Hugo Stoltzenberg for the first time on the Western Front. The first gas attack occurred against Canadian soldiers and also against a force of mostly colonial soldiers from French Africa known as French colonial troops. The gas used was Chlorine gas. Mustard gas, also called Yperite from the name of this city, was also used for the first time near Ypres in the autumn of 1917. Prior to that, Stoltzenberg had injured his eye in an incident involving a chlorine gas cylinder which exploded and blinded him in the left eye. After the end of World War I, Stoltzenberg participated in clearing
German Type IXA submarine The first U-boat to be laid down in the Bremen ship yards was "U-37", whose keel was laid down on 15 March 1937. The last U-boat to be laid down was , whose construction began on 15 September 1937. By November 1939, all eight submarines had been fully constructed and commissioned into the "Kriegsmarine". The Type IXA submarines were the first German submarines to have a double hull. This allowed for a greater chance of survival in the event of an attack and gave them better seaworthiness on the surface. The Type IXA submarines had a test depth of .