OF ARTS AND SCIENCES : FEBRUARY 14, 1865. 



409 



Table I. gives the dimensions and the breaking weights by formula 

 (1) and by experiment of several long, hollow pillars with flat ends, 

 made of Low Moor iron, No. 2. It will be seen that the breaking 

 weights by experiment vary from about eighteen per cent greater to 

 about one per cent less than the computed breaking weights, the mean 

 being about eight per cent greater. 



Table II. gives the dimensions and breaking weights of solid pillars 

 with flat ends, cast from several kinds of iron made in Great Britain ; 

 also the breaking weights of the same pillars, computed by formula (1). 

 It will be observed that the breaking weights by experiment vary from 

 about thirty per cent greater to about fifteen per cent less than the 

 breaking weights computed by the formula, the mean being about nine 

 per cent greater. 



Table II. 



Desisrniition of the 



Expt'riuients iu 



lloi-lgkinson's 



Tables. 



Tab.II.Ex.il 



" 12 



" 13 



" 14 



Tab. III. Ex. 1 

 .< << 2 



" 3 

 <( << ^ 



" " 5 

 " 6 



" " 8 

 " 9 

 " 10 

 "11 



" "12 



" 13 

 " 14 



" " 15 



" 16 

 " 17 



" " 18 

 " 19 



" " 20 

 " 21 



it ti o9 



(( tt QQ 



" 24 



Description of the iron from which 

 the pillars were cast. 



Low Moor, No. 2 



ii n 



Blaenavon, No. 3 



Old Park, No. I 



Derwent, No. 1 

 (( ii 



Portland, No. 1 

 << <( 



Calder, No. 1 



1st London Mixture, ^ old iron 



it a 



Level, No. 1 



i( it 



Coltness, No. 1 

 (( it 



Carron, No. 1 

 <i tt 



Blaenavon, No. 1 



it n, 



Old Hill, No 1 

 tt (( 



2d London Mixture, | old iron 



Diam- 

 eter. 



In. 

 2.553 

 2. .539 

 2.556 

 2.. 54 6 

 2.503 

 2.526 

 2.529 

 2.517 

 2.493 

 2.527 

 2.490 

 2.519 

 2.533 

 2.548 

 2.518 

 2.501 

 2.516 

 2.496 

 2.506 

 2.510 

 2.487 

 2.499 

 2.520 

 2.523 

 2.511 

 2.496 

 1.530 

 1..541 



to 

 a 



Ft. 

 10.00 

 10.00 

 10.00 

 10.00 



Break- 

 ing 

 weight 

 by for- 

 mula 

 CD- 



Lbs. 

 55,215 

 54,148 

 55.446 

 54,680 



Break- 

 ing 

 weight 

 by ex- 

 peri- 

 ment. 



10.00 51,471 

 10.00 53,170 

 10.00;.')3,394 

 10.00|52,500 

 10.00 50,745 

 10.00:53,245 

 10.00 50,528 

 10.00 52,649 



10.00 

 10.00 

 10.00 



53,695 

 54,832 

 52,575 



10.00 51,325 



10.00j52,426 



10.00,50,962 



10.00 51,69 



10.00 



10.00 



10.00 



10.00 



10.00 



10.00 



10.00 



10.00 



10.00 



51,984 

 50,313 

 51,180 

 52,723 

 52,946 

 52,058 

 50,962 

 8,968 

 9,199 



Lhs. 

 55,973 

 55,973 

 56,914 

 57,855 

 66,792 

 65,381 

 57,855 

 66,733 

 59,736 

 62,559 

 60,677 

 60,677 

 54,562 

 59,266 

 54,091 

 56,443 

 56,443 

 48,917 

 52,210 

 53,151 

 48,917 

 49,858 

 44,683 

 45,154 

 63,499 

 58,325 

 11,204 

 10,868 



Propor- 

 tional 

 difference. 



+0.0137 

 +0.0337 

 +0.0265 

 +0.0581 

 +0.2977 

 +0.2297 

 +0.0835 

 +0.2711 

 +0.1772 

 +0.1749 

 +0.2009 

 +0.1525 

 +0.0161 

 +0.0809 

 +0.0288 

 +0.0997 

 +0.0766 

 —0.0401 

 +0 0100 

 +0.0224 

 —0.0277 

 —0.0258 

 ■0.1525 

 ■0.1472 

 +0.2198 

 +0.1445 

 -1-0.2493 

 +0.1814 



Mean proportional difference 



+0.0877 



Table III. gives the results of experiments on solid pillars, cut out of 

 the fragments of the pillars, 10 feet long, used in previous experiment,^!, 



In the last six ex- 



the results of which are given in Tables I. and II. 



