52 Mr. White on Calcareous Cements, 



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First Experiment, tried August 9, 1 824.. 



A pier, three feet four inches wide, one foot ten and a half 

 inches thick, five feet eight inches high, was built on the 9th July, 

 1824, and was composed of hard sound London burnt stock- 

 bricks, and mortar of one part ground lime, one and a half parts 

 sand, and two parts rough Pozzolano. It was elevated by applying 

 screw-jacks on each side, course by course, beginning at fifteen 

 courses, or three feet nine inches from the bottom ; this elevation 

 from its foundation took place without any separation of the 

 courses until the screw-jacks were placed two courses, or six 

 inches from the top, when these two courses separated from the 

 remainder of the pier. 



The remainder of the pier was then thrown down, when it se- 

 parated at eight courses from the foundation, and exhibited that 

 the middle was not dry. 



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

 Mr. Mathew Wyatt, Mr. Smith, and many other gentlemen. 



Second Experiment, April 21, 1825. 



A pier of thirty-five courses of brickwork high, being six feet 

 wide, three feet thick, and eight feet ten inches in height, was built 

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

 cement composed of three parts British Pozzolano, ground and 

 sifted, having particles, none being bigger than one-eighth of an 

 inch, and one part of ground Dorking lime, unslacked, fresh mixed. 

 This pier was first elevated from its base by a strong chain, grap- 

 pling it at nine courses of brickwork from the top, again in the 

 same way at six courses from the top, and at last the whole pier 

 was suspended by a set of Lewis's, 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. 



