ON STRENGTH AND PROPERTIES OF CAST IRON, 349 
equal to that of the two opposing or double wedges, then these 
cones and wedges could not be isosceles after fracture com- 
menced. It is shown by several of the figures (figs. 4, 6, bd, 
13, 20, &c.) how fracture takes place, and that in such eases 
the wedges do not meet directly and crush their opponents, 
but have sharp points and slip past each other to effect the 
destruction of the piece of which they are formed. It is evi- 
dent therefore that the angles, which the sides of these wedges 
make with their base, cannot in this case be equal; this is 
shown by the rectangles one inch high, and it was found to 
exist in a higher degree in the fracture of those of half the 
height. In these the angle with the base was further reduced, 
through an almost necessary tendency of the specimen to divide 
itself in the diagonal; though the angle there was less, on 
account of the compression of the prism, than the natural 
angle in this material. The angle of the wedge as obtained 
from different specimens is as follows : 
Cylinders. 
. DO FAO 1 OTFl pfgo I , 
oe, No. 2, 54 fon 1, 10’, Mean 55° 11! 
Bae, es Nee os". iy 56°, 58°, 56°, Do. 57° 8! 
Coed-Talon, No. 2, 55°, 56°, 56°, 531°, 53°, 49° Do. 53° 40! 
Mean angles from cones 562°, 542°, 571° - Do. 56° 10! 
Mean from the whole, being 21 cylinders of various) - 5° gal 
lengths. ° : : : : - Nn ee 
Rectangular prisms 1 inch high, Carron Iron, No. 3, angles 
made by the sides of the double wedge, with the base. 
Cold Blast 54° 
58 
1 ae 
aot Blast By by ti h, 53° SMean 56° 43! 
5410 
60 
Rectangular prisms } inch high, Carron Iron, 
48°, 51°, 52°, 54°, 57°, 52°, - Mean 52° 40/ 
Mean angle from the above rectangular prisms . 54° 41! 
Prisms, Base +50 x °50 inch. 
Carron Iron, No.2. . . 53°, 54° » Mean 53° 30! 
