which are typical of the block type. The price of many of the American makes of scarifiers is about $500 f.o.b. factory.

The scarifiers of Europe are of two types, one of which is similar to the block type as illustrated in Fig. 92, while the other is attached to the rear of a three-wheel roller and is a part of the roller, as illustrated in Fig. 94. It consists of a framework supporting a small block in which the picks are inserted. The

framework is attached to the rear of the roller so that the pick block is behind one of the driving wheels and the picks are set at such an angle that they are forced into the road by the force of the roller and the weight of the block. The advantages of this type of scarifier are the ease with which it is handled and the saving in time obtained by having the scarifier so attached that it can instantly be put into operation when the roller is traveling in any direction.

Watering-Carts. In the United States the cart used for sprinkling generally consists of a cylindrical tank mounted horizontally on a four-wheel truck. The tank may be made either of wood or of steel. The capacities vary from 350 to 1,000 gallons. The size generally used in constructing broken stone roads

is either 450 or 600 gallons. The wheels are usually made so as to track, and the standard width of tire is from 3 to 4 inches. Many of the manufacturers, however, make one type which is particularly adapted to constructing broken stone roads in which the tires are 6 to 8 inches wide and the wheels overlap. The discharge valves are of two kinds, either horizontal or vertical. The horizontal valve throws water out in a horizontal sheet, while

the vertical valve throws it in a vertical sheet. Fig. 95 illustrates a watering-cart typical of those used in the United States. The cost of a 600-gallon watering-cart is about $350.

Many of the watering-carts used in England and France have a rectangular instead of a cylindrical tank. The tanks are also usually made of steel with capacities ranging from 200 to 400 gallons.

Stone Forks and Rakes. Heavy tine forks will be found useful in handling large-size broken stone, particularly when the stone has been dumped on the ground. The fork can be filled more easily than a shovel, and no dirt will be taken up with

the stone. A two-handle rake, the handles being arranged on either side of the rake head so that as one man pulls another can push, is used for levelling and spreading stone. Ordinary

potato hooks are also useful in pulling down piles of stone or in smoothing out the surface.

Road Scrapers. Stone can be economically spread from heaps by means of almost any of the types of road machine scrapers described in Chapter VII.

CHARACTERISTICS.

An ordinary macadam road, if properly built of the right kind of stone, is a very economical and satisfactory surface for medium horse-drawn vehicle traffic. It affords an excellent foothold, is noiseless, does not offer much resistance to traffic, and is comfortable to use. In dry weather, however, a macadam surface is extremely dusty unless the surface is treated with a palliative or coated with bituminous material.