___ eubes to have a strength per square inch of 6356, and MeV 
ona four ingh cube of Dartmoor granite, obtained 12,275 j 
16 Experiments on American and Foreign Building Stones. 
1. The one-inch cubes of alum limestone gave Mr. Dougherty — 
two thousand pounds, and the 4°75 inch cube, having 22°56 square — 
inches on the base, gave 5629 pounds per square inch. In com- — 
paring these with ‘the cube roots of the areas of base we have 
1: 4/22°56::2000 : 5652 or the calculated exceeds the experi- — 
mental result by only twenty three pounds, or 0:4 per cent. 
2. A two-inch cube of the alumstone in Dr. Page’s third — 
experiment gave per square inch of base 2281 pounds, and a 
33 inch cube in Mr. Dougherty’s third experiment, pores 3265 
pounds per square inch. Comparing these we have 1/4 : 4/1225 — 
72281 : 3312 showing that the calculated exceeds the experi- — 
mental result by 47 pounds or about one and a half per cent. 
3. The seventh Srreemment of Dr. Page gave 2625, and the — 
fourth of Mr. Dougherty gave 3765, consequently 4/ A: 9/1225 
2625 : 3812, in which the calculated exceeds the experimental — 
by | forty-two pounds, or 1,'; per cent. ; 
4. Mr. Dougherty’s first and second experiments on one inch ~ 
cubes gave 2000 pounds, and Dr. Page’s eleventh experiment on — 
two-inch cubes gave 2968. Hence 4/1: 4/4: 2000: 3156 
where calculation _—— experiment by two hundred and seven 
pounds, or 6-9 per c 
5. Comparing Dr. aa s eleventh experiment with Mr. Dougall 
. erty’s fifth, in which a block 43 inches on a side bore 5629 pounds — 
per square inch, we have 1/4 ; (/22°56: :2968 : 5283, in which — 
calculation falls short of experiment by 346 pounds or about 6 
per cent. 
, 6. Mr. Rennie’s eighth trial on marbles, showed that a one — 
inch cube of white Italian marble bore 3216, and M. Rondelet on — 
a two inch cube of the same, obtained per square inch, 4651 — 
pounds. Hence V1: W4::3216 : 5106, the calculated axicde 
ing the experimental result by 455 pounds, or nearly 9 per cent. 
7. By our reading of Mr. Rennie’s memoir, he obtained froma — 
two inch cube of Italian veined marble, 5445 pounds per square : 
‘inch, and Mr. Wyatt obtained from a 43 b y 4 inch block, ss 
pounds. Here, 74: */18::5445 : 8990 differing in defect from 
the experimental result by 261 pounds, or less than 3 per cent. 
8. If Mr. Rennie’s experiment on Aberdeen granite was, ne 
we suppose, also on a two inch cube, its strength per square inch — 
was 6139 pounds, and as Mr. Wyatt obtained from Aberdeen — 
granite, when tried in blocks 44 x 4 inches on the base, a strength © 
of 10,393 pounds, we have 4: */18::6139 ; 10-130 where 
the calculated falls short of the experimental result by 263 ee 
per cent. 
“9. Mr. Rennie proved Cornish granite in one anda 
