476 
ME. W. H. BAELOW ON THE EESISTANCE OP PLEXTEE 
ing from the experiments on the tensile strength of the metal, as derived from each form 
of section, the deduced values off will be as follows : — 
No. 
1. 
No. 
2. 
No. 
3. 
No. 
4. 
No. 
5. 
No. 
6. 
No. 
7. 
No. 
8. 
No. 
9. 
No. 
10. 
No. 
11. 
No. 
12. 
No. 
13. 
No. 
14. 
No. 
15. 
No. 
16. 
The results 
Solid rectangle 
Form of Girder. 
/=17,971 
Open girder y=17,582 
Open girder /*= 17,442 
Open girder y=17,882 
Open girder y=19,058 
Open girder ^’=18,070 
Open girder y=19,659 
Square bar, 1 inch, section broken on its side . . . y’=19,399 
Round bar, 1 inch, section ^”=20,236 
Square bar, 1 inch, section broken on its angle . . . ^’=19,213 
Square bar, 4 inches, section broken on its side . . . ^=16,644 
Round bar, 2^ inches diameter ^=15,902 
Round bar, 2^ inches diameter y= 17,7 7 8 
Square bar, 4 inches, sectional area broken on its angle y‘= 16,878 
Compound section, flanges horizontal ^=20,942 
Compound section, flanges vertical ^=18,460 
The results thus obtained, though not perfectly regular, are 'udthin the limi ts of the 
variation exhibited by the metal, as shown by the experiments on direct tension given 
in the former paper. 
If the results be classifled, — 
The mean tensile strength, as obtained from the open gii’ders, Experiments] 
Nos. 2 , 3, 4, 5, 6 and 7, is J 
From the solid bar. No. 1 17971 
From the inch bars, square, round, and square bars broken diagonally, Nos. ^0 ^ 90^5 
9 and 10 J 
From the bars of 4 inches sectional area, square, round, and square ^^’*0 ]^ 0 g()Q 
broken diagonally. Nos. 11, 12, 13, and 14 J 
From the compound sections, in which the metal was half an inch thick . . 19701 
The variation in strength, as exhibited between the small and the lai’ge bars, is in 
accordance with the experiments made by Lieut.-Colonel James, and recorded in the 
‘ Report of the Commissioners upon the Application of Iron to Railway Structures.’ 
The results obtained in all these varieties of form of section being so fai' satisfactory, 
it appeared desirable to test the application of the formulae to other known experiments, 
of which the following may be given as examples : — 
