Destructive Agents

Many European countries have laws regulating the width of tires. In England for 100 years the law required 1 inch of tire for each 500 pounds of load, but all laws regulating the width of tires have been repealed. In France the tires of market carts vary from 3 to 10 inches in width, being generally from 4 to 6 inches, with the rear axle about 14 inches longer than the forward one. In Bavaria the legal width is as follows: In this country a number of the states have statutes concerning the width of tires, many of which take the form of a rebate, either cash or part of the road tax, to those using tires of a prescribed width. The following is the legal width in Ohio: According to wagon manufacturers about 60 per cent of the wagons used on country roads have tires 1i to 11 inches wide, those of the remaining 40 per cent being 2 to 4 inches. The broad tire is of comparatively recent introduction on rural roads in this country.

In some respects the injury by narrow tires is greater on broken-stone roads than on earth roads, since the damage can be more readily repaired in the latter than in the former; but even on a broken-stone road, there is a limit beyond which it is not wise to increase the width of the tire. The crown of the road is such that the point of contact with the road is at one edge of the tire, and it is generally conceded that no material advantage is gained in making the tire more than 4 or 5 inches wide.

Equal Axles.

Since the hind wheel follows in the track of the fore wheel, it increases the depth of the rut, and consequently increases the destructive effect of the wagon upon the road. The remedy would be to make the lengths of the two axles unequal, but this would make the wagon more difficult to manage and would also increase the tractive resistance. The advantage of not per

mitting one wheel to exactly follow another, is shown by the fact that there are no ruts at a corner or a sharp turn in the road; but it is not practicable to secure this advantage generally, either by making the two axles of unequal length or by preventing a wagon from traveling in the ruts already made.

Small Wheels.

The smaller the wagon wheels the greater the destructive effect upon the road, and also the greater the trac tive power required; but for ease of loading and convenience of management, low wheels are better than high ones. It is probably wise to permit those who use the wagons and the roads, and pay for both—usually the farmers—to determine the most economic diameter of wheels.

The wagons in ordinary use on country roads have three sizes of wheels, as follows, for the front and the rear wheels respectively: According to wagon manufacturers about 80 per cent of the wagons on the country roads have the last-named size of wheels.

Horse not Hitched Before Wheel.

On broken-stone roads, the horses' feet loosen fragments of stone, which tends to destroy the surface; and if the horses were hitched directly in front of the wheels, the stones loosened by the horses' feet would be rolled down by the wheels of the wagon. This is a matter of some moment with broken-stone roads, but is hardly practicable with earth roads. However, some teamsters hitch their horses in front of the wheel, to enable their horses and wheels to run in the beaten track made by the feet of preceding horses not hitched in front of the wheel.