THE TECHNOLOGIST. [June 1, 1864. 



OZb COMPRESSED ASPHALTE. 



as far from being obtained as ever. Then followed the difficulties of ap- 

 plication, and in this department the experiments conducted in the Rue 

 Neuve Petits Champs were fertile in instruction. The asphalte used 

 was hard and unmanageable ; the season far advanced, and it was a 

 matter of some difficulty to procure a dry surface of concrete for the 

 asphalte to rest on. The moisture was evaporated by the heat, and per- 

 vading the mass, prevented the efficient agglomeration of its particles. 

 Worst of all, the concrete itself reposed on soil recently disturbed in 

 the formation of a sewer, and the settlement which followed, as a 

 matter of course, led to the rupture of the bed of asphalte. Ultimately 

 all these obstacles were overcome, and M. Malo states the advantages of 

 the new roadway as follows : — It produces neither mud nor dust ; the 

 annual wear equalling only one millimetre, once it has become thoroughly 

 consolidated by the passage of vehicles. It is almost perfectly noise- 

 less — no trifling advantage, be it remarked. What would not. we 

 dwellers in London give for a noiseless pavement ? The labour of 

 horses is materially lessened on the compressed asphalte, as compared 

 with stone paving or macadam ; a fact disputed, however, by M. Tresca, 

 a gentleman who has conducted a valuable series of experiments on the 

 tractive resistance of various roads. The expense of maintaining wheel 

 carriages in repair is considerably reduced by the suppression of ruts 

 and jolting. M. Malo stated the saving at 8,500,000 francs, supposing 

 all Paris asphalted, yearly ; and, lastly, the absence of vibration tends 

 to the durability of the houses on either side. In opposition, it has 

 been urged that the new pavement is too slippery for smoothly shod 

 carriage and saddle horses {clievaux de luxe). According to M. Malo, 

 this inconvenience is never experienced unless the curvature of the 

 road is exaggerated, or on steep hills. This has been verified by expe- 

 rience. It was stated that one horse in 1,308 fell in passing through 

 the Rue de Seze, which is paved, and but one in 1,409 in passing 

 through the Rue Neuve des Capucin, which is asphalted. Sometimes, 

 however, the surface is rendered slippery by the presence of foreign 

 substances dropped in traffic. A simple washing removes the evil. 

 The same end may be attained by means of a slight sprinkling of sand. 

 M. Malo estimated the cost of the different roadways used in Paris 

 at the following rates per square metre : 



Material. Formation. Annual Maintenance. 

 Compressed Asphalte 



and Concrete 15f. If. 25c. 



Pavement of Belgian 



Porphyry lOf. to 22f. Of. 50c. to If. 50c. 



Macadam 7f. 2f.40c. to 3f. 



M. Malo concluded by stating that all the Jura district, from the 

 department of the Bas Rhine to Savoy, abounds in asphalte, so that no 

 fears need be entertained of exhausting the supply by extending the 

 application of the material. 



