mm rifle to use the new powder in 1886. That was 12 years before the Spanish-American War. The development of smokeless powder was part of a chemical revolution that began in the mid-19th century and included, among other things, dyes from coal tar, anaesthetics, aspirin, heroin, and dynamite.
Dynamite, patented in 1866, was made in many varieties, some, such as gelatine dynamite, extremely powerful, all extremely sensitive. Dynamite is based on an early explosive, nitroglycerin, which is too sensitive for almost any use.
Alfred Nobel first mixed nitroglycerin with an absorbent earth to desensitize it.
He later mixed it with other explosives, such as ammonium nitrate, potassium chlorate, or nitro cotton to obtain a very powerful explosive that was still safe to handle (with care). Gun-makers tried to use dynamite for a shell filling (Chapter 19) but it proved to be too dangerous. It could never be used as a propellant.
It is what is called a high explosive: one that almost instantly decomposes into a huge amount of gas, whether it is confined or unconfined. This reaction is called detonation. Propellants, like black powder or smokeless powder, decompose more slowly. They are said to burn, although smokeless powder, if confined tightly enough, may also detonate.
Nitroglycerin is a compound of nitric acid and glycerin. About the time Nobel was experimenting with nitroglycerin, other chemists were nitrating other organic substances. Nitrating cotton a little produced nitro cotton, a component of gelatine dynamite. Nitrating it a lot produced guncotton, a rather sensitive explosive once used as a filling for torpedoes, but now an ingredient of smokeless powder.
TNT, or trinitrotoluene, became extremely popular as a filling for shells, torpedoes, aerial bombs, and hand grenades because it combines great power with a reasonable lack of sensitivity. It was widely used in both world wars.
Many new high explosives have been developed since the war. They are never used as propellants — the many varieties of smokeless powder handle that chore — but they have completely replaced “low explosives,” such as black powder as fillings for shells and bombs. When a black powder shell exploded, it burst into a few large pieces, none with enough velocity to carry far. High explosives shatter a shell into thousands of tiny, sharp metal fragments traveling at high velocity. These fragments are so effective against personnel that they have completely replaced shrapnel. Against solid objects — forts, tanks, ships, and so on — high explosives are infinitely more effective than black powder. And they make possible the shaped charge.
Chapter 31
Big Bertha and Her Cousins: The Super Siege Guns
Belgium, sandwiched between France and Germany, knew it occupied dangerous real estate. Its territory had been a battleground since Roman times, and now it occupied the space between two large and unfriendly powers — unfriendly to each other, that is, and oblivious to the rights of small neutrals. Of the two, the German Empire, born in 1870 and pursuing an aggressive foreign policy ever since, seemed the greatest danger. The kaiser had been bullying old King Leopold II and his nephew, King Albert I. “You will be either with us or against us,” he told old Leopold. A German officer told Albert’s military attache in 1913 that war was inevitable and that it was “imperative for the weak to side with the strong.”
To discourage an invasion, the Belgians built what some authorities said were the strongest forts in Europe around such vulnerable cities as Liege and Namur. The forts circled each city and were about 2 or 3 miles apart. They were mostly underground, with armor cupolas that could be raised above the surface to fire. Each fort was surrounded by a triangular ditch 30 feet deep. Above each fort was a revolving searchlight that could be lowered beneath the surface. The ring of forts at each city had some 400 guns, not counting the numerous machine guns. And hidden by the turf that covered the forts were thick walls and ceilings of concrete. They were guaranteed to withstand anything that could be hurled from a 210 mm (8.4 inch) gun. The 210 mm was the heaviest in any army, and when the forts were built — between 1888 and 1892 — it was believed to be the heaviest gun that could be used. Years of experience had shown soldiers that there was a practical limit to how much weight horses could pull.
Back then, soldiers had not thought much about the limits of internal combustion engines.
At first, the forts at Liege did hold up the Germans. A staff officer named Erich Ludendorff went up to the front to reconnoiter, discovered an undefended gap in the Belgian forces surrounding Liege, and led German troops into the city. Ludendorff captured the city — the first step on a path that would lead to his becoming German commander-in-chief. But the forts were still in Belgian hands.
But Germany had an answer. The Skoda plant of its ally, Austria-Hungary, had developed a 305 mm (12.2 inch) howitzer that could be disassembled into three pieces and towed by gasoline-powered tractors. When they arrived at their destination, they could be reassembled and ready to fire in 40 minutes.
The Austrians loaned several of these guns to Germany. Meanwhile, Krupp, Germany’s premier gun-maker, had been developing a true monster — 420 mm (16.8 inch) howitzer. The gun, nicknamed Big Bertha after the wife of Krupp’s proprietor, was hardly as mobile as the Skoda gun. The first version had to be moved by rail, and tracks had to be laid to its firing position. Krupp’s people worked frantically to develop a version that could be towed over roads. On August 12, 1914, nine days after German troops confront Liege, the first Big Bertha arrived. The bombardment of the Belgian forts by the 305 mm Skodas and the 420 mm Krupp began. The huge guns pounded the forts to pieces. By August 16, they had all the forts. The Germans then moved their monster guns to Namur and destroyed those forts.
The Skoda mortars enjoyed equal success on the Eastern Front, where they pulverized Russian-held forts and field fortifications. On the Western Front, though, the super guns made no other noteworthy appearance until 1918. At that time, March 23, 1918, a 210 mm shell burst in the middle of Paris.
Ludendorff’s last offensive, intended to end the war before the United States could land a substantial number of troops, had begun on March 21, but the Germans were far from Paris. That shell burst and the many that followed it were supposedly intended to break the French morale. Actually, it seems more likely that it was a project undertaken by German artillery experts to see if it could be done. Officially dubbed Wilhelm Geschutz or William’s gun, the “Paris gun,” also called “Long Max,” was the most complex piece of ordnance ever designed up to that time. It was firing on Paris from 74 miles away — about three times as far as the largest conventional naval gun, a 16 inch rifle, could shoot.
To build it, the German engineers took the barrel of a 381 mm (15 inch) naval gun, 55 feet, 10 inches long, reamed it out and inserted a 210 mm tube. That second barrel increased the length of the gun by 36 feet, 11 inches, making the finished barrel almost 93 feet long. To that, they added an unrifled tube to the end of the gun, making the whole assembly 112 feet long. It weighed 138 tons.
To take advantage of this enormous length, the German ballisticians devised a special slow-burning smokeless powder. This was packed into a chamber 15 feet, five inches long. The heat generated by this giant powder charge and the tremendous velocity of the shell, would wear out the barrel rapidly. The gun would have to be rebored every 65 rounds. The weight of each shell, from the first to the 65th was altered to make up for the loss in velocity and accuracy.
The long, long barrel was braced with a cable truss to keep it from sagging.
To move it, the gun was disassembled as far a possible, loaded on special railroad cars, and hauled to its firing position, a spot in the forest to which track had been laid. There were at least two of these guns, each emplaced on a massive concrete foundation. At 7:15 a.m., the Germans fired the first shell.
Three minutes later, the shell landed in Paris. At that range, the guns needed a target as big as a city. The rotation of the earth, air currents, and even air temperatures at various heights up to an altitude of 23 miles had to be considered. “William’s Guns” kept firing from March 23rd until August 9th. They fired 367 shells and killed 256 people, 90 of them when a single shell fell into a crowded church on Good Friday. As a weapon, the Paris guns were useless, wasteful, and cruel. They did, however, help develop techniques that would be used on other giant guns in
