The asphalte rock is first crushed in a “Blake’s” or other suitable crusher, then pulverised in what is known as a “Carr’s disintegrator,” until it is reduced to a powder; this powder is then heated up to between 212° and 250° Fahr. in revolving cylinders and is laid about 2¹⁄₂ inches in thickness upon a concrete foundation previously prepared for its reception, the powder is carefully raked to the required contour and then either rolled or punned with iron punners previously heated to prevent the adhesion of the powder to them. A roadway thus prepared presents many advantages over macadam, granite setts or wood, the following passage amply describing one of them:[92] “An indispensable feature of a weight-carrying pavement must be the absolute exclusion of water at the surface as nearly as it can be insured, and in this one respect it cannot be questioned that a surface like asphalte has no equal, the absorption being so gradual as to be inappreciable during any possible continuance of moisture.” In addition to this indisputable fact the advantage of durability is claimed for asphalte, but this must vary considerably with the quality of the material and of the work. Mr. Hayward estimates the life of an asphaltic Val de Travers compressed roadway at 17 years, and it is claimed for it that it will wear until it becomes quite thin, very heavy traffic breaking it up when it is worn to about ³⁄₄ of an inch thick. Another advantage claimed for asphalte is cleanliness, and this is evidently indisputable, as, being impervious, none but imported mud or dust can be formed upon it. In addition to the foregoing the following advantages are also claimed: Pedestrians can walk on asphaltic roadways as well as on the footways. It is comparatively noiseless under traffic, though in this case wood is better, as the clatter of the iron-shod horses’ feet upon asphalte is very apparent. It is expeditiously laid, and when repairs are necessary they can easily be effected; no pavement shows less signs of openings being made in it for gas and water-pipe repairs than asphalte. The rapid laying causes less inconvenience to traffic in the streets. Ease of traction; but here steps in the one great objection to asphalte as a roadway paving, viz. danger to horses by slipping and falling, of which I shall say more hereafter. Cellars and vaults under the streets are kept dry, by reason of its impermeability to moisture. Easily cleansed, especially by mechanical sweeping, and snow is easily removed. It is very pleasing to the eye, being so uniformly regular and of good colour. There is no vibration or concussion in travelling over it, and apart from the question of safety it is delightful to drive over it. It is a cool pavement at night; it does not absorb heat during the day, and consequently none radiates from it after the sun has gone down.[93]