Roller, a well-known implement of agriculture, the cylinder or" which consists either of stone, wood, or iron.

The principal design of rolling land, is to render loose soils more compact; by which means the earth adheres closely to the roots of plants, and their growth is considerably promoted. The season for performing this operation, varies according to the nature of the soil, and of the vegetables to be raised. Thus, it is an object of considerable importance, to roll wheat in the months of October and November, and from January till April, especially if the ground be loose; because the winter-rains frequently press the soil down, and thus leave the roots uncovered; and the autum-nal rolling will prevent the ill ef-fects of frost, as the spring-rolling will obviate those arising from droughts. Farther, it will be ne-ce-sary to pass the machine over land sown with barley, directly after the seed is scattered. Oats, also, particularly on light soils, should be thus treated, immediately after sowing ; but, in clay-lands, the operation ought to be deferred till the grain appear above ground. Lastly, all grasses may with advantage be rolled once, early in the spring ; and, if it be practicable, a second and even a third time, after irrigation ; because the earth will thereby not only be rendered more firm around the roots, but this management will also facilitate the future mowing. - See Pasturage,