54 Additions and Correéfions

driven into the poft with its point upwards in the commen way, and the point of the other hook in the contrary diretion, which is an effectual mode of keeping the gate on its hinges; but it has the inconvenience of not permitting the gate te be removed without drawing one of the hooks.

The fame principles are applied in the hanging of gates on the contrary fides, and

likewife to thofe of fwing-gates; full explanations of which may be fecn in the very ufeful Eflay referred to, as well as the methods of fawing timber for gates and gate- potts. The methods of hanging and fafiening, as well as the inconveniencies of fwing- gates, are alfo explained with great ingenuity and practical accuracy; but they will be beft underftood by perufing the Effay, as they cannot be fully comprehended without the plates.

Mr. Parker has likewife found, that cafi-iron may be applied with fuperior ad@- vantage to the purpofe of hanging and faftening gates, the hooks being attached to: the pofts by means of fcrews, infiead of being driven in as in the uftal mode. By this meansit is fuppofed that a faving of at leaft fifty per cent may be made. Com- plete fets of which are furnifhed by Meftrs. Deermans, Francis and Company,

‘agle Foundry, Birmingham.

To be read after Line 4, Page 152.—In the above refpect it, appears that roads formed on the model of a gently-inclined plane have an obvious ad- vantage; for the very ruts which the wheels make ferve as channels to con- duct the water down the defcent; at the loweft point of which a tranfverfe groove fhould be kept open to convey it into the ditches on either fide. So extremely gentle is the xeceffary defcent, that grooves at the diftance of one hundred and fifty yards will be found in moft cafes fufficient. The water has thus feventy-five yards to run, and the elevation need not be above eighteen inches, or two feet. It is commonly to be obferved, that the convexity of a road is inverfely proportioned to. its narrownefs. Turnpike roads of the full ftatute width, unlefs unufually fhadowed by trees, receive fo much fun and air, that they are kept tolerably dry without much convexity of their farface. Narrow roads and lanes are only to be kept dry by ar- tificial means, and fometimes the convexity is fo extremely great, as to render the paffing of two loaded carriages extremely dangerous. Perhaps the gentle convex fhape is preferable for turnpikes, but the fhape of the longitudinal-inclined plane

has many advantages in narrow lanes,&c.

To be read after Line 6, Page1s8,.—The cafes where it would be neceffary to.carry off the water every ten or fifteen yards muft be extremely rare; perhaps there are

ten ban tui¢ cum and empl their wave the c: tend of the to be f contin

from 4 current In fo portion the inn¢ buttre(s, dertee of the wate pend,| oa perp beoppok In ref}| bank can

Water, the