722 PROCEEDINGS OF SECTION J 
3. The tensile strength, limit of elasticity, and ductility shall 
be determined from a standard test-piece, not less than one- 
quarter of an inch in thickness, cut from the full-size bar, and 
planed or turned parallel if the cross-section is reduced; the 
tangent between shoulders shall be at least twelve times its 
shortest dimension, and the area of minimum cross-section in 
either case shall not be less than one-quarter of a square inch, or 
more than one square inch. Whenever practicable, two opposite 
sides of the piece are to be left as they come from the rolls, but 
the finish of the opposite sides must be the same in this respect. 
A full-size bar, when not exceeding the above limitations, may be 
used as its own test-piece. In determining the ductility, the 
elongation shall be measured, after breaking, on an original length 
the nearest multiple of a quarter of an inch to ten times the 
shortest dimension of the test-piece (in which length must occur 
the curve of reduction from stretch on both sides of the point of 
fracture), but in no case on a shorter length than 5 inches. 
4, All iron to be used in the tensile members of open trusses, 
laterals, pins and bolts, except plate-iron over 8 inches wide and 
shaped iron, must show by the standard test-pieces a tensile 
strength in pounds per square inch of 
7000 x area of original bar 
52,000 — — (all in inches). 
circumference of original bar 
with an elastic limit not less than one-half the strength given by 
this formula and an elongation of 20 per cent. 
5, Plate-iron 24 inches wide and under, and more than 8 inches 
wide, must show by the standard test-pieces a tensile strength of 
48,000 pounds per square inch, with an elastic limit of not less 
than 26,000 pounds per square inch, and an elongation of not less 
than 12 per cent. All plates over 24 inches in width must have a 
tensile strength not less than 46,000 pounds per square inch, with 
an elastic limit of not less than 26,000 pounds per square inch. 
Plates from 24 inches to 36 inches in width must have an elonga- 
tion of not less than 10 per cent.; those from 36 inches to 48 
inches in width, 8 per cent.; over 48 inches in width, 5 per 
cent. 
6. All shaped iron, and other iron not hereinbefore specified, 
must show by the standard test-pieces a tensile strength in pounds 
per square inch of 
50,000 — 7000 x area of original bar 
circumference of original bar 
with an elastic limit of not less than one-half the strength given 
by this formula, and an elongation of 15 per cent. for bars five- 
eighths of an inch and less in thickness, and of 12 per cent. for 
bars of greater thickness. 
7. All plates, angles, &c., which are to be bent hot in the 
manufacture must, in addition to the above requirements, be 
