Shells, chemical first fired

Beginning in the summer of 1915, chemicals were loaded into artillery shell, first of the light calibers, and then of hcaticr calil ers, 8. the war progressed. By 1917, artillery of all calil>ers were firing chemical shell although many of the heavier shell were unsuitable for cliemical dissemination. 

The process for making calcium oxide is believed to be one of the first chemical reactions known to humans, dating back to prehistoric times. When limestone (calcium carbonate CaC03) is heated, carbon dioxide (C02) is driven off, leaving calcium oxide behind. The reaction was probably discovered very early in human history because limestone is a common, readily available material in the form of chalk and sea shells, and the amount of heat needed to produce the reaction can easily be produced in a simple wood fire. A more efficient method for carrying out the reaction is to heat the limestone in a kiln (oven) at temperatures of 5oo°C to ° (900°F to i,6oo°F), resulting in a more complete conversion of calcium carbonate to calcium oxide. This method is still used today for the commercial preparation of calcium oxide. 

On 27 October 1914, the Germans fired 3,000 of these projectiles at the British near Neuve-Chapelle, but with no visible effects. The explosive aspect of the shells destroyed the chemical aspect. In fact, the British were apparently unaware that they were the victims of the first large-scale chemical projectile attack. 

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