On the Resistance of Solids, A27 
TABLE IV.—MISCELLANEOUS SUBSTANCES. 
Ae BHETOS 7 
BE-|S2S] os 
See wlan <2 ee 
Substances. zg z 2 g a 3 4< Authority. 
So/£$2) 25 1 
R3Z0)225/ FH 
o=7 8 
Hemp fibres re : iF 
phrcdl sovedher 9 766 | 92,000 Rumford, Phil. Mag. x- 
Paper strips a ‘ 
eaaed cout 3*184 | 30,000 Idem. : 
ayery erie 1°765 | 16,626 Muschenb. Intro. ad Phil. Nat, i, 463. 
ate, Welsh, é : Whe 
(clay slate) +f 1-358 ] 12,800 By my trials, 
Plate-glass _.... t}1-000 | 9,420 2-455 | By my trials. 
Marble (white) $/0°955 | 9,000 Robison, Gregory’s Mech, i. 129. 
Horn of an ox ....10°950 | 8,949 Muschenb. Intro. ad Phil. Nat. i, 463. 
Bibpisbone Pens 0-814 | 7,667 Idem, 
oue ofan ox ....10:559 | 5,265 Idem. 
Hard stone+ of -| g*aRM ns f 
ra ee : ; 0-230 | 2,166} 2°357 | Gauthey,Roz.Journ.dePhysiq.iv.413. 
Portland stone, 
at lime- > | 0:083 184 By my trials. 
stone + 
7.2 .0/0''s' 8 + 
Soft stone * of : 
Bimaosh ty: . t \ 0-041 385) 2 071 | Gauthey,Roz.Journ.dePhysiq. iv.313. 
Brick from ...... 0-031 300 t Coulomb, Young’s Nat. Phil. ii. 174. 
iy eee 0-030 2980 A * 
eeu fron) Dou ; fae By my trial,—colour deep-brick red, 
a NN , 0 029 275 ; brittle. 
Stone,homogene- 
ae white, of a ¢ |0-022 207 Coulomb, Gzavres de Gauthey, i. 277. 
ine grain.... 
Plaster of Paris...|0-0077| 72 Rondelet, L?Art de Batir, i. 314, 
Mortar of sand 
and lime, 16 
years made .. 
00054 50 Idem. 
In our inquiries respecting the laws which regulate the phe- 
nomena of nature, we must always exclude certain circumstances 
which are not necessary, nor do not always accompany the phe- 
nomena. 
This principle of exclusion is one of the most prominent fea- 
» 
+ This stone was hard, of a red colour, and the beds distinctly marked. 
% This stone was white, rather soft, and the beds not distinctly marked, These 
numbers were calculated from experiments on the transverse strength, because 
the experiments which Gauthey made on the suspending strength are so extremely 
irregular. He appears to have been aware of the principal cause, whioh was owing 
to his mode of fixing the pieces. ‘Ihe results of Gauthey’s experiments on the 
suspending strength of stones have been, by mistake, copied as experiments on 
crushing, by Professor Robison, in his article Strength of Materials, Encyclo. Brit. 
See 4th edition, p.'159. This mistake has been copied by some other writers 
from the article above mentioned, and among others by the writer of the article 
Strength, Rees’s Cyclopedia. 
Gauthey’s experiments on crushing are much more numerous and regular. 
See Rozier’s Journal de Physique, iv, 406. 
tures 
