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MINUTES OF PROCEEDINGS OF 
We have thus in connexion with chill-casting, these data: 1st, That 
white iron contains its carbon chiefly in a combined state; 2nd, That iron 
so constituted is intensely hard as compared with grey iron, in which the 
carbon exists chiefly as graphite; 3rd, That rapid solidification, such as 
chill-casting, cc favours the retention of carbon in the combined state,” and 
thus tends to harden and alter the character of the iron. 
The process of chill-casting is and has long been perfectly well known in 
the iron trade, being usefully employed for many purposes, such, for 
example, as the surface-hardening of those portions of machines or articles 
in which great hardness is required.* Moreover, owing to certain mechani¬ 
cal advantages which the process is sometimes found to possess, and to the 
comparative cheapness with which by means of it certain articles can be 
produced, it is frequently employed where surface hardness is not specially 
sought for — te as, for example, with railway chairs, when large numbers are 
to be produced of identical dimensions.”t For similar reasons shot were so 
cast for many years, J and to this day, although the necessity for the distinc¬ 
tion has long passed away, the nomenclature of “ shot cast in sand,” or 
ef sand shot,” is retained for those small round shot used for making up 
case and grape, which were alone cast in sand moulds at a time when the 
higher natures were cast in chills. 
But here it is necessary emphatically to explain that the shot cast in chills 
of that period were very different projectiles from the chilled shot of the 
present day. It is important clearly and thoroughly to grasp the distinction, 
first, because such a distinction involves the recognition of Major Palliser’s 
claim to originality in the production of a particular projectile for penetra¬ 
tive purposes ; and, secondly, because it is difficult otherwise to appreciate the 
characteristic construction of this particular projectile. 
The shot cast in chills were, as we have seen, so cast for manufacturing 
reasons only , and without reference to the qualities or intended uses of the 
projectiles thus produced. The origin of the chilled shot, on the other 
hand, Major Palliser tells us, was as follows :—“ At the time I first heard 
of Mr Whitworth's tempered steel shot, I conjectured that the results 
he obtained were to be attributed as much to the hardness, as to the 
toughness and tenacity of the material he employed. I had previously 
noticed in some experiments that I had made in casting iron round wrought 
iron tubes, that, under certain conditions, the cast-iron was rendered very 
hard and unyielding where it came into contact with the cold wrought-iron. 
I was aware that cast-iron would resist a far greater crushing force than 
wrought-iron could, and putting these facts together, I thought it highly 
probable that if I cast an iron shot in a mould which would rapidly carry 
off the heat by conduction, and if, at the same time, I made the fore part 
of the shot of such a form as would convert the sudden shock of impact 
* “ All sorts of articles in which hardness of surface was a desideratum, have been cast in chills 
for years, if not centuries. The Messrs Ransome turn out hundreds of tons of chilled ploughshares 
annually .”—Mechanics Magazine , August 26th, 1864. 
f Letter of Mr Alexander to Mechanics’ Magazine, July, 1864. 
J During the great French war, at the close of the last, and the beginning of the present cen¬ 
tury, the system of chill-casting shot prevailed in England. Before that, sand and sand loam had 
been used. Subsequently sand was reverted to. 
