The company experienced a boom in its business of making and selling incandescent gas mantles during World War 1. Gas mantles, the part of a gas lamp that glows, were made from Thorium, which was extracted from sands mined in Brazil. Before the war, Germany was the only country that produced Thorium from these sands, as pointed out in a letter to the Daily Express. With the war, imports from Germany ceased, and Thorium had to be bought from the US.
Robin Ltd. stated in a military service tribunal of 11th August 1916 that:
owing to the import of German mantles being stopped since the war their business had increased enormously, and they now employed 500 hands.
Maps are reproduced with the permission of the National Library of Scotland.