Mr. White on Calcareous Cements. 



53 



Third Experiment, made May 12, 1825. 



It having been suggested by Mr. Brunei, and Mr. Smirke, that it 

 would be useful to try the 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 

 April, in a vertical position, and of the following dimensions, viz., 

 six feet high, and about fourteen inches square. 



The First Pier (A) which was tried was of pure fresh Roman 

 cement, and was accident ly broken in laying down where the ce- 

 ment had partially set in the joint of brickwork before the adhesion 

 had taken place. A fragment of the pier, three feet six inches in 

 length, being laid down as here represented, 



A 



was carefully loaded at A with weights half a hundred at a time ; 

 it supported eleven hundred weight, and broke under eleven and a 

 half hundred weight. 



The Second Pier (B) was composed of three parts Pozzolano and 

 one part stone lime, reduced to putty as common mortar. This 

 pier was similarly placed in the supports, it broke in the middle, 

 and a fragment was similarly loaded, when it supported four hun- 

 dred weight, and broke under four and a half hundred weight. 



The Third Pier (C) three parts Pozzolano, and one part stone 

 lime, ground and fresh. This pier broke in turning it round, and 

 the fragment laid by, for further experiments. 



The Fourth Pier (D) three parts pure sharp sand, and one part 

 stone lime. This pier broke into three pieces on attempting to 

 lay it on the supports. 



The Fifth and Sixth Piers (E F) of three parts sharp washed 



