ASPHALT PAVEMENTS. 611 



stone falls to powder, and may then be dissolved in hot melted bitu- 

 men. 



This substance does not occur very abundantly in Nature, the only 

 deposits of any importance, so far as yet known, being found in the 

 Val de Travers and at Seyssel, in Switzerland ; Seefeld, in the Tyrol ; 

 Lobsan, in Alsace ; Holle, in Holstein ; and Limmer, in Hanover. The 

 deposit at Holle is by far the most extensive in Europe ; but, though 

 here the particles of the limestone are thoroughly permeated by the 

 bitumen, the material is not considered by the Paris Asphalt Company 

 to be suitable for pavements, because it contains an excess of pure pe- 

 troleum. Yet Dr. Meyn thinks that by exposure to air the greater 

 part of this surplus may be dissipated, and the remainder oxidized. 



Ancient authors state that Babylon was partly built with asphalt, 

 and that an asphalt cement was used for the walls of Nineveh. A 

 Greek physician, Eirinus, endeavored to bring this substance into use 

 as a buildinsr material in 1712. He was the first to discover a method 

 of reducing the asphalt of the Val de Travers to the liquid state, 

 and obtained the monopoly from the King of Prussia of all the asphalt 

 beds he might ^discover in the principality of Neufchatel. He pub- 

 lished in 1721 a "Dissertation on Asphalt," in which he gives as fol- 

 lows the process of making asphalt cement : " The preparation of this 

 cement is very easy. The stone must be slightly warmed till it can 

 be coarsely powdered. A small quantity of pitch is added, to make it 

 thinner and more soluble, and then the whole is melted over a slow 

 charcoal-fire." This cement was to be used instead of mortar, and 

 also to protect wood and stone-work against decay. There is still to 

 be seen at Couvet, a little village in the Val de Travers, a flight of 

 stone steps, dating from the time of Eirinus; the lower steps are 

 coated with asphalt, and are almost entirely unimpaired, while the 

 upper ones, which were not so protected, are worn into holes. But 

 the material did not continue long in use for building purposes, for in 

 1802, after the discovery of asphalt-stone at Seyssel, near Geneva, we 

 find the preparation of a mastic, from bituminous limestone and tar, 

 heralded as a new invention. 



In 1832, the Seyssel quarries fell into new hands, and from that 

 period we date the progress made in the matter of asphalt pavements. 

 The new proprietor of the quarries, Count Sassenay, devoted himself 

 exclusively to producing a continuous and homogeneous material, and 

 carefully instructed his workmen in the best manner of laying this 

 pavement. The celebrated foot-path of the Pont Royal, the fine pave- 

 ment of the Place de la Concorde, Paris, as well as many pavements 

 at Lyons, belong to that period. Sassenay's process is still employed 

 in preparing asphalt for paving foot-paths, and the mode of laying 

 down the pavement is as follows: The foundation must be even, 

 for any inequality of its surface will cause the pavement to wear out 

 more rapidly in some parts than in others. The mastic is broken into 



