earth along with it down lower than it does in strong Land, that is more tenacious of such impregnated Particles, the under _Strata_ of strong Land are likely to be poorer than those of light Land. ’Tis well known, that many Estates have been much improv’d by St. Foin; therefore there is no occasion to mention Particulars. Only I will take Notice, that the First in _England_ was one of about One hundred and Forty Pounds _per Annum_, sown with St. Foin, and sold for Fourteen Thousand Pounds; and as I hear, continues, by the same Improvement, still of the same Value. This is, I suppose, the same that Mr. _Kirkham_ mentions in _Oxfordshire_. Another Farm of Ten Pounds _per Annum_ Rent, which, whilst in Arable[195], was like to have undone the Tenant; but being all planted with St. Foin by the Owner, was lett at One hundred and Ten Pounds _per Annum_, and prov’d a good Bargain.