338 Mr. White's Design for the New London Bridge. 



Second trial, pier B. Pozzolano three parts, lime one 

 part. Section one hundred and eighty inches superficial. This 

 being overlaid with sand at top, the same escaped compres- 

 sion ; so that the result was uncertain. 



Third trial. Small fresh built pier nine inches square: 

 pozzolano three parts, ground lime one part. Compressed a 

 very little Avith 18,720llbs. ; entirely destroyed with 24<,480lbs. 

 Section eighty-one inches superficial. 



Fourth trial (G). Atkinson's Roman cement and sand, equal 

 measure. Cracked on two sides with 3,744 lbs. ; entirely de- 

 stroyed with 80,640 lbs. Section one hundred and ninety-six 

 inches superficial. 



Fifth trial (H). Pozzolano four parts, lime one part. 

 Cracked with 28,800lbs. ; fracture increased with 48,960 lbs. ; 

 entirely destroyed with 5 1,840 lbs. Section eighty-one inches 

 superficial. 



Sixth trial (C). Pozzolano three parts, Dorking lime one 

 part. Fractured one side with 31,680 lbs. ; fracture increased 

 with 43,200lbs. ; fracture again increased with 48,960lbs. 

 This experiment was not pursued until the pier was entirely 

 destroyed as in the preceding one. Section as the last. 



Seventh trial (D). Sand three parts, one part stone-lime 

 putty. Compressed on application of weights one-eighth of an 

 inch ; cracked with 40,320 lbs. ; fractured in five places with 

 46,080 lbs., which entirely destroyed it. Section as the last. 



Eighth trial. Pier of Portland-stone fourteen inches by 

 twelve inches, two feet seven inches high. A sudden fracture 

 was produced which divided the stones into two pieces in the 

 centre of the widest side, with one hundred and seventy-three 

 tons and a half; the upper end of the stone was bedded in poz- 

 zolano, which was compressed into a cake of five-eighths one- 

 fifteenth thick, in a wet state, which cake remained quite 

 solid after the fracture of the stone. 



These trials were made in the presence of Mr. Smirke, 

 Mr. Brunei, Lieutenant-General Sir A. Bryce, Mr. T. L. Do- 

 naldson, and many other gentlemen. 



Inferences from the foregoing Experiments. 



It may be inferred from the foregoing experiments, that an 

 important adhesion of brick-work had taken place by the use 

 of pozzolano, sand and lime, in the short period of thirty 

 days. 



That from the use of pozzolano and lime in the proportions 

 specified, almost all the advantages I'equired from a good 

 building cement were obtained. 



That Lord Mulgrave's or Atkinson's cement had, in the 



short 



