ON STRENGTH AND PROPERTIES OF CAST IRON. 345 
FROM TABLE II.—COLD BLAST, 
| 
A A . Number | Mean crush- 
Diameter of cylinder in of expe. |Mean pmeb- ing weight per General mean per inch, 
parts of an inch. riments. |#98 Weight. | scuare inch. 
25 tS = Eee 
Ibs. Ibs. p 
6088 | 124,023 
14,190 | 128,478 
e 125,403 lbs. = 55 tons 193 
7 | 24,290 | 123,708 
2 
2 
3 
cwt. 
+ orfy Ble 
SS |e) 
2 
Equilateral triangle 
side “S66. 32,398 | 99,769 
Squares, 3 inch the mis 
| side. 24,538 | 98, ‘ih 
Rectangles, base 1:00 i allsee lbs. = 44 tons 183 
xX 243. 26,237 | 107,971 a 
Cylinders -45 inch di- | 
ameter and *75 high | 
(not in table). 2 | 15,369 96,634 | J 
The prisms, whose- bases were triangles, squares, rectan- 
gles, and the cylinders, last mentioned, were all cut out of the 
centre of a bar 1} inch square. 
It will be noticed that the cylinders in both the tables give 
much higher results per square inch than we have just found 
from the specimens cut out of the 14 inch bar. This the 
writer is inclined to attribute to no other cause but that they 
were mostly turned out of small cylinders cast for the purpose, 
which caused them to be harder than those from the middle 
of a larger mass. 
We will defer speaking of such comparative results as affect 
the general question of hot and cold blast iron, till all the evi- 
dence is obtained which the present paper will afford; drawing 
however, as we proceed, such other conclusions as seem to be 
made out from the experiments. 
Taking the mean crushing weight per square inch » as just ob- 
tained in the abstracts from the different cylinders in the Ist and 
énd tables, and retaining only the three first figures, we have 
From Ist table, diameter 43 253%, 32 Strength ) 131, 132, 118, 112. 
From 2nd _ do. aaiee ees og 124, 128, 124. 
The strengths per Square inch in each of these lines 
approach to an equality, particularly in the latter, where the 
areas of section vary as 1: 4; and the strength per inch is in 
_both cases represented by 124. In the former line the 
cylinders of 3 and 18 inch diameter give strengths varying as 
131 to 112 per square inch. The areas here vary nearly as 
1: 6°5, and the falling off in strength is about one-sixth. This 
ah diminution in the power of the larger cylinders to resist 
crushing, may be accounted for from those having been cut 
