Road, an open way, or public thoroughfare, which forms a communication between two distant places.
Roads being frequently disfigured, and otherwise injured by the deep ruts which are necessarily made by the continual passing and re- passing of narrow wheel-carriages ; various machines have been contrived, with a view to facilitate the repairing of highways, and to fill up such excavations— From these, we shall first communicate the Road-Harrow, invented by Mr. Harriott, to whom the Society for the Encouragement of Arts, etc. in 1789, voted a reward of ten guineas.—As this machine may not only be employed with great advantage, by the surveyora of public roads, but will also be found very serviceable in repairing and improving the private ways, or avenues, belonging to manors, we have annexed the following representation :
The model, from which this cut has been executed, is on the scale of two inches to one foot; so that the head of the harrow is three feet wide from one side of the bar to the other, externally. These bars are four inches square ; five feet long; and, to prevent them from being split, they are contrived lengthwise, instead of being in a transverse direction. The mould-boards are four feet two inches in length, ten inches in depth, and two in thickness : they extend 11 inches beyond the bars, in order that the stones (which are brought to the surface by the teeth of the harrow) may be drawn into a smaller compass. These mould-boards are, farther, shod with ah iron-bar, and lined with a plate of the same metal, to the height of the Spot where they are marked black, in the cut above annexed; and such parts of this delineation, as are represented of a deeper colour, distinguish the iron from the woodwork. The teeth are one foot in length from the inferior side of the bars to their points, which ought to be steeled : they are 1 1/4 inch square, and are fixed by means of strong nuts and screws, With collars both oh the tipper and lower side of such bars.
Mr. Harriott's road-harrow is drawn by two horses abreast: the outside animal is led by a boy on that quarter; while the other horse walks in the proper path, and a man keeps the harrow steady by the handles: consequently they take one inside and one outside quarter in their progress, and the remaining two quarters in their return.
By this excellent machine, a man, boy, and two horses, may with ease repair three miles in length, in one day; harrowing down the quarters, and drawing the stones together, Which are dropped into the ruts, by means of the mould-boards, in a more effect tual manner than if they were stub-bed in by a man. Lastly, the work is performed not only more expeditiously, but also at one-tenth part of the expence incurred, when the roads are repaired by manual labour.
In the 8th volume of the Re-pertory of Arts, etc. we meet with an account of a contrivance for preventing the wheels of carriages from making ruts in roads, K by Robert Beatson, Esq.—This object is effected by fixing between the other wheels a protector, or small roller, or broad wheel: the circumference of its upper part should be about 1 1/2 inch beneath the axle-tree, while the lower one ought to be at a similar distance from the ground. Such rotler must be secured to the axle-tree, so as to be able to support the whole weight of.the carriage, in case the principal wheels descend into any deep ruts. The size of the protector varies according to the proportions these wheels ; but Mr. B. observes, that two feet in dia-meter will be sufficient for single carts; and that double carriages, or waggons, will require it to be rather larger and broader, By thus elevating the roller a little distance above the lower surface of the wheels, the latter will,on good roads, support the weight of the load; and, if the middle or horse-path be firm, they cannot sink into old, or form any new, ruts ; because the protector will roll in the middle, and thus afford an easier draught to the cattle. The additional weight of the machine, if it be properly constructed, Mr. Beatson con-ceives, will be inconsiderable; when compared with the utility of such contrivance, and the great reduction in the expence both of making and of repairing roads.-A more comprehensive account of this invention, the reader will find in the work above cited, where it is farther illustrated with an en-graved figure.