in natural history and gardening, a congeries of pebbles, which, mixed with a stiff loam, makes lasting and elegant gravel-walks; an ornament peculiar to our gardens, and which gives them an advantage over those of other nations.

in medicine. See the Index subjoined to that article; and see ALKALI, no. 17.

GRAVEL-WALKS. To make these properly, the bottom should be laid with lime-rubbish, large flint-stones, or any other hard matter, for eight or ten inches thick, to keep weeds from growing through, and over this the gravel is to be laid six or eight inches thick. This should be laid rounding up in the middle, by which means the larger stones will run off to the sides, and may be raked away; for the gravel should never be firmed before it is laid on. It is a common mistake to lay these walks too round, which not only makes them uneasy to walk upon, but takes off from their apparent breadth. One inch in five feet is a sufficient proportion for the rise in the middle; so that a walk of 20 feet wide should be four inches higher at the middle than at the edges, and so in proportion. As soon as the gravel is laid, it should be raked, and the large stones thrown back again; then the whole should be rolled both lengthwise and crosswise; and the person who draws the roller should wear shoes with flat heels, that he may make no holes; because holes made in a new walk are not easily remedied. The walks should always be rolled three or four times in very hard showers, after which they will bind more firmly than otherwise they could ever be made to do.

Gravel, with some loam among it, binds more firmly than the rawer kinds; and when gravel is naturally very harsh and sharp, it is proper to add a mixture of loam to it. The best gravel for walks is such as abounds with smooth round pebbles, which, being mixed with a little loam, are bound to firmly together, that they are never afterwards injured either by wet or dry weather. These are not so liable to be turned up by the feet in walking, as the more irregularly shaped pebbles, and remain much more firmly in their places after rolling.