Gun laying is the process of aiming an artillery piece, such as a gun, howitzer, or mortar, on land or at sea, against surface or air targets. It may be laying for direct fire, where the gun is aimed to a rifle, or indirect fire, where firing data is calculated and applied to the sights; the term includes automated aiming using, for example, radar-derived target data and computer-controlled guns. Gun laying means moving the axis of the bore of the barrel in two planes and vertical. A gun is "traversed" to align it with the target, "elevated" to range it to the target. Gun laying is a set of actions to align the axis of a gun barrel so that it points in the required direction; this alignment is in vertical planes. Gun laying may be for direct fire, where the layer sees the target, or indirect fire, where the target may not be visible from the gun. Gun laying has sometimes been called "training the gun". Laying in the vertical plane uses data derived from trials or empirical experience. For any given gun and projectile types, it reflects the distance to the target and the size of the propellant charge.
It incorporates any differences in height between gun and target. With indirect fire, it may allow for other variables as well. With direct fire, laying in the horizontal plane is the line of sight to the target, although the layer may make allowance for the wind, with rifled guns the sights may compensate for projectile "drift". With indirect fire the horizontal angle is relative to something the gun's aiming point, although with modern electronic sights it may be a north-seeking gyro. Depending on the gun mount, there is a choice of two trajectories; the dividing angle between the trajectories is about 45 degrees, it varies due to gun dependent factors. Below 45 degrees the trajectory is called "low angle", above 45 degrees is "high angle"; the differences are that low angle fire has a shorter time of flight, a lower vertex and flatter angle of descent. All guns have mountings that support the barrel assembly. Early guns could only be traversed by moving their entire carriage or mounting, this lasted with heavy artillery into World War II.
Mountings could be fitted into traversing turrets on coast defences or tanks. From circa 1900 field artillery carriages provided traverse without moving trail; the carriage, or mounting enabled the barrel to be set at the required elevation angle. With some gun mounts it is possible to depress the gun, i.e. move it in the vertical plane to point it below the horizon. Some guns require a near-horizontal elevation for loading. An essential capability for any elevation mechanism is to prevent the weight of the barrel forcing its heavier end downward; this is helped by having trunnions at the centre of gravity, although a counterbalance mechanism can be used. It means the elevation gear has to be strong enough to resist considerable downward pressure but still be easy for the gun layer to use; until recoil systems were invented in the late 19th century and integrated into the gun carriage or mount, guns moved backwards when they fired, had to be moved forward before they could be laid. However, where the recoil forces were transferred directly into the ground, did not always require such movement.
With the adoption of recoil systems for field artillery, it became normal to pivot the saddle on the lower carriage this "top traverse" was only a few degrees but soon offered a full circle for anti-aircraft guns. The introduction of recoil systems was an important milestone; the earliest guns were loaded from the muzzle. They were little more than bare barrels moved in wagons and placed on the ground for firing wooden frames and beds were introduced. Horizontal alignment with the target was by eye, while vertical laying was done by raising the muzzle with timber or digging a hole for the closed end. Gun carriages were introduced in the 15th century. Two large-diameter wheels, axle-tree and a trail became the standard pattern for field use; the barrel was mounted in a wooden cradle with trunnions to mount it on the carriage. As technology improved, the trunnions became part of the cradle was abandoned, they were large and heavy. Horizontal alignment was a matter of moving the trail. To achieve the required elevation angle, various arrangements were used.
At the simplest, it was wedges or quoins between the breech and the trail, but wooden quadrants, or simple scaffolds mounted on the trail, were used to support the breech and provided larger choice of elevation angle. Screw elevation devices were used as early as the 16th century; however and some fortress carriages and mounting evolved differently. Field mobility was not required, so large wheels and trails were irrelevant. Headspace below decks was low; this led to compact carriages on four small wheels. Large horizontal traverses were more difficult, but such things were unnecessary when shooting broadside. However, in fortresses wider traverse was required. One solution was slide mountings. Wide traverse was useful on some shipmounted guns. Laying required sights. At its simplest, this means nothing more than aiming the guns in the right direction. However, various aids emerged. Horizontal aiming involved sighting along the barrel, this was enhanced by a notch made in the ring around the barrel at th
Midvale Steel was a succession of steel-making corporations whose flagship plant was the Midvale Steel Works at Nicetown, Pennsylvania, which operated from 1867 until 1976. It was in the 1880s that Frederick Winslow Taylor rose through the ranks at Midvale, from lathe operator, to gang boss, to engineer, to chief engineer of the works. During this time he developed the core of his philosophy of scientific management; the company was most notable for producing high-quality steels and for providing the casting and machining needed to use them in special applications such as heavy artillery. Midvale helped pioneer the steel formulas used in the early automotive industry. Midvale was never a large company, the flagship Nicetown plant was, in the management's own words, "never a'tonnage' plant"; that is, unlike larger steelmakers, they did not measure their success in terms of the sheer tonnage they could manage to produce per year. Midvale's niche in the steel industry was defined early on by a scientific approach to metallurgy during the transitional era when steelmaking transformed from black art to applied science.
After the rest of the industry caught up in terms of that transition, Midvale continued for decades to maintain a niche for itself in the area of the market defined by high quality and development, special applications. The company began in 1867 as the William Butcher Steel Works; the products that founders William Butcher, Jr. and Philip Syng Justice planned to produce were cast-steel locomotive tires and cast-steel forgings, with a plan to make a promising new product: steel rails, which would be far superior to older iron ones. At about this time in nearby Bethlehem, the predecessor company of Bethlehem Steel was getting into the steel rail business; the Nicetown site was chosen because plenty of the anthracite coal that moved by river and rail from northeast Pennsylvania passed by Nicetown on its way to Port Richmond. Anthracite was superior to bituminous coal for steelmaking. Nicetown's proximity to one of the principal locomotive-building plants of the western hemisphere, the Baldwin Locomotive Works, was another benefit of the site.
Midvale began with the crucible process, but two years after its founding began using the open-hearth process, which would in time replace the crucibles. The company's early years were rocky. A principal investor, the quiet but immensely influential American engineer and businessman William Sellers, forced out Butcher, whose adherence to the idea of steelmaking as an obscure art of secret recipes did not serve him well when his recipes did not turn out right and he was unable to analyze why. With Butcher gone, Sellers renamed. Kanigel states that the name reflected the fact that Midvale was equidistant from the Schuylkill and Delaware rivers; the emphasis was that it was not directly on either river, but between them. In 1872, Sellers brought in a Yale-trained chemist with a talent for organization named Charles Augustus Brinley, who used applied science to straighten out the steelmaking formulas and processes, along the way analyzing and salvaging the scrap that had accumulated during Butcher's tenure.
Brinley hired a fellow Yale chemist, to be his assistant. Brinley and Sellers led Midvale to a period of prosperity. By the Centennial Exposition in 1876, they "were making Midvale into a company as congenial to a scientific approach to industrial problems as could be found anywhere in America", it was in the 1880s that Frederick Winslow Taylor rose through the ranks at Midvale, from lathe operator, to gang boss, to engineer, to chief engineer of the works. During this time he developed the core of his philosophy of scientific management, which became enormously influential throughout the field of industrial engineering. Other notable people who worked for Midvale Steel or in close cooperation with it include Henry Gantt, James Buchanan Eads, Theodore Cooper, Francis B. Foley. Charles E. Brinley, president of Baldwin Locomotive Works during the World War II era, appears to have been the son of Charles A. Brinley, Midvale's metallurgical leader. Besides the railroad industry, one of the most important client industries for Midvale became armaments.
During the late 19th and early 20th centuries, among many American steel companies, Bethlehem Steel and Midvale Steel became the Krupps of the Americas. An influential product of theirs since the 1910s and improved through the 1930s was the Midvale Unbreakable capped armor-piercing projectiles for warships, their innovation attempts at armor-making were less successful. Kanigel, The One Best Way: Frederick Winslow Taylor and the Enigma of Efficiency, Viking, ISBN 978-0-670-86402-7. Midvale Company, The Seventy-fifth Anniversary of the Midvale Com
World War I
World War I known as the First World War or the Great War, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously described as "the war to end all wars", it led to the mobilisation of more than 70 million military personnel, including 60 million Europeans, making it one of the largest wars in history, it is one of the deadliest conflicts in history, with an estimated nine million combatants and seven million civilian deaths as a direct result of the war, while resulting genocides and the 1918 influenza pandemic caused another 50 to 100 million deaths worldwide. On 28 June 1914, Gavrilo Princip, a Bosnian Serb Yugoslav nationalist, assassinated the Austro-Hungarian heir Archduke Franz Ferdinand in Sarajevo, leading to the July Crisis. In response, on 23 July Austria-Hungary issued an ultimatum to Serbia. Serbia's reply failed to satisfy the Austrians, the two moved to a war footing. A network of interlocking alliances enlarged the crisis from a bilateral issue in the Balkans to one involving most of Europe.
By July 1914, the great powers of Europe were divided into two coalitions: the Triple Entente—consisting of France and Britain—and the Triple Alliance of Germany, Austria-Hungary and Italy. Russia felt it necessary to back Serbia and, after Austria-Hungary shelled the Serbian capital of Belgrade on the 28th, partial mobilisation was approved. General Russian mobilisation was announced on the evening of 30 July; when Russia failed to comply, Germany declared war on 1 August in support of Austria-Hungary, with Austria-Hungary following suit on 6th. German strategy for a war on two fronts against France and Russia was to concentrate the bulk of its army in the West to defeat France within four weeks shift forces to the East before Russia could mobilise. On 2 August, Germany demanded free passage through Belgium, an essential element in achieving a quick victory over France; when this was refused, German forces invaded Belgium on 3 August and declared war on France the same day. On 12 August and France declared war on Austria-Hungary.
In November 1914, the Ottoman Empire entered the war on the side of the Alliance, opening fronts in the Caucasus and the Sinai Peninsula. The war was fought in and drew upon each power's colonial empire as well, spreading the conflict to Africa and across the globe; the Entente and its allies would become known as the Allied Powers, while the grouping of Austria-Hungary and their allies would become known as the Central Powers. The German advance into France was halted at the Battle of the Marne and by the end of 1914, the Western Front settled into a battle of attrition, marked by a long series of trench lines that changed little until 1917. In 1915, Italy opened a front in the Alps. Bulgaria joined the Central Powers in 1915 and Greece joined the Allies in 1917, expanding the war in the Balkans; the United States remained neutral, although by doing nothing to prevent the Allies from procuring American supplies whilst the Allied blockade prevented the Germans from doing the same the U. S. became an important supplier of war material to the Allies.
After the sinking of American merchant ships by German submarines, the revelation that the Germans were trying to incite Mexico to make war on the United States, the U. S. declared war on Germany on 6 April 1917. Trained American forces would not begin arriving at the front in large numbers until mid-1918, but the American Expeditionary Force would reach some two million troops. Though Serbia was defeated in 1915, Romania joined the Allied Powers in 1916 only to be defeated in 1917, none of the great powers were knocked out of the war until 1918; the 1917 February Revolution in Russia replaced the Tsarist autocracy with the Provisional Government, but continuing discontent at the cost of the war led to the October Revolution, the creation of the Soviet Socialist Republic, the signing of the Treaty of Brest-Litovsk by the new government in March 1918, ending Russia's involvement in the war. This allowed the transfer of large numbers of German troops from the East to the Western Front, resulting in the German March 1918 Offensive.
This offensive was successful, but the Allies rallied and drove the Germans back in their Hundred Days Offensive. Bulgaria was the first Central Power to sign an armistice—the Armistice of Salonica on 29 September 1918. On 30 October, the Ottoman Empire capitulated. On 4 November, the Austro-Hungarian empire agreed to the Armistice of Villa Giusti after being decisively defeated by Italy in the Battle of Vittorio Veneto. With its allies defeated, revolution at home, the military no longer willing to fight, Kaiser Wilhelm abdicated on 9 November and Germany signed an armistice on 11 November 1918. World War I was a significant turning point in the political, cultural and social climate of the world; the war and its immediate aftermath sparked numerous uprisings. The Big Four (Britain, the United States, It
21 cm Mörser 16
The 21 cm Mörser 16, or 21 cm Lange Mörser M 16/L14.5, was a heavy howitzer used by Germany in World War I and World War II. It was based on the earlier 21 cm Mörser 10, but had a longer barrel, a Gun shield and other refinements, it broke down into two loads for transport, but the Germans rebuilt surviving guns during the 1930s with rubber-rimmed steel wheels to allow for motor traction in one piece with a limber under the trail and removed the gunshield. In German service, it used two shells, the 21 cm Gr 18 that weighed 113 kilograms and the 21 cm Gr 18 Be concrete-piercing shell of 121.4 kilograms with a filler of 11.61 kilograms of TNT. They remained in first-line use with the Germans until replaced by the 21 cm Mörser 18 by about 1940. Afterwards, they were used for training; the Swedes bought a dozen weapons in 1918 from the Germans and they remained in service until 1950. The Swedes had their own concrete-piercing shells, the 210 tkrv 51/65-ps R-/33 weighing 120.75 kilograms, which had dispersion problems as the Finns found out.
The Finns bought four of these from the Swedes during the Winter War, although they did not participate in the war because the Finns lacked vehicles strong enough to tow their great weight to the front. This had been rectified before the Continuation War and the Finns equipped the 10th Separate Super-Heavy Artillery Battery with them for the duration of the war, they were put into reserve after the war and remained there until the late 1960s before being discarded. 220 mm TR mle 1915/1916 – French equivalent BL 8 inch Howitzer Mk VI – VIII – British equivalent firing lighter shell Scheibert, Horst. Deutsche Artillerie 1934-1945: Eine Dokumentation in Text, Skizzen und Bildern: Ausrüstung, Ausbildung, Führung, Einsatz. Limburg/Lahn, Germany: C. A. Starke. Chamberlain, Terry Gander, Peter. Weapons of the Third Reich: an encyclopedic survey of all small arms and special weapons of the German land forces, 1939-1945. Garden City, N. Y.: Doubleday. ISBN 0-385-15090-3. Hogg, Ian. Twentieth-century artillery.
New York: Barnes & Noble Books. ISBN 0-7607-1994-2. Jäger, Herbert. German artillery of World War One. Marlborough: Crowood Press. ISBN 1-86126-403-8. Engelmann, Joachim. German heavy mortars. West Chester, PA: Schiffer. ISBN 088740-322-0. Video clips on YouTube 21 cm Mörser 10/16 on Landships the Mörser 16 on Jägerplatoon List and pictures of World War I surviving 21cm Morsers 16
Battle of Passchendaele
The Battle of Passchendaele known as the Third Battle of Ypres, was a campaign of the First World War, fought by the Allies against the German Empire. The battle took place on the Western Front, from July to November 1917, for control of the ridges south and east of the Belgian city of Ypres in West Flanders, as part of a strategy decided by the Allies at conferences in November 1916 and May 1917. Passchendaele lay on the last ridge east of Ypres, 5 mi from a railway junction at Roulers, vital to the supply system of the German 4th Army; the next stage of the Allied plan was an advance to Thourout–Couckelaere, to close the German-controlled railway running through Roulers and Thourout. Further operations and a British supporting attack along the Belgian coast from Nieuwpoort, combined with Operation Hush, were to have reached Bruges and the Dutch frontier; the resistance of the 4th Army, unusually wet weather, the onset of winter and the diversion of British and French resources to Italy, following the Austro-German victory at the Battle of Caporetto, enabled the Germans to avoid a general withdrawal, which had seemed inevitable in early October.
The campaign ended in November, when the Canadian Corps captured Passchendaele, apart from local attacks in December and in early 1918. The Battle of the Lys and the Fifth Battle of Ypres were fought before the Allies occupied the Belgian coast and reached the Dutch frontier. A campaign in Flanders has remained so; the British Prime Minister, David Lloyd George, opposed the offensive, as did General Ferdinand Foch, the French Chief of the General Staff. Field Marshal Sir Douglas Haig, commanding the British Expeditionary Force, did not receive approval for the Flanders operation from the War Cabinet until 25 July. Matters of dispute by the participants and historians since the war, have included the wisdom of pursuing an offensive strategy in the wake of the Nivelle Offensive, rather than waiting for the arrival of the American Expeditionary Force in France; the choice of Flanders over areas further south or the Italian front, the climate of Flanders, the choice of General Hubert Gough and the Fifth Army to conduct the offensive, debates over the nature of the opening attack and between advocates of shallow and deeper objectives, remain controversial.
The passage of time between the Battle of Messines and the Battle of Pilckem Ridge, the first Allied attack of the Third Battle of Ypres, the extent to which the internal troubles of the French armies motivated British persistence with the offensive, the effect of the exceptional weather, the decision to continue the offensive in October and the human cost of the campaign for the soldiers of the German and British armies, have been argued over. Belgium had been recognised in the Treaty of London as a sovereign and neutral state after the secession of the southern provinces of the Netherlands in 1830; the German invasion of Belgium on 4 August 1914, in violation of Article VII of the treaty, was the British casus belli against Germany. British military operations in Belgium began with the arrival of the British Expeditionary Force at Mons on 22 August. Operations in Flanders began during the Race to the Sea, reciprocal attempts by the French and German armies to turn their opponents' northern flank, through Picardy and Flanders.
On 10 October, Lieutenant-General Erich von Falkenhayn, the Chief of Staff of the Oberste Heeresleitung, ordered an attack towards Dunkirk and Calais, followed by a turn south behind the Allied armies, to gain a decisive victory. On 16 October, the Belgians and some French reinforcements began the defence of western Belgium and the French Channel ports, at the Battle of the Yser; when the German offensive failed, Falkenhayn ordered the capture of Ypres to gain a local advantage. By 18 November, the First Battle of Ypres had ended in failure, at a cost of 160,000 German casualties. In December 1914, the British Admiralty began discussions with the War Office, for a combined operation to re-occupy the Belgian coast but were obliged to conform to French strategy and participate in offensives further south. Large British offensive operations in Flanders were not possible in 1915, due to a lack of resources; the Germans conducted their own Flanders offensive at the Second Battle of Ypres, making the Ypres salient more costly to defend.
Sir Douglas Haig succeeded Sir John French as Commander-in-Chief of the BEF on 19 December 1915. A week after his appointment, Haig met Vice-Admiral Sir Reginald Bacon, who emphasised the importance of obtaining control of the Belgian coast, to end the threat posed by German U-boats. Haig was sceptical of a coastal operation, believing that a landing from the sea would be far more difficult than anticipated and that an advance along the coast would require so much preparation, that the Germans would have ample warning. Haig preferred an advance from Ypres, to bypass the flooded area around the Yser and the coast, before attempting a coastal attack to clear the coast to the Dutch border. Minor operations took place in the Ypres salient in 1916, some being German initiatives to distract the Allies from the preparations for the offensive at Verdun and attempts to divert Allied resources from the Battle of the Somme. Other operations were begun by the British to regain territory or to evict the Germans from ground overlooking their positions.
Engagements took place on 12 February on 14 February at Hooge and Sanctuary Wood. There were actions from 14–15 February and 1–4 March at The Bluff, 27 March – 16 April at the St Eloi
Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999. Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor & Sanderson and Vickers' brother William owned a steel rolling operation. Edward's investments in the railway industry allowed him to gain control of the company, based at Millsands and known as Naylor Vickers and Company, it began life making steel castings and became famous for casting church bells. In 1854 Vickers' sons Thomas and Albert joined the business and their considerable talents – Tom Vickers as a metallurgist and Albert as a team-builder and salesman – were key to its subsequent rapid development. "Its great architects," the historian Clive Trebilcock writes, "Colonel T. E. and Albert Vickers... provided both inspired technical leadership... and astute commercial direction. Both men were autocrats by temperament.
The company went public in 1867 as Vickers, Sons & Company and acquired more businesses, branching out into various sectors. In 1868 Vickers began to manufacture marine shafts, in 1872 they began casting marine propellers and in 1882 they set up a forging press. Vickers produced their first armour plate in 1888 and their first artillery piece in 1890. Vickers bought out the Barrow-in-Furness shipbuilder The Barrow Shipbuilding Company in 1897, acquiring its subsidiary the Maxim Nordenfelt Guns and Ammunition Company. At the same time, to become Sons & Maxim. Ordnance and ammunition made during this period, including World War I, was stamped V. S. M; the yard at Barrow became the "Naval Construction Yard". With these acquisitions, Vickers could now produce a complete selection of products, from ships and marine fittings to armour plate and a whole suite of ordnance. In 1901 the Royal Navy's first submarine, Holland 1, was launched at the Naval Construction Yard. In 1902 Vickers took a half share in the famous Clyde shipyard John Company.
Further diversification occurred in 1901 with the acquisition of a proposed business, incorporated as The Wolseley Tool and Motor Car Company and in 1905 the goodwill and patent rights of the Siddeley car. In 1911 a controlling interest was acquired in the torpedo manufacturers. In 1911 the company name was changed to Vickers Ltd and expanded its operations into aircraft manufacture by the formation of Vickers Ltd and a Vickers School of Flying was opened at Brooklands, Surrey on 20 January 1912. In 1919, the British Westinghouse electrical company was taken over as the Metropolitan Vickers Electrical Company. At the same time they came into Metropolitan's railway interests. A reorganisation during 1926 led to the retention of the rolling stock group: Metropolitan Carriage wagon and Finance Company and The Metropolitan -Vickers Company and the disposal of: Vickers-Petters Limited, British Lighting and Ignition Company, the Plywood department at Crayford Creek, Canadian Vickers, William Beardmore and Co, Wolseley Motors.
In 1927, Vickers merged with the Tyneside based engineering company Armstrong Whitworth, founded by W. G. Armstrong, to become Vickers-Armstrongs, Ltd. Armstrong Whitworth had developed along similar lines to Vickers, expanding into various military sectors and was notable for their artillery manufacture at Elswick and shipbuilding at a yard at High Walker on the River Tyne. Armstrongs shipbuilding interests became the "Naval Yard", those of Vickers on the west coast the "Naval Construction Yard". Armstrong Whitworth Aircraft was not absorbed by the new company. In 1928 the Aviation Department became Vickers Ltd and soon after acquired Supermarine, which became the "Supermarine Aviation Works Ltd". In 1938, both companies were re-organised as Vickers-Armstrongs Ltd, although the former Supermarine and Vickers works continued to brand their products under their former names. 1929 saw the merger of the acquired railway business with those of Cammell Laird to form Metropolitan Cammell Carriage and Wagon.
In 1960 the aircraft interests were merged with those of the Bristol, English Electric Company and Hunting Aircraft to form the British Aircraft Corporation. This was owned by English Electric and Bristol. BAC in turn owned 70% of Hunting; the Supermarine operation was closed in 1963 and the Vickers name for aircraft was dropped in 1965. Under the terms of the Aircraft and Shipbuilding Industries Act BAC was nationalised in 1977 to become part of the British Aerospace group, which exists today in the guise of BAE Systems; the Aircraft and Shipbuilding Industries Act led to the nationalisation of Vickers' shipbuilding division as part of British Shipbuilders. These had been renamed Vickers Armstrong Shipbuilders in 1955, changing again to Vickers Limited Shipbuilding Group in 1968; this division was privatised as Vickers Shipbuilding and Engineering Ltd in 1986 part of GEC's Marconi Marine. It remains in operation to this day as BAE Systems Submarine Solutions. With their steelworking operations nationalised into British Steel Corporation the remnants of Vickers became Vickers plc.
In 1986, Vickers acquired the armaments manufacturer Royal Ordnance Factory, which became Vickers Defence Systems. Other acquisitions included automotive engineers Cosworth in 1990, waterjet manufacturer Kamewa in 1986 and
A shell is a payload-carrying projectile that, as opposed to shot, contains an explosive or other filling, though modern usage sometimes includes large solid projectiles properly termed shot. Solid shot may contain a pyrotechnic compound if a spotting charge is used, it was called a "bombshell", but "shell" has come to be unambiguous in a military context. All explosive- and incendiary-filled projectiles for mortars, were called grenades, derived from the pomegranate, so called because the many-seeded fruit suggested the powder-filled, fragmenting bomb, or from the similarity of shape. Words cognate with grenade are still used for an artillery or mortar projectile in some European languages. Shells are large-caliber projectiles fired by artillery, combat vehicles, warships. Shells have the shape of a cylinder topped by an ogive-shaped nose for good aerodynamic performance with a tapering base, but some specialized types are quite different. Solid cannonballs did not need a fuse, but hollow munitions filled with something such as gunpowder to fragment the ball, needed a fuse, either impact or time.
Percussion fuses with a spherical projectile presented a challenge because there was no way of ensuring that the impact mechanism contacted the target. Therefore, shells needed a time fuse, ignited before or during firing and burned until the shell reached its target; the earliest record of shells being used in combat was by the Republic of Venice at Jadra in 1376. Shells with fuses were used at the 1421 siege of St Boniface in Corsica; these were two hollowed hemispheres of bronze held together by an iron hoop. Written evidence for early explosive shells in China appears in the early Ming Dynasty Chinese military manual Huolongjing, compiled by Jiao Yu and Liu Bowen sometime before the latter's death, a preface added by Jiao in 1412; as described in their book, these hollow, gunpowder-packed shells were made of cast iron. At least since the 16th century grenades made of ceramics or glass were in use in Central Europe. A hoard of several hundred ceramic grenades were discovered during building works in front of a bastion of the Bavarian city of Ingolstadt, Germany dated to the 17th century.
Lots of the grenades igniters. Most the grenades were intentionally dumped in the moat of the bastion before the year 1723. An early problem was that there was no means of measuring the time to detonation — reliable fuses did not yet exist and the burning time of the powder fuse was subject to considerable trial and error. Early powder burning fuses had to be loaded fuse down to be ignited by firing or a portfire put down the barrel to light the fuse. Other shells were wrapped in bitumen cloth, which would ignite during the firing and in turn ignite a powder fuse. Shells came into regular use in the 16th century, for example a 1543 English mortar shell was filled with'wildfire'. By the 18th century, it was known that the fuse toward the muzzle could be lit by the flash through the windage between the shell and the barrel. At about this time, shells began to be employed for horizontal fire from howitzers with a small propelling charge and, in 1779, experiments demonstrated that they could be used from guns with heavier charges.
The use of exploding shells from field artillery became commonplace from early in the 19th century. Until the mid 19th century, shells remained as simple exploding spheres that used gunpowder, set off by a slow burning fuse, they were made of cast iron, but bronze, lead and glass shell casings were experimented with. The word bomb encompassed them at the time, as heard in the lyrics of The Star-Spangled Banner, although today that sense of bomb is obsolete; the thickness of the metal body was about a sixth of their diameter and they were about two thirds the weight of solid shot of the same caliber. To ensure that shells were loaded with their fuses toward the muzzle, they were attached to wooden bottoms called sabots. In 1819, a committee of British artillery officers recognized that they were essential stores and in 1830 Britain standardized sabot thickness as a half inch; the sabot was intended to reduce jamming during loading. Despite the use of exploding shell, the use of smoothbore cannons firing spherical projectiles of shot remained the dominant artillery method until the 1850s.
The mid 19th century saw a revolution in artillery, with the introduction of the first practical rifled breech loading weapons. The new methods resulted in the reshaping of the spherical shell into its modern recognizable cylindro-conoidal form; this shape improved the in-flight stability of the projectile and meant that the primitive time fuzes could be replaced with the percussion fuze situated in the nose of the shell. The new shape meant that further, armor-piercing designs could be used. During the 20th Century, shells became streamlined. In World War I, ogives were two circular radius head - the curve was a segment of a circle having a radius of twice the shell caliber. After that war, ogive shapes became more elongated. From the 1960s, higher quality steels were introduced by some countries for their HE shells, this enabled thinner shell walls with less weight of metal and hence a greater weight of explosive. Ogives were further elongated to improve their ballistic performance. Advances in metallurgy in the industrial era allowed for the construction of rifled breech-loading guns that could fire at a much greater muzzle velocity.
After the British artillery was shown up in the Cri