314 THE USES OF ARTIFICIAL STONE. 



SCIENTIFIC MISCELLANY. r 



THE USES OF ARTIFICIAL STONE. 



BY HENRY REED, C. E. 



Building with concrete materials has been practiced in every age ; but the 

 Romans gave the greatest consideration to the subject and they constructed sub- 

 aqueous works by that system thousands of years ago. Their name for a mixture 

 of hydraulic mortar and broken stones was signinum, and with that preparation 

 they constructed various piers and harbors on the shores of the Mediterranean 

 Sea. Subsequently they added pozzuolana, which imparted increased setting 

 energy to the comparatively inert lime, with the advantage of improved hydraul- 

 icity. French engineers in modern times adopted a similar system; but in 

 England, from a variety of causes, the matter has not received that attention 

 which its importance deserves. 



A difference of opinion exists as to the difference between beton and concrete ; 

 and some writers endeavor to draw a distinction between the two, regarding beton 

 as being made with hydraulic mortar and concrete prepared from non-hydraulic 

 limes. Others again consider the difference to be in the mode of mixture ; when 

 the cement or lime is first mixed with sand, before being incorporated with gravel, 

 it is termed beton, and when that preliminary operation is omitted it is called con- 

 crete. Such distinctions are too nice for practical purposes, and are alluded to 

 only for the purpose of avoiding confusion in the use of the two terms. The 

 names beton and concrete may therefore be considered synonomous, as indeed 

 their names imply ; and we may regard the term concrete as generic, embracing 

 all mixtures of whatever description used for building purposes. English cob, 

 Irish dab, and their several varieties, as well as Spanish tapia and Italian ptsa, 

 may be termed concrete, for they are respectively amalgamations of several ma- 

 terials. 



General Pasley has assigned the merit of introducing concrete in England to 

 Sir Robert Smirke, who used it on an extensive scale in the foundations of Mill- 

 bank Penitentiary ; and in his work on cements relates the accidental circum- 

 stances which led that eminent architect to the adoption of the preparation. It is 

 immaterial to us who was the inventor or adapter of one kind or other of the dif- 

 ferent varieties of concrete, although we may be justified in ascribing it to an ori- 

 gin of great antiquity. The use of conglomorate masses of clay only, or in com- 

 bination with other materials, continued through many ages of the world's history 

 until the discovery of iron working, when man was enabled by its agency to adapt 

 and shape stone to the required forms. Subsequent chemical knowledge led to 

 the use of cementitious materials for connecting or binding stones ; and clay, bit- 

 umen, sulphates and carbonates of limes, and pozzuolanas were severally used for 



