210 Report on the Progress and State of Applied Mechanics. 



Brighton, built whoUy of a concrete of lime and flints, lias for many 

 years stood exposed to the full force of the waves of the Enghsh Chan- 

 nel. Blocks of concrete, hardened in boxes, have been used for the 

 building of piers and breakwaters. Many bridges have had their piers 

 founded in difficult positions, on platforms of concrete, which possess in 

 some respects the properties of lai'ge flat blocks of solid stone ; and, in 

 particular the new bridge of Westminster, designed by Mr; Page, and 

 now approaching completion, has the foundation and lower portion of 

 each of its piers formed of a mass of concrete, contained in a cast ii'on 

 casing. 



15. Amongst various artificial stones, too numerous to specify in 

 detail, mention may be made of the artificial sandstone of Mr. Ransome, 

 composed of grains of sand cemented together by a sort of glass, and 

 very useful in places at a distance from good natural sandstone, and 

 also of a method invented by Mr. Kuhhnann, of hardening soft stones 

 by infiltration with a solution of silica. 



15 (a). Glass itself is a kind of artificial stone. Its employment as 

 the principal part of the covering of a building, originated with the 

 great Exhibition of 1851. Its use for such purposes has been much 

 facilitated by the invention of processes for easily manufacturing it in 

 large flat sheets, 



16. Bituminous or Asphaltic Cements, wliich, though of organic origin, 

 are not organized, appear to have been used in Western and Central 

 Asia, in ages beyond the range of history. The most remai-kable use 

 which has been found for them in modern times, is the binding together 

 of the broken stone, gravel, sand, or other hard materials, with which 

 roadways are covered. This art has hitherto been brought to greater 

 perfection in France than in Britain ; but it is to be hoped that by 

 perseverance, we shall in time be enabled to equal or to excel our neigh- 

 bours. 



17. Amongst the Metals, the first place for abundance, for utility, 

 and for strength, belongs to Iron. The progress which has in recent 

 times been made in its production, has been in quantity rather than in 

 quality. In times, and by nations, that we consider barbarous, iron 

 and steel have been produced of a strength, toughness, and elasticity, 

 which we should find it difficult to equal. Our present superiority 

 consists mainly in the power of producing iron in abundance, sufficient 

 to meet any demand which its rapidly increasing use in every kind of 

 structure and machine may cause ; and the great improvements which, 

 in the course of the present century have taken place in the manufacture 

 of iron, have tended chiefly to increase the rapidity and diminish the 

 cost of its production. 



