[Illustration: MESSRS. AVELING AND PORTER’S 15-TON STEAM ROAD ROLLER.] [Illustration: MESSRS. GREEN AND SON’S 15-TON STEAM ROAD ROLLER AND TRACTION ENGINE COMBINED.] In Paris the Gellerat steam roller is used, and another is also known, which is manufactured by Messrs. Morland and Sons. A 15-ton steam roller costs about 650_l._ in the first place, the cost of working it &c., has been given in the early pages of this chapter. The advantages of steam road rolling may be summed up as follows:-- (1.) The saving of wear and tear to vehicles and horses. Roads should be made _for_ the traffic, and not _by_ it.[51] (2.) Economy; as it is said that a saving of from 30 to 50 per cent. is effected by reason of the roads being better made thus obviating the necessity for such frequent sweeping and scraping. (3.) The roads can be made or repaired at any season of the year. (4.) The avoidance of cruelty to horses, cattle, and sheep, as in the case of newly metalled unrolled roads. (5.) A saving of road metal. (_a_) Because it need not be broken so small. (_b_) Because there are no loose stones to be kicked about and lost. (_c_) Because there is no abrasion of the stones, only one surface of the stone being exposed. (_d_) Because no ruts can be formed in which water can lie to rot the stone. (_e_) Because a thinner coating of metal can be employed. (6.) The roller can be advantageously used for other purposes. (7.) Rolled streets have a better appearance, they are easier of traffic as having more evenness of surface and superior hardness, and it is contended that if steam rollers were more general there would not be such an outcry for other descriptions of pavement for roadways. (8.) The steam roller soon finds out the good from the bad metal for roads, it is also contended that it also does this with respect to the gas and water mains, the latter, however may be looked upon as a rather doubtful advantage. (9.) The avoidance of the necessity of the continued employment of men raking the metal into the ruts. In Mr. Paget’s valuable little pamphlet upon the subject of steam rolling[52] may be found the following remarks:--