218 REPORT—1857. 
(3.) Resistance of eight-inch Tubes to Collapse. 
Diameter. Thickness, Length. Collapsing Pressure. 
ins. ins. ins. Ibs. per sq. in. 
(1.) Sih Stes oriole OAS, Yotie Bes Pt SOUS wei oe alt 32 
(2.) Sass. Mis. 6 Got ORB Si. ie. oe SU trey tes meye 39 
where from (1.) we have 
30 : 39:: 32 : e=41 lbs. 
differing from the result in (2.) by #oths. 
(4.) Resistance of ten-inch Tubes to Collapse. 
Diameter. Thickness. Length, Collapsing Pressure. 
ins. ins. ins. lbs. per sq. in. 
(1.) LU peReT aAeee 043 = OOsshe . «lsseuet is 19 
Oe eee Ne. | hens hy By att hoe 33° 
whence from (1.) we have 
30: 50:: 19: e=312 lbs. 
or 12 Ib. less than experiment (2.). In the same manner all the experiments 
might be taken and compared, and the law will be found to hold true in 
every case. The discrepancies are comparatively small, and, as they appear 
to follow no law, are evidently to be accounted for from defects in the con- 
struction of the tubes and difficulties in the mode of conducting the expe- 
riments, inseparable from such a mode of research. 
II. Strength as affected by Diameter.—A precisely similar law is found 
to hold in relation to the diameter. Tubes similar in other respects vary in 
strength inversely as their diameters. Testing this law in the same manner 
as the last, we may at once place the calculated pressure beside that derived 
from experiment. Hence we have the following table:— 
(1.) Resistance to Collapse of Tubes five feet long. 
Diameter. Collapsing Pressure. 
Ibs. per sq. in. 
ins. By Experiment. By Calculation. Variation. 
4. 3 Ibs. 
Grarsizergae she SAMARIA 3. xed 28°6 .. —3°4 
8 ZO OI. elles ALS. 2 Or Oe +07 
MOY (Fis. ares crate LGiORs teh}. 17°2 . 1:2 
Le ARoea reo ry AC Tra Meee .cyeie < L403) sere, eve 18 
The above variations are slight when compared with the resisting powers of 
the tubes. They were no doubt caused by the varying rigidity of the iron 
plates, or defects in the cylindrical form. Similarly we may take the results 
on tubes 30 inches long, and tabulate them in a similar manner. 
(2.) Resistance to Collapse of Tubes 2 feet 6 inches in length. 
Diameter. Collapsing Pressure. : 
Ibs. per sq. in. Variation. 
ins. By Experiment. By Calculation. Ibs. 
AG ras ofenoms crctecwe Se. erator he we PO es eee s Sete 
GME: <aMvodo tn 52 
Sits: thin win Sokn @ jn3D haved wees 0 
CO Se oie eS! le ness ete NOI Mee eee 2 
| el Bis oO ce 200) CRRA QGi odes’. EN See ee 
