Polytechnic Association. 679 



7. The kitchen floors can be formed of concrete, having a neat and 

 clean appearance. 



Cement stones have fllso been largely employed for constructions in 

 the sea, especially for harbor dams, breakwaters and quay walling. 

 "We refer to the moles of Dover and Alderney in England, of Port 

 Yendre, Cette, La Ciotat, Marseilles and Cherbourg in France, of 

 Algiers and Port Said in Africa, and to those of Cape Henlopen at 

 the mouth of the Delaware. For the breakwater at Cherbourg (one 

 of the most remarkable), artificial stone blocks of 712 cubic feet each 

 were immersed. The harbor of Cherbourg being exposed to heavy 

 gales, the largest blocks of natural stone which could be brought from 

 the shore would be mere play balls of the waves. There are instances 

 known where blocks of thirteen cubic yards were not only pushed far 

 above the slopes, but also turned over at the head of the mole ; hence 

 the necessity of employing blocks of immense size. Such blocks can 

 scarcely ever be obtained from quarries, to say nothing of the diffi- 

 culty and expense of transporting them. 



To speak of other uses of hydraulic mortar, I will mention that the 

 beautiful fortifications before Copenhagen are wholly constructed of 

 beton, and competent artillerists assert that for fortifications it is far 

 superior to any other work. This beton is more largely used for 

 foundation walling, especially in water, for sluices, aqueducts, bridges, 

 floors, sidewalks, terraces, roofs, cisterns, reservoirs, water pipes, etc. 

 The first sluice which was entirely built of concrete is the Francis 

 Joseph sluice on the Danube, in Hungary. This work forms a reser- 

 voir, the bottom and the sides of which consist of one piece. Its 

 length is 360 feet and width thirty feet. Its construction, begun in 

 1854, was completed within ninety days, the work being pushed for- 

 ward both night and day. 



Of unusual interest in the line of structures of beton, because 

 demonstrating their great strength, is the monolithic test arch of St. 

 Denis, near Paris. This arch forms, like the Francis Joseph sluice, 

 one piece. The material used is known at the heftm agglomere, 

 systbne Coignet, the last being the name of the inventor. The span 

 of the arch is 196 feet, its elevation nineteen feet, and length forty- 

 nine feet. The stone possesses a fine texture, and is perfectly imper- 

 vious to water. 



M. Coignet's system of " monolithic construction " has also been 

 applied for the erection of the aqueduct of La Vanne, which now car- 

 ries pure water from the river of La Vanne, in the department of the 

 Aube and of the Yonne to the city of Paris. The distance from 



