ADDITIONAL NOTES. 595

plough is only to pafs under the foil, and thus loofen it, and mix it With atmofpheric air without turning it over.

By this manœuvre the clay a few inches deep beneath the fertile foil becomes broken in its texture, and obtains fome air intercepted in its pores; from the former circumftance it may contribute to retain the vernal fhowers, which would otherwife run off over the clayey furface beneath the more fertile one, and might thus in drier feafons prevent the upper furface from being fo much indurated, and mioht gradually become lefs injurious by the frequent admixture of atmo-

fpheric air, and at length even falubrious to the roots of vegetables.

462: APPENDIX:

RS

SR 2 mi 2 p——… es em m4 masses 5

ris

PAR> qe mg