In respect of design, the newly acquired knowledge of the true principles governing internal ballistics began gradually, in the latter part of the century, to show its effect. Hitherto, ever since gunpowder had been in military use, pieces had been cast in masses of varying size and shape and ornamented to please the fancy of the founder. Cannon had been made with double or triple reinforces of metal, so that their exterior surface was stepped longitudinally from muzzle to breech. Experience probably pointed out on many occasions the bad design of a piece whose sections showed sudden alterations in shape; but it was not till after the middle of the eighteenth century that this consideration was discussed by a professional. “Since powder acts uniformly and not by starts it is hard to judge from whence this ridiculous custom has arisen.... There should be no breakings in the metal.” The piece, continues Muller, should be of cylindrical bore, and its outer contour should be a curve slightly concave, corresponding presumably to the curve of the powder pressure. But as this curve would be difficult to find, he recommends a sloping straight line from breech to muzzle as sufficiently exact for practical purposes.

Innumerable experiments were made in the first half of this century with a view to improving the efficiency of combustion in guns, and much argument centred round such subjects as the shape of the chamber and the position of the vent. In France pieces were adopted having spherical chambers: it being proved that, with the charge concentrated in a spherical cavity, as much power could be obtained as from a larger and heavier flush-chambered gun. But such pieces were dangerous. Not only was their recoil so violent as to break their carriages, but many good gunners lost their arms while charging chambers in which smouldering debris lay hidden. The spherical chamber was abandoned.62

It may be said that the design and manufacture of guns has now entered the scientific stage. Art there still is, but it lies below the surface. The old “vain ornaments” preserved by tradition are thrown away: the scrolls, mouldings, and excrescences which broke the surface of the metal; the ogees, fillets, and astragals which ran riot over the products of some foundries; the muzzle swells which by their weight caused the chase to droop; the grotesque cascabels. All mouldings, said Muller, should be as plain and simple as possible; the trunnions should be on the axis of the piece; the windage of all types of guns should be smaller, and there should be more moderation in the charges used.

In time all these improvements came. The smooth-bore gun, strengthened and simplified, preserved its establishment in the navy far into the nineteenth century, as will later appear. For the present we must confine ourselves to noting that, in the final stages of its evolution it received improvement in form from two distinguished artillerists whose influence was progressive in the whole realm of gunnery: Generals Congreve63 and Blomefield.64 There is yet another eminent officer of this period to whom the navy owes a debt incalculable: Who can assess the value of the work done by General Sir Howard Douglas in his classic treatise on Naval Gunnery?

To the foregoing survey of the evolution of heavy ordnance we now append a few notes on the evolution of the material of purely land artillery: from which it will be seen that, while the intensive competition of great armies resulted in much of this latter evolution originating among the continental powers, the share of this country in initiating improvement was, in the latter years, by no means negligible.

§

It will be noted by the student of European history as significant, that superiority of artillery material has almost invariably marched with national power. Thus in the past the evolution of artillery has been the monopoly of no one nation; it has been progressed by each in turn; each in turn has attained superiority, and each has contributed something of importance to it, in the day of its greatness.

Two ancient and preventable practices seem to have operated in chief measure to retard the progressive development of a mobile land artillery: first, the custom of setting the trunnions of a gun at an appreciable distance below the horizontal plane of the gun-axis; second, the custom of making small pieces relatively longer than those of larger calibre.

The first guns had no trunnions. To obtain the requisite angle of elevation the piece was laid in a dug-out trunk or carriage and this carriage was set on trestles; in which manner, it appears, the English at the siege of Orleans in A.D. 1428 “threw into the town from their bombards large numbers of stones which, flying over the walls, smashed in the roofs of houses.”65 During the fifteenth century trunnions came into use, and the carriages were mounted on wheels. In his Introduction of Artillery into Switzerland a French writer, Colonel Massé, has given an account of the early evolution of an artillery of position, as used by the Swiss and their enemies in the fifteenth century. The huge siege bombards, possessed by most of the great cities at the end of the fourteenth century, were too cumbrous for transport. Built up of welded and coiled iron, and therefore without trunnions, they were replaced, toward A.D. 1443, by lighter pieces on wheeled carriages. And before the Burgundian War “coulevrines de campagne” were being cast in Switzerland, of bronze, with trunnions to give each piece an elevation independently of its carriage. Relics are still preserved which show the gun-trunnion in its early stages, as embodied in the Burgundian artillery of Charles the Bold. The first method of obtaining elevation for the gun was by hinges or trunnions on the front of the carriage or trunk, in combination with a curved rack erected on the trail for supporting the rear end. Then the trunk disappeared; the trunnions were cast on the gun, whose cascabel was supported by a cross-pin between the flanks of the trail; and then the cross-pin was made removable, and a series of holes was provided for its reception, to give the elevation desired. At first these trunnions were cast level with the gun axis; in Napoleon III’s treatise on artillery is a picture of a trunnion gun taken by the Swiss from Charles the Bold in 1476, and another of a cannon of Louis XI, cast in 1478, and in both cases the trunnions are level with the gun axis. But pieces cast later almost invariably had their trunnions set on a level with the bottom of the bore; partly, perhaps, for the insignificant reason given by Norton—that “lying somewhat under the concave cylinder of the bore they will the better support the great weight”—but primarily to ensure a downward pressure on the quoin or trail when discharge took place. The effect of this trivial alteration was enormous. The impulse of the recoil was given a moment about the trunnion axis which, as the force of powders increased, produced an increasingly great downward pressure on the trail. Carriages, though made of massive scantlings, frequently broke; nor was it till the latter half of the eighteenth century that the cause was removed, the trunnions being raised nearer the axes of the guns and the carriages being thereby relieved of the excessive cross-strains which they had borne for nearly three hundred years. Muller, in his Artillery, refers to the “absurd method” of placing the trunnions so low and, in the year 1768, points out the advantages to be gained by raising them. “Writers do not appear to have had any idea,” says Favé, “of the effect which the position of the trunnions had on the stressing of the carriage.” Scharnhorst the Prussian gives as an important advantage to be gained by raising the trunnions, the larger wheels which could be employed without adding to the height of the gun above the ground.

Progress was also checked by the great length given to the smaller varieties of cannon. With the fine powder of the Middle Ages a great length of barrel was necessary to ensure complete combustion, and such primitive observations as were made all seemed to prove that, the longer the barrel the greater the range. But with the introduction of corned powder a reduction in length should have been possible. No such change was made. Tradition had consecrated long guns, and official standardization of types afterwards helped to oppose any innovation in this respect until the eighteenth century, with few exceptions.

To Charles V of Spain belongs the credit for the first systematic classification of guns. In his hands artillery had, for the first time, become an efficient instrument of battle in land campaigns, and all Europe saw that, in his batteries of bronze trunnion-guns, on wheeled carriages, firing cast-iron balls against foe or crumbling masonry, a new power had arisen.66 The emperor, experiencing the inconvenience of a multiplicity of types and calibres, sought to simplify his material. Accordingly, in the year 1544 or shortly before, he approved seven models to which all pieces in use throughout the vast possessions of the Spanish monarchy were thenceforth to conform. These seven types comprised a cannon (a 40-pounder), a cannon-moyen (24-pounder), two 12-pounder culverins, two 6-pounder culverins, and a 3-pounder falcon.

The French soon improved on Charles’ example. The oldest patterns of their cannon, according to a table given by St. Remy in his Mémoires, were of a uniform length of ten feet. In A.D. 1550 Henri II issued an edict restricting the number of different calibres to six, named as follows:—

Canon, a 33-pounder, 10½ feet long, weighing 5200 livres, drawn by 21 horses.

Grande coulevrine, a 15-pounder, 11 feet long, weighing 4000 livres, drawn by 17 horses.

Coulevrine bâtarde, a 7-pounder, 9 feet long, weighing 2500 livres, drawn by 11 horses.

Coulevrine moyenne, a 2-pounder, 8½ feet long, weighing 1200 livres, drawn by 4 horses.

Faucon, a 1-pounder, 7½ feet long, weighing 700 livres, drawn by 3 horses.

Fauconneau, a ¾-pounder, 7 feet long, weighing 410 livres, drawn by 2 horses.

These dimensions are only a rough approximation. In the year 1584 two other types, found useful by the Spaniards in the Low Countries, were included—a 12- and a 24-pounder.

The relatively greater lengths of the small pieces will be noted. As it was with the French, so it was with other nations, and the list of Italian ordnance given in Tartaglia’s Art of Shooting shows a general resemblance to that of Henri II. The desire for a maximum of ranging power, and the necessity of making the smaller pieces long enough to enter the embrasures of fortifications, and strong enough to fire many more rounds than those of the largest size, tended to cause an augmentation in their size and weight; difficulties of transport had an effect in imposing a limit of weight on the largest guns which in the case of the smaller pieces did not operate to the same degree.

Nevertheless, the French possessed, from 1550 onwards, an organized artillery suitable for transport on campaigns. The six calibres were mounted on wheeled carriages, horse-drawn, from which they could be fired; they were moved, muzzles foremost, with their ponderous trails dragging on the ground in rear.

At that point French artillery remained, or with little advance beyond it, until the middle of the eighteenth century. In the Germanic states, on the other hand, important progress was made: by the end of the sixteenth century shorter pieces, shell-fire from mortars, and the use of elevated fire for varying ranges, had been adopted. But the chief centre of artillery progress at the end of the sixteenth century was the Low Countries, then in the thick of their warfare with Spain. “In their glorious struggle for independence their artillery contrived to avail itself of the latest and best theory and practice, to employ cannons and carriages of simplicity and uniformity; and it has endowed the art of war with two inventions of the first order—the hand-grenade and the bomb.”67

In the first half of the seventeenth century the genius of Gustavus Adolphus gave a new value to land ordnance. He made it mobile. He divided his artillery into two categories, Siege and Field, and for the latter devised the famous light “leather guns” which, operating in mass on certain points, had an important effect on the issue of battles. But after his death at Lützen in 1632 the effort to attain mobility relaxed; an increase in the strength of powders at this time rendered the possibility still more remote; and it was not until the following century that the Prussians, under Frederick the Great, evolved a satisfactory light artillery. Both in Prussia and in Austria great efforts were made, in the middle of the eighteenth century, to evolve a mobile and efficient ordnance. The Seven Years’ War found the former state experimenting with pieces varying in weight between eighty and a hundred and fifty times the weight of their ball; and in 1762 a certain French observer, who was destined to become famous as one of the great artillery reformers of all time, wrote letters from Vienna describing the fine qualities of the Austrian service: with its pieces all sixteen calibres in length, all 115 times their balls in weight, all bored to their true nominal dimensions, and firing accurately spherical balls of correct size, with a small windage and a powder-charge of less than one-third the weight of the shot.

In the years immediately following the close of the Seven Years’ War the lessons learned at Vienna were translated into practice in France. By 1765 Gribeauval had begun his reorganization of the French material. In order to obtain mobility he made new models of 12, 8, and 4-pounders, very plain, unchambered pieces, each eighteen calibres in length, 150 times its own shot in weight, and firing well-fitting balls with unprecedented precision, with powder-charges of one-third the weight of the balls. Limbers, in the form of small-trucked bogies, had been in occasional use ever since the sixteenth century. Gribeauval introduced large-wheeled limbers, and dragged his 12-pounders by six, his 8- and 4-pounders by four horses. From the number of horses, as compared with that of the edict of Henri II, one can measure the progress made in two centuries. The whole of Gribeauval’s material was designed to afford rapid transport and rapid and accurate fire; interchangeability of wheels and other parts formed a novel and important element of the standardization which he accomplished. Iron axle-trees, cartridges (used with effect by Gustavus in the preceding century), elevating screws, tangent scales, and other improvements were adopted under his authority. But, “Gribeauval could not force on France the two great inventions of the century—the limber-box and the Horse Artillery.”68

The horse, or flying, artillery, designed to be attached to, and supported by, cavalry, as field or foot artillery was attached to infantry, was a Prussian invention. It was adopted by France after the outbreak of the Revolution, and almost simultaneously it appeared in the British army.69

By the end of the century all the great Powers had adopted Gribeauval’s system in most of its important parts: notably in the grouping of artillery into the three categories—siege, field, and coast defence. Progress continued. In the opening years of the next century a new competitor among the Powers began to attract attention by its proficiency. “In the first campaigns of the Revolution the English artillery showed itself less advanced than that of several other powers. But so well did it succeed in ameliorating its condition that when it reappeared on the Continent to take an active part in the Peninsular War it was seen to be itself worthy in its turn to serve as a model.”

This is the tribute paid by Colonel Favé.

It is evident from his further remarks that the English artillery surprised its adversaries, not only by its superior mobility, but by the effectiveness of its innovations, two of which, especially, proved to be inventions of the first order—Shrapnel’s projectiles and Congreve’s war-rockets. France recognized the high efficiency of its opponent artillery, and some years later adopted a material embodying some of its most important features. Experiments were made, and comparative trials carried out, with modified English and modified Gribeauval equipments. The former were preferred, and a new series of designs was introduced and approved: this becoming known as “the system of 1827.”

Three years later war experience led to investigations in France which caused a revolution in artillery material. In a few years’ time smooth-bore cannon were being converted to rifles, for use both on land and sea.