Ballistics and Experience: The Tough Job

Ballistics is the study of the movement of projectiles. Galileo studied the principles of motion to derive the parabolic form of the ballistic trajectory. One of the members of the Academie Royale des Sciences, F. Blondel, wrote a book on the art of shooting bombs in 1683. In England Robert Anderson published the book Genuine Use and Effects of the Gunne in 1674. These two books became reference works.

In 1684 Sir Isaac Newton published his treatise De motu (In motion) and in 1687 he published Principia Mathematica Philosophiae Naturalis (Mathematical Principles of Natural Philosophy). In two Memoires published in 1719 and 1721 in the Acta eruditorum, Bernoulli also gave mathematical solutions to the science of ballistics. Eulke Robins published New Principles of Gunnery in London in 1742 and Euler expanded on mathematical solutions of equations of motion within the framework of ballistic theory. In 1753 he wrote Memoires de Berlin published by the Berlin Academy of Sciences and his study was entitled ‘Recherches sur la veritable courbe que decrivent les corps jetes dans l’air on dans un autre fluide’.

Thanks to the work of Robins and Euler, schools of artillery and military engineering could offer training to military engineers and the school of bombardiers started to teach in a scientific manner. Complicated formulae took into consideration the resistance of the atmospheric medium, the velocity and acceleration of the initial motion and a ballistic coefficient. Ballistics was no longer an art but was developing into a science.

In Malta the building which is today the Fortifications Information Centre close to St Andrew’s Bastions was used as an artillery school and the bastions were used to mount and shoot cannon.

During the first half of the eighteenth century, bombardiers often referred to studies published by the French mathematician Bélidor, who experimented with gunpowder charges at the La Fère artillery school in the North of France. He claimed to have discovered that the charges used to fire a cannonball were too high and that the amount of gunpowder used was only making warfare more heavy and more expensive.

Bélidor obtained permission from the court of France to conduct experiments using 24, 16, 12, 8 and 4-pounder cannons (the number referring to the weight of the cannon ball and not to the weight of the cannon). These experiments were conducted on 19 October 1739. He concluded that by reducing the charge, the range of the projectile would

Bottom left: Warship from a map by Matthaus Seutter c.1730.

Bottom right: Foundry marked on one of the trunnions of the cannon at Wignacourt Tower, St Paul's Bay.

Detail from a 17th century map by Homann.

The bombardier was considered to be the most important member of the guards on duty and was usually the capo mastro or castellano in charge of the tower. He was paid more than the ordinary guards and had to be literate and understand mathematics.

actually increase. The best weight of gunpowder needed to fire the projectile, he claimed, was of three eights the weight of the cannonball. The only exception was the 4-pounder cannon which fired best with gunpowder weighing half the weight of the projectile. These experiments were repeated between 8 and 11 June 1740 under the direction of the knight d’Abbouille, commander of artillery in France, and the same results were recorded.

The original manuscript with these results was brought personally to Malta by the knight de Turgot who commanded one of the Order of St John’s galleys in the Mediterranean. These results led to arrangements for bombardiers to decrease the gunpowder charge in their cannons both on land as well as on sea. The capomastro Triganze, head of artillery on the ship San Gio was one of those who started implementing these changes.

Experiments in Malta

This theory began to be questioned. In Malta a number of experiments were conducted using three bronze cannons which were judged to be of perfect quality; these were a 24-pounder produced in Barcellona in 1724 by Ribot, a 12-pounder produced in Malta in 1735 by Luigi Boiciut, and a 4-pounder produced in 1694. These cannons were placed on their wooden platform on the rampart of the Carafa Bastions under the keep of St Elmo Castle and directed north west towards St George’s Bay. A fine gunpowder of France was used for these experiments.

Interesting to note is the instruments used by the bombardier during these experiments. These included a balance to weigh the gunpowder, the projectile and the wick. Another essential instrument was the quadrant which was an instrument used to measure angles up to 90 degrees. The term quadrant, meaning one fourth, refers to the fact that early versions of this instrument were derived from astrolabes (used by astronomers and navigators to measure the altitude above the horizon of a celestial body) and this instrument was essentially a quarter of an astrolabe.

The instrument used in the experiments in Malta to calculate the angle of the cannon above the horizontal line was not a quadrant but a semi-circular copper rod of 27cm diameter to which a lead weight was hung using a very fine silk line. This copper rod was attached to a wooden rod about 195cm long which was inserted in the bore of the cannon. A thermometer of Mercury of Reaumur was also used as the ambient temperature was considered to be another variant. Callipers were used to measure the size of the bore of the cannon as well as the size of the cannonball.

The results of these experiments clearly showed that, contrary to those conducted by Bélidor and the knight d’Abbouille, the more

gunpowder used the further away the cannon ball was shot. For example, gunpowder weighing 3.17kg projected cannon balls up to 2621m away while gunpowder weighing 4.53kg projected the cannon balls up to 2954m distance.

Another experiment was conducted in Malta to compare the fine gunpowder which was used on the vessels of the Order of St John with the gunpowder from Genova. The latter was more similar to the coarse grain gunpowder used by the French artillery and that used during the experiments conducted by Bélidor and d’Abbouille. When using the gunpowder of Genova, incresing the amount of this gunpowder above a certain weight did not lead to any increase in the distance of the shot.

This experiment showed that apart from the quantity, the quality of the gunpowder determined the efficiency of the shot. There were a number of different sources of gunpowder stored in the different ‘magazini’ and ‘polveristi’ in Malta and Gozo. The different gunpowders were named after the place from where they were imported. Manuscripts dated 1775 and 1776 included gunpowder from France, Holland, Genova, Venice, Denmark, Lucca, Rome and Trieste. Gunpowder from France and Holland was the most popular with the Order of St John. It is interesting to note that the manuscript mentioned that the fine gunpowder of France was scarce at the gunpowder magazines at that time, and there was more gunpowder from Holland or Genova.

Other experiments in Malta conducted during the same period in the ditch of St Elmo, were intended to judge the penetration of the projectiles in a circular lead medallion of diameter 135cm and 21.6cm thick. The more the gunpowder used the bigger was the indentation in the medallion. Also, the bigger the projectile and the cannon used, the deeper the penetration of the projectile. These logical results were not maintained when the gunpowder of Genova, which was less fine and took longer to ignite, was used. In fact when the gunpowder used weighed more than three eighths the weight of the projectile, the penetration was even less.

Another experiment was conducted at St Elmo as well as at the school of the bombardiers at St Andrew’s Bastions with the help of the capo bombista Giuseppe Pace using a cannon manufactured by Giacomo Rocia in 1694. The cannon was placed on gravelled earth. Other shots were conducted both from land as well as from sea after the gravelled earth on which the cannon and its platform was placed was beaten to render it more compact. This led to the cannon ball being shot at a longer distance. Different platforms made of wooden strips were also used to observe the recoil and efficiency of the cannons.

No easy job!

The bombardier did not have an easy job. It was not enough to learn mathematics and physics to know how projectiles act. In order to know whether a cannon ball would hit an enemy ship from another ship, from a tower or battery (redoubts and entrenchments around our islands were rarely armed with cannon), he had to approximate the distance at which the enemy stood.

Equipment used to operate a Cannon (Manuscript Manual of the Navy of the Order)

The bombardier did not have an easy job. It was not enough to learn mathematics and physics to know how projectiles act.

This was however not enough. The type of cannon used was obviously most important as the length and uniformity of its bore, the shape of the muzzle and the recoil it produced were all important. The angle at which the cannon was placed, the carriage and platform on which it stood, the wind force and direction, the ambient temperature, the amount and quality of gunpowder poured by use of precise ladles to place the exact charge all had an effect on the result. Experiments also showed that the larger the angle of the cannon bore was from the horizontal, the more gunpowder was needed as the weight of the cannon ball exerted a greater weight on the gunpowder which took longer to ignite. Although theory was important, experience was still an asset.

The Status Animarum of various parishes reveal details about the people living there and events related to them. We come across various people who were bombardiers or assistant bombardiers in coastal towers or on the galleys of the order. Other trades also feature, varying from tailors to skarpar (shoemaker). The great majority were Maltese and at times petitions were forwarded by knights invoking the promotion of Maltese soldiers to bombardiere and capo bombardiere. Many men who served the order, including bombardiers, had a pension and families who lost a bread winner while on active duty were also given a pension. Sometimes bombardiers lost their lives at sea when their galley was attacked, but sometimes accidents occurred while igniting the charge.

Bombardiers in towers

The bombardier was considered to be the most important member of the guards on duty and was usually the capo mastro or castellano in charge of the tower. He was paid more than the ordinary guards and had to be literate and understand mathematics.

Garzes Tower, for example, was run by a resident bombardier and three soldiers. These soldiers were paid by the Order on a roster of three 24-hour shifts, and had to spend the night there. The castellan received an annual salary of 60 scudi and two oil measures, and was licensed to operate a tavern for the benefit of the tower’s soldiers and neighbouring inhabitants. The fixed salary of the resident bombardier was supplemented by 10 scudi, while each of the soldiers was paid 48 scudi annually Moreover, a small plot of arable land was assigned to the castellan and soldiers for their use.

While explaining the need to erect between 12 and 14 towers around the coasts of the island (13 were eventually built), Grand Master de Redin stated that at the time there were about 60 guard posts which had about four soldiers each. He wanted to erect the towers at his own expense and guard them with four people. Three of them were to be given a salary of 2 scudi per month each and the bombardiere was to be offered a salary of two and a half scudi per month. The Order would then be in a position to provide each tower with a ‘small piece of artillery’ but the guards would be paid by the Università.

In June 1722 the Congregation of War instructed that St Agatha’s Tower would be armed with five guns and manned by a garrison of four men as the tower became an essential part of the defence of the island. There had to be a resident bombardier and three militia men.

The garrison of Wignacourt Tower was commanded by a master bombardier. In 1792, the Congregation of War ordered that the redoubts at Ramla Bay in Gozo and at Mellieħa in Malta be armed with two 6-pounder and four 6-pounder guns respectively. These defence posts were to receive a complement of 6 bombardiers and 22 gun crew.

The bombardier of the Dwejra Tower received an annual salary of 60 scudi, with 40 scudi paid by the Order and 20 scudi by the Università. He also received 2 scudi for oil consumption and was entitled to harvest the underlying saltpans.

On 10 February 2020, for the 410th anniversary of the laying of the first stone of the Wignacourt Tower, the ‘Show of Arms’ re-enactment association shot the 4-pounder cannon manufactured in 1782 by Akers Bruck foundry in Sweden as demonstrated by the sign AB on one of the trunnions. This was the oldest cannon to be fired on our island. n

Stanley Farrugia Randon is a medical doctor and a council member of Din l-Art Ħelwa