hment of the draft
The draft-rod, extending from the clevis to the sheth.
Many modifications are found.
The colter is sometimes a wing from the upper forward edge of the mold-board; or it is a cutting-wheel in advance.
The draft-rod is not universal, but adds to the strength of the implement.
The mold-board was, as its name indicates, formerly of wood.
It was first made of iron by Small of Berwickshire, Scotland, about 1764.
The chilled cast-iron plowshare was patented by Ransome of Ipswich, England, 1803.
The under side and points are hardened, and the top wears away, leaving a comparatively thin edge of hard, chilled iron.
This is an imitation of the provision of nature, whereby the teeth of the rodentiae are kept sharp, the external enamel keeping in advance of the softer parts which are sloped away from the cutting edge.
The points to be aimed at in the construction and management of a plow are as follows:—
A sharp, clean tapering form to the part which
ammed, I can assure you, does continue for years in an imperishable state, and is neither affected by rain, by wind, nor by fire, and neither mortar nor cement is used in them.
These must have been what are now termed pise--work (which see).
Ransome's process (English) for rendering walls impervious to moisture is as follows:—
The external surfaces of the walls to be protected are first washed with a silicate of soda or solution of flint, which is applied again and again, until the bricksulted:—
No.Name and Year.
4,560.Von Schmidt, 1846.
49,382.Cooley et al., 1865.
4,158.Samuels (reissued), 1870.
65,545.Constant et al., 1867.