: 
ON STRENGTH AND PROPERTIES OF CASTIRON. 377 
On the Strength and other Properties of Cast Iron obtained 
from the Hot and Cold Blast. By W. Fairsarrn, Esq. 
Tue collecting of material for ascertaining the comparative 
values of iron, made from the hot and cold blast, has been a 
work of no small labour and expense. The chief difficulties 
arose from the greater part of the works in this country having 
only one sort of iron: large quantities of both sorts were ob- 
tained ; but, excepting those irons experimented upon, none 
could be found for comparison, nor any on which we could de- 
pend for analogous results. 
Nearly the whole of the Scotch irons are now prepared by 
the hot blast; and, with few exceptions, we may consider those 
of this country and Wales produced under circumstances pre- 
cisely similar. The great saving effected in the process of 
smelting by heated air, is in itself a sufficient inducement for 
its extended application; and in those districts where the iron 
is not deteriorated, there cannot exist a doubt as to the advan- 
tages derivable from its introduction. In confirmation of this opi-. 
nion, it may be important to know, that one-half or three-fourths 
of the British ores are now reduced by heated air. In the Staf- 
_ fordshire and Shropshire districts it has become almost univer- 
sal; and in North and South Wales the old process is rapidly 
giving way to the more economical application of the hot blast. 
_ In Yorkshire it has been tried with indifferent success, first at 
the Low Moor Iron Works, near Bradford, and more recently at 
the Milton Works, near Sheffield. The proprietors of the for- 
mer establishment persevered for some time in the use of the 
hot blast, but after repeated trials and experiments (part of 
which are briefly detailed in this Report), they abandoned the 
_ process, as injurious to the material, and reconstructed the old 
apparatus for the cold blast. 
I believe at the present moment they use air at the tempera- 
ture of the atmosphere: it is forced from the blowing cylinder 
into a dry receiver, and from thence into the furnace. Whether 
the failure which took place at the Low Moor was owing to 
some peculiarity in the ores, or from the presence of sulphur in 
the fuel, I am unable to determine. It is however obvious, that 
a considerable deterioration of strength was the consequence ; 
and from that cause, and that alone, I am informed, the hot 
blast was discontinued. 
At the Milton Works, the heated air is still in use; and al- 
