26 REPORT—1845. 
Years, ro) ° ° 
1806 Geneva. Reaum. +8°73 Fahr. 51°645 London 50°734 
1807 eA rr 7°78 » 49°505 x 48°367 
1808 ae ee 6°68 » 47°030 ae 48°633 
1809 > $5 7°54 » 48°965 ie 49°546 
1810 i es 8°57 ay DLEZB25 ee 49°507 
1811 af a 8°89 on 922 0025 33 51°190 
1812 ” ” 7°10 ” 47°975 2» 47°743 
1813 os ve 7°48 » 48°830 ys 49°762 
1814 Ja oa 7°34 » 48°515 ss 46°967 
1815 ‘s9 a 8°03 » §0°0675 a 49°630 
' 1816 ae ii 7°09 » 47°9525 eA 46°572 
1817 » 3 8°11 SAPP es 47°834 
1818 ae or 7°96 >», 49°910 ai 50°028 
1819 a ss 8°21 » 80°4725 oo 50°030 
1820 xs iy 7°63 » 49°1675 3 47°950 
1821 a a 8°28 2» §0°630 ee 49°810 
1822 ao aa 8°28 >», 50°630 ae 51°405 
1823 ” ” 6°50 rT} 46°625 ” 48°331 
+7:789 49°525 49°113 
Mean of first nine years,..... 7°790 49°161 
Mean of second nine years... 7°777 49°065 
On the Strength of Stone Columns. By Eaton Hovexinsoy, F.R.S. 
This paper contained the results of some experiments to determine the force ne- 
cessary to crush small columns of stone. The columns were of different heights, 
varying from 1 inch to 40 inches; they were square uniform prisms, the sides of 
the bases of which were 1 inch and 14 inch, and the crushing weight was applied 
in the direction of the strata. All the columns were cut out of the same block of 
stone, which was very uniform, and is of the strongest kind used for architectural 
purposes in the neighbourhood of Manchester. It is from the Peel Delph, Little- 
borough, Lancashire, on the confines of Yorkshire, The columns were cut, as near 
to the prescribed size as was practicable, by the mason, and were afterwards squared 
up with great care. They were crushed, by means of a powerful lever, between 
two flat surfaces of hardened steel, which from the nature of the apparatus were 
necessarily parallel. The apparatus was similar to that used in the author’s pre- 
vious experiments on the strength of pillars, and the only difference in these expe- 
riments from the preceding ones was, that a thin sheet of lead was placed over and 
under the specimen to equalize the pressure. 
From the experiments on the two series of pillars, it appears that there is a falling 
off in strength in all columns from the shortest to the longest; but that the dimi- 
nution is so small, when the height of the column is not greater than about 12 times 
the side of its square, that the strength may be considered as uniform; the mean 
being 10,000 lbs. per square inch or upwards. 
From the experiments on the columns 1 inch square, it appears that when the 
height is 15 times the side of the square, the aeronutle is slightly reduced; when the 
height is 24 tinies the base, the falling off is from 138 to 96 nearly; when it is 30 
times the base, the strength is reduced from 138 to 75; and when it is 40 times 
the base, the strength is reduced to 52, or to little more than one-third. These num- 
bers will be modified to some extent by the experiments in progress. 
In all columns shorter than 30 times the side of the square, fracture took place by 
one of the ends failing, showing the ends to be the weakest part; and the increased 
weakness of the longer columns over that of the shorter ones seemed to arise from 
the former being deflected more than the latter, and therefore exposing a smaller 
part of the ends to the crushing force. The cause of failure is the tendency of rigid 
materials to form wedges with sharp ends, these wedges splitting the body up in a 
manner which is always pretty nearly the same, Some attempts to explain this 
matter theoretically were made by Coulomb. As long columns always give way 
