This is a really good example of a very early Vapalux E41, probably made within months of production starting at Halifax. Items of note are the red catalin control cock knob, used on the first lamps. Early red coloured washers. Patent pending on the globe frame. Vapalux marked globe with lighting hole and registered patent stamped in the gallery. Willis and Bates Ltd shown on the manometer...Willis and Bates Ltd became Vapalux Ltd in July 1941. Manometers after that date don't carry a makers name.