which weighs about 13 tons, is formed of an inner lining of
wrought iron longitudinal bars arranged like the staves of a
cask and welded together, surrounded by rings of wrought iron
driven or shrunk on. The chamber portion is of smaller diameter,
and some suppose it to be screwed to the muzzle portion.
The length of the gun is 197 in., the diameter of the bore 25 in.,
and the chamber 10 in. at the front and tapering to 6 in. diameter
at the breech end. It fired a granite ball weighing about
700 ℔. Two wrought iron guns left by the English in 1423 when
they had to raise the siege of Mont St Michel in Normandy belong
to about the same period; the larger of these guns has a bore of
19 in. diameter.
“Mons Meg”
(fig. 2) in Edinburgh
Castle is a
wrought iron gun
of a little later
period; it is built up in the same manner of iron bars and
external rings. It has a calibre of 20 in. and fired a granite
shot weighing 330 ℔.
Fig. 2.— Mons Meg.
Bronze guns of almost identical dimensions to the “Dulle Griete” were cast a little later (1468) at Constantinople (see Lefroy, Proc. R. A. I., vol. vi.). One of these is now in the Royal Military Repository, Woolwich. It is in two pieces screwed together: the front portion has a calibre of 25 in. and is for the reception of the stone shot, which weighed 672 ℔; and a rear portion, forming the powder chamber, of 10 in. diameter. The whole gun weighs nearly 1834 tons.
To give some idea of the power of these guns, the damage done by them to Sir John Duckworth’s squadron in 1807 when the Dardanelles were forced may be instanced. In this engagement six men-of-war were more or less damaged and some 126 men were killed or wounded. The guns were too unwieldy to lay for each round and were consequently placed in a permanent position; they were often kept loaded for months.
The 16th century was remarkable from the fact that the large bombard type was discarded and smaller wrought iron guns were made. This was due to the use of iron projectiles, which enabled a blow to be delivered from a comparatively small gun as destructive as that from the very weighty bombards throwing stone shot.
Bronze guns also now came into great favour. They were first cast in England in 1521 (Henry VIII.), and iron cannon about 1540, foreign founders being introduced for the purpose of teaching the English the art. The “Mary Rose,” which sank off Spithead in 1545, had on board both breech-loading wrought-iron and muzzle-loading bronze guns.
The smaller guns cast at this period were of considerable length, probably on account of the large charges of meal powder which were fired. The long bronze gun in Dover Castle known as “Queen Elizabeth’s pocket pistol” has a calibre of 4·75 in.; its bore is 23 ft. 1 in. long or 58 calibres, but its total length including the cascable is 24 ft. 6 in. It was cast at Utrecht in 1544 and presented by Charles V. to Henry VIII.
Little or no classification of the various types of guns was attempted during the 15th century. The following century saw some attempt made at uniformity and the division of the several calibres into classes, but it was not until about 1739, when Maritz of Geneva introduced the boring of guns from the solid, that actual uniformity of calibre was attained, as up to this date they were always cast hollow and discrepancies naturally occurred. In France organization was attempted in 1732 by Vallière, but to Gribeauvai (q.v.) is due the credit of having simplified artillery and introduced great improvements in the equipment.
It is not possible to compare properly the power of the earlier guns; at first small and feeble, they became later large and unwieldy, but still feeble. The gunpowder called “serpentine” often compounded from separate ingredients on the spot at the time of loading, burnt slowly without strength and naturally varied from round to round. The more fiercely burning granulated or corned powder, introduced into Germany about 1429, and into England shortly after, was too strong for the larger pieces of that date, and could be used only for small firearms for more than a century after. These small guns were often loaded with a lead or lead-coated ball driven down the bore by hammering.
The bronze and cast iron ordnance which followed in the 16th century were strengthened in the 17th century, and so were more adapted to use the corned powder. By this means some access of energy and greater effective ranges were obtained.
In the 18th century and in the first half of the 19th no change of importance was made. Greater purity of the ingredients and better methods of manufacture had improved gunpowder; the windage between the shot and the bore had also been reduced, and guns had been strengthened to meet this progress, but the principles of construction remained unaltered until the middle of the 19th century. Metallurgical science had made great progress, but cast iron was still the only metal considered suitable for large guns, whilst bronze was used for field guns. Many accidents, due to defects developing during practice, had, however, occurred, in order to prevent which experimental guns constructed of stronger material such as forged iron and steel had been made. Some of these weapons were merely massive solid blocks, with a hole bored in for the bore, and only withstood a few rounds before bursting. This result was attributed to the metal being of an indifferent quality—quite a possible reason as the treatment of large masses of steel was then in its infancy, and even with the best modern appliances difficulties have always existed in the efficient welding of large forgings of iron. Forged iron, however, always gave some evidence of its impending failure whereas the steel burst in pieces suddenly; steel was, therefore, considered too treacherous a material for use in ordnance. This view held for many years, and steel was only again employed after many trials had been made to demonstrate its reliability. It will be seen later that the ill success of these experiments was greatly due to a want of knowledge of the correct principles of gun construction.
The progress made since 1854 is dependent on and embraces improvements in gun construction, rifling and breech mechanisms.
Considerable obscurity exists as regards the means adopted for mounting the first cannon. From illuminations in contemporary manuscripts it appears that the earliest guns, which were trunnionless, were simply laid on the ground and supported by a timber framing at meats. each side, whilst the flat breech end rested against a Old Equipments. strong wood support let into the ground to prevent recoil. This arrangement was no doubt inconvenient, and a little later small cannon were fastened in a wooden stock by iron bands; larger guns were supported in massive timber cradles (fig. 3) and secured thereto by iron straps or ropes. The ponderous weight to be moved and the deficiency of mechanical means prevented these large cannon and their cradles from being readily moved when once placed in position. Laying was of the most primitive kind, and the bombard was packed up in its wood cradle to the required elevation once for all. When it was desired to breach a wall the bombard with its bed would be laid on the ground at about 100 yds. distance, the breech end of the gun or the rear end of the bed abutting against a solid baulk of wood fixed to the ground. “Mons Meg” was originally provided with a wood cradle.
|
| Redrawn from Mallet’s Construction of Artillery. |
| Fig. 3. — Primitive Gun-mounting. |
It is by no means certain when wheeled carriages were
