Gravel, in agriculture and gardening, is a congeries of pebbles ; which, if mixed with stiff loam, make excellent and durable gravel-walks. For this purpose, the bottom should be laid with lime-rubbish, large flints, or any other hard substance, to the depth of six or eight inches, in order to prevent any weeds from shooting through the surface. Over this stratum, the gravel is to be strewed six or eight inches thick, and somewhat sloping, that all the larger stones may roll off to the sides. The next operation is that of raking, when the large* stones are to be removed, and the walks carefully rolled in every direction, especially during or after hard showers : thus they will bind, and become very firm.

The most proper gravel for walks, is that which abounds with smooth round pebbles; for these, when mixed with a small portion of loam, are not so liable to be turned up by the feet in walking, as those of a rough and irregular shape.

Gravelly Lands or Soils are such as abound with gravel or sand, which easily admit both heat and moisture. They receive but little benefit from the latter, if there be a loose bed at the bottom, because it easily evaporates; but, if the stratum be firm, for instance, clay or stone, the moisture is too long retained, so as to chili the soil and render it unfruitful. The best method of counteracting this in-convenience, is to manure such land with chalk, which is slightly to be ploughed in, that it may not sink too deep into the ground.

As gravel constitutes the chief material of our roads, and thus becomes an article of considerable importance, we shall briefly men-tion a method, by which gravel or, stone may be discovered without loring. It simply consists in observing, whether the Common. White Saxifrage, or Saxifraga granulata,L. (which see) grows on any spot where a bed of gravel is suspected to lie : for, if .that plant be discovered, it will serve as a guide to surveyors or others, where to dig with a certainty of finding the object of their search. We. state this fa6t on the authority of Mr. T. WALFORD,in the 25th vol. of Annals of Agriculture, where an accurate representation of the Saxi-frage is given, - For a method of clearing land from stone or gravel, we refer the reader to the article Stone.