on the Principle of Cementitious. Architecture. 335 



Second Experiment, tried 2lst of April, 1825.— A pier of 

 thirty-five courses of brick- work high, being six feet wide, three 

 feet thick, and eight feet ten inches in height, was built also 

 9th of July 1824, of hard sound London stock bricks, and of 

 a cement composed of three parts British pozzolano, ground 

 and sifted, having no particles bigger than one-eighth of 

 an inch, and one part of ground Dorking lime, unslaked, 

 fresh mixed. This pier was first elevated irom its base by a 

 strong chain, grappling it at nine courses of brick-work from 

 the top ; again, in the same way, at six courses from the top ; 

 antl at last the whole pier was suspended by a set of lewises, let 

 into the middle of the top of the pier, about fifteen inches 

 deep ; the weight of the pier was about nine tons. 



This experiment was tried in the presence of Mr. Brunei, 

 Sir Thomas Baring, Admiral Sir Edward Codrington, Colonel 

 Lowther, Mr. Smirke, Dr. Chumside, and nearly two hundred 

 spectators. 



Third Experiment, made \2th of May, 1825. — It having 

 been suggested by Mr. Brunei and Mr. Smirke, that it would 

 be useful to try ihe comparative adhesive properties of these 

 cements by building other piers of such dimensions as might 

 enable them to be laid horizontally, and have weights placed 

 on them in the middle, — nine piers were constructed on the 

 21st and 23rd of April, in a vertical position, and of the fol- 

 lowing dimensions ; namely, six feet high, and about fourteen 

 inches square. 



The cement of the first pier (A) which was tried was of pure 

 fresh Roman cement, and was accidentally broken in laying 

 down, at a place where the cement had partially set in the joint 

 of brick-work, before the adhesion had taken place. A frag- 

 ment of the pier, three feet six inches in length, being laid 

 down as here represented, 



A 



30 inches. 



■IL 



was carefully loaded at A with weights, a half-hundred at a 

 time; it supported eleven hundredweight, and broke under 

 eleven hundred weight and a half 



The cement of the second pier (B) was composed of three 

 parts pozzolano, and one part stone-lime, reduced to putty as 

 conniion morlar. This pier was similarly placed in the suji- 

 ports ; it broke in the middle ; and a fragment was similarly 



loaded, 



