DRAWING.
The size of horses should be in proportion to the weight and size of the vehicle and loads they are intended to move, upon the principle, easily demonstrated by experiment, that weight drags weight. For instance, a horse having to drag a cart up a hill, will do so more easily with the driver on his back than otherwise, as the weight of the man assists the horse against the weight he has to move. The latter part of this argument only refers, however, to short distances, or to starting a draught.
The higher the wheels are, and the closer together, whether they be two or four, the lighter will be the draught. In fact, to render the draught as easy as possible, the axles ought to be on a level with the trace-hooks, or point of traction, or as nearly horizontal as possible with the traces and their place in the leg of the hames. It is self-evident that if a horse has to be pulling up, it is like his having to raise a certain part of the weight of the carriage with every step he moves; and the faster he goes, the more injuriously does this principle operate against him.
The point of the pole-and-chain attachment should be always so elevated from its insertion in the carriage as to be on a level with the rings of the hames through which the pole-chains pass. On the point of the pole should be a revolving steel cross-tree, from eight to ten inches in length, in the ends of which the pole-chains or leathers are inserted. The working of this contrivance will, to any practical man, demonstrate its utility.
In light double harness, I much prefer using swinging-bars instead of one inflexible splinter-bar, unless for very heavy draught. Horses should be placed close to their work. For adjusting the traces to that effect, [see page 58].
It should be remembered that the farther forward in a carriage the weight to be drawn is placed, the easier will be the draught on the horse. Thus the weight of one man at the extreme end of the vehicle (like a conductor on an omnibus) has as much effect on the traction as that of two men on or near the driving-seat. The deader the weight, let it be placed as it may, the greater the trial of the horse; therefore inanimate matter is heavier on traction than anything having life.
Vehicles of which the lower carriage and axles are kept braced together by a perch steadying the action of the wheels, are much the easiest on the draught. The Americans are well aware of the advantages of such a construction for encountering the roughness of many of their roads. Not only are all their pleasure carriages, or “buggies,” so constructed, but the waggons have a perch that by an admirable arrangement can be detached, to allow of the carriage being lengthened when required to carry timber or other lading. The perch, being in two pieces, can be coupled by the simple contrivance of a movable iron band and pin, giving a freedom, most desirable in a rough country, to the movement of the lower carriage. This contrivance works well, and might with advantage be applied to our military train-waggons and ambulance-carts. Horses cannot but suffer from the present construction of carriages in general use, where the axles are left unsupported and unbraced to encounter the roughness and inequalities of the road.
Axle-Boxes.—Proper lubrication of the axle-boxes is too often sadly neglected. Even Collinge’s patent will not run freely without periodical aid in proportion to use, and it is no harm to make an occasional examination of the wheels of a carriage when they are lifted off the ground by setters, to see that there is thorough freedom in the working of them, by spinning them round with one’s finger against the spokes. The reapplication of gutta-percha or leather washers is essential, as the amount of friction by work will wear that requisite.
For a few days after the washers are replaced, the boxes should not be screwed too tightly, but subsequently they should be re-tightened. The noise of wheels joggling upon their axles indicates want of screwing up, or of washers.
A round tire is decidedly easier for draught than a flat-edged one.
Carriages, immediately after use, should be cleaned, or at least have water dashed over them, to prevent the mud from drying on the paint, which can scarcely fail to deteriorate it, and give it a premature appearance of wear.