172 ENQUIRY INTO THE STRENGTH AND 
ception of Tredgold, have, so far as I know, 
iiaade any inquiries into the fluidity of the dif- 
ferent sorts of cast irons; nor has much atten- 
tion been paid to their comparative powers of 
application. . 
The following pages contain—lIst., a laborious 
enquiry into the transverse strength of cast irons 
from various parts of the kingdom; and, 2ndly, 
an extended investigation into the less cultiva- 
ted field of their relative values, as regards their 
adaptation to the arts. 
In pursuing these experiments it was origin- 
ally my intention to have investigated the ques- 
tion of mixtures, or the proportions necessary 
for the production of different sorts of castings. 
This subject is, however, of such importance, 
and requires so much time and labour, that I 
am induced to forego its consideration for the 
present, and confine myself exclusively to the 
objects above stated. In adverting to this matter, 
however, it may be proper to remark that the 
same admixture or compound of pig iron is not 
suited for every description of casting ; a water 
wheel axle, or steam engine beam, for instance, 
requires a different mixture to the finer and sof- 
