234 
MINUTES OF PROCEEDINGS OF 
mean is generally found either in a mixture of white and grey cold blast* 
irons in proportions which will vary slightly according to the size of the 
projectiles and the brand of the iron, or in the employment wholly of 
“ mottled" iron—an iron which falls about mid-way as regards its chemical 
characteristics, between white and grey iron, containing about half its carbon 
in a combined, and the other half in an uncombined state; and which may, 
in fact, be regarded as white and grey iron ready mixed.* Purther than this 
it is unnecessary, indeed, it would be difficult and perhaps undesirable, to 
detail the precise mixtures or natures of iron employed by Major Palliser 
for his projectiles. Suffice it to say that while these mixtures or natures are 
now carefully selected with reference to the particular object in view, and 
by the light of the experiments above referred to, no such selection was ever 
made in the case of shot cast in chill, when ordinary grey or the cheapest 
available irons were commonly employed. 
It follows, then, from what has been stated, that neither in their origin, 
in their object, or in their nature did the shot cast in chill of half a century 
ago resemble the chilled shot proposed and perfected by Major Palliser, 
whose claim to originality in the production of a shot of superior penetra¬ 
tive powers may therefore be fully conceded. 
Nor do Major PallisePs claims to originality in the production of these 
projectiles cease here. A reference to the passage above quoted, in which he 
describes the origin of his chilled shot, will shew that the problem which he 
set himself to solve was two-fold :—1st, to produce a shot of great hardness, 
as compared with ordinary cast or wrought-iron, and 2nd, a to make the 
fore part of the shot of such a form as would convert the sudden shock of 
impact as much as possible into a uniformly increasing pressure, when the 
brittle nature of the material would not be of much consequence." In other 
words, the form of the shot must be such as to neutralize the inevitable 
brittleness of the material. The form of head of chilled shot is therefore a 
matter of scarcely less importance than the iron of which it is composed. 
No subject has probably provoked more discussion than this one, of the 
form of head best suited for penetrative purposes, and on no subject have 
more opposite opinions from time to time been advocated and received. Por 
some time a flat-headed shot was thought to be the most serviceable, and 
this view was strongly advocated by Mr Whitworth. The experiments 
* Cold blast irons have been used, not merely because they generally take tbe chills better than 
hot blast irons, but because their superior strength seems to render them more suitable for the 
purpose. There are, however, grounds for hoping that certain brands of hot blast irons, or of old 
iron, in the form of condemned stores, &c., may be usefully employed to a considerable extent. This 
will effect a material cheapening in the manufacture, and be an important point in favour of the 
projectiles. 
f The following analysis of samples of grey, mottled, and white irons exhibit very clearly the 
conditions and quantities of carbon contained in each nature : 
Combined carbon p.c. Uncombined carbon p.c. (graphite.) 
Grey 
1-02 
2-64 
Mottled ... 
1-79 
1-11 
White 
2-46 
0-87 
For these analyses, together with some other information embodied in this paper, I am indebted 
to a lecture delivered by Mr Bloxam, Professor of Chemistry, in 1865, to the “ Advanced Class” 
of Artillery Officers. 
