116 



Miscellaneous . 



[Feb. 



in suspension bridges, and those arising from internal pressure in cylinders, as in 

 guns, water-pipes, hydraulic presses, &c. but these fall rather under the head of 

 the resolution of forces than that of direct strength. It may just be observed, 

 that the equation due to the latter strain is 



t ( c — n ) = n R. 

 ■where t is the thickness of metal in inches, c the cohesive power in pounds of a 

 square inch rod of the given materials, n the pressure on a square inch of the 

 fluid in pounds, and R the interior radius of the cylinder in inches. Our column 

 marked C will apply to this case, but here again not more than one-third the 

 tabular value can be depended upon in practice. 



Table of the Mean Strength and Elasticity of various Materials, from the most 



accurate experiments. 



Names of Materials. 



WOODS. 



Ash, English, , 



Beech, ditto, 



Birch, ditto, 



Deal, Christina, 



Elm, English, 



Fir, Riga, 



Larch, Scotch, 



Oak, variable, «j , 



Poon, E. Indian, . . . 



Pine, pitch, 



Satin wood, B 



Saul, E. Indies, B. . 



Sisoo, ditto; B 



Teak, ditto, 



Ditto, ditto, B 



ft _ 



CO faC 



Cast iron, 



Iron. 



rom . 



C Mean 

 strength 

 ofcohesi- 

 on on an 

 inch sec- 

 tion, lbs. 



760 

 700 

 700 

 680 

 540 

 750 

 540 

 700 

 900 

 600 

 660 



1020 

 894 



1032 

 750 

 729 



17000 

 11500 



11000 



5780 



12600 



7000 



9000 



15000 



14000 



10500 



10866 



16351 



18500 



15000 



21957 



I w 



S. = 



4 bd 



Constants for 

 transverse 

 strain. 



E. =- 



Pw 



bd 



Constants for 

 deflection. 



7200 

 7760 



8100 

 9000 



69120000 

 91440000 



ffrc 



(.to 

 Malleable iron, . 



Iron wire, 



[Those marked B are extracted from Captain Baker's list in the 8th volume 

 of the Asiatic Researches, which contains a very full and valuable list of the 

 strength of Indian woods. — Ed.] 



16300 1 

 36000 J 

 60000 

 80000 



2026 

 1560 

 1900 

 1550 

 1030 

 1130 

 1120 

 1200 

 2260 

 2200 

 1630 

 2403 

 2290 

 2548 

 2460 

 1447 



6580000 

 5417000 

 6570000 

 6350000 

 2803000 

 5314000 

 4200000 

 3490000 

 7000000 

 6760000 

 5000000 

 6929108 

 8748000 

 7922716 

 9660000 

 6665142 



VI . — Miscellaneous. 



1. — Desiderata and Recommendations of the British Association for the Promotion 



of Science. 



In addition to the list of desiderata promulgated by the Association, on its 

 first meeting, which we re-published in the first volume of this Journal, page 

 308, the " Third Report," for 1833, contains several new suggestions and inqui- 

 ries, whence we hasten to extract such items as it may come within the power of 

 Indian scientific men to elucidate. 



In matters of scientific announcement, we are glad to perceive, that the Eng- 

 lish Government has undertaken the expense of reducing the observations of 

 Bradley, Maskeline, and Pond, on the sun, moon, and planets, at the suggestion 



