 On July 30, 1915, it was first used in a concerted action, against British trenches at Hooge, where the lines were apart—even there, the casualties were caused mainly by soldiers being flushed into the open and then shot rather than from the fire itself.After two days of fighting the British had suffered casualties of 31 officers and 751 other ranks.The success of the attack prompted the German Army to adopt the device on all fronts.