THE KOYAL ARTILLERY INSTITUTION. 
193 
Prior to the advent of rifled guns, it had been frequently proposed 
in Prussia to employ a lighter and stronger metal than bronze for field 
guns, in order to increase their mobility. Between 1844 and 1855 
several steel S.B. field pieces were manufactured for trial, both at 
Bochum and also by Messrs. Krupp, at Essen, and on account of the 
good results given by these guns, an experimental committee actually 
prepared designs in 1857 for a service S.B steel gun of 12 centimetre 
calibre, and to fire charges of between 3J and 4^ lbs. 
When therefore it became evident that rifled guns must take the 
place of smooth-bores and that a new armament had to be provided, 
Prussia was naturally ready to adopt for that armament a metal which 
had been proved, even for the old guns, to be better than bronze. 
The enterprising firm of Krupp completed in 1856 a 9c (3*2-inch) rifled 
steel gun, according to the designs of an artillery committee, which 
was so satisfactory, that in 1859 steel was definitely adopted by the 
Prussian authorities as the material to be used for the new field guns. 
For the sake of economy, attempts were at the same time made to 
utilize the existing 12c and 9c S.B. bronze guns by rifling them; these 
attempts failed and in 1865, all the rifled Prussian field pieces— 9c and 
8c guns—were made of steel, while the 12c S.B. of bronze were 
also retained, the latter piece was the Horse Artillery Gfun employed 
by Prussia in the campaign of 1866. 
In England bronze was not considered of adequate strength, and the 
distinguished engineer, Sir W. Armstrong, having constructed a rifled 
gun of wrought iron as early as 1854, and having matured a satisfactory 
method of manufacture, his system was adopted to satisfy the imminent 
necessity that existed for an immediate supply of rifled field pieces. His 
first guns were made entirely of wrought iron, but many of the later 
Armstrong field guns have steel barrels. To these two metals iron and 
steel we have steadily adhered in the manufacture of our field ordnance 
with the partial exception mentioned further on. 
With S.B. bronze guns much inconvenience was occasioned by the 
softness of that alloy, especially when heated by rapid firing,* and as 
experience was gained concerning rifled ordnance in the field, it was 
found that the defects inherent to ordinary bronze were still more 
serious in such pieces. Their accuracy was affected by much firing, 
and the greater pressure in the powder chamber quickly developed 
flaws by burning out the tin spots.f The cutting of the grooves also 
laid bare many of these spots, which otherwise would not have been 
apparent. 
* in Lis “ Employment of Artillery/’ Sir John May tells ns that in the first siege of 
Baclajos by onr forces in 1811, we had to borrow from the Portngnese a siege train of 
bronze ordnance. The rapid firing of these pieces soon disabled 18 ont of 40 guns, and the 
siege was consequently raised. Shortly afterwards, in 1812, we again attacked that 
fortress, but with an English siege train of iron ordnance, when it soon fell into our hands. 
f “ Tin spots,” so called, being patches or veins of white alloy, rich in tin, always 
found in ordinary bronze. Such patches are burnt away with a comparatively small 
amount of heat, they are harder than bronze. 
