80 
(1) I find it a matter of general opinion that pig-iron 
breaks much more easily in frost than in ordinary tempera- 
tures, and that breakages of castings are much more 
frequent in frosty weather. 
(2) In rolling mills, and particularly where chilled rolls 
are employed, especial care has to be used in frosty weather 
to warm the rolls before using them, and when in use to 
keep them carefully covered from the frosty air. If not 
properly protected and carefully managed they are found 
to be very liable to fracture. 
(3) Mr. Edgar Gilkes, of Middlesborough, informs me that 
the cast iron wheels of the Chaldron wagons of the Stockton 
and Darlington railway are found to fracture very fre- 
quently in frosty weather, and in a severe frost it is some- 
times quite a serious matter. 
(4) Messrs. Peel, Williams, and Peel had a remarkable 
example on January 5th (20° F.). A hydraulic cylinder 
had been cast upon a cast iron hollow core bar 7 inches in 
diameter and 1£ inches thick, coated with lb inches of loam 
and hay. It was put out in the yard to cool during the 
severe frost, and when they came to draw the core bar it 
broke by the mere torsion, and was found to be quite brittle. 
A portion of this core bar was warmed, and it was then 
found to have recovered its nature and to be quite strong 
and tough. The lowest temperature on this date was 
19° Fahrenheit, and the casting was expossd to it for many 
hours. Numerous other examples could be readily fur- 
nished if required. 
There can therefore be no doubt whatever that the 
strength of cast iron is very materially lessened by severe 
cold. 
For experiments in wrought iron I am indebted to many 
friends, and the results are of similar import. My first ex- 
periments were directed to the method adopted by Mr. 
Kirkaldy, and I soon found that neither by torsion nor 
