Inscribed on the base with a GB patent number of 1392848, filed in 1972 and published in 1975, the Birmingham coppersmiths originated in the 19th century (as E.V. Wilkes) and went out of business in the early 1980’s. The stove’s a nickel-plated Optimus 5S, older than the kettle (burner older still). The patent relates to a quite precise set of measurements for the quick-boil skirt/shroud, the rectangular openings in it and the dimensions of the wire coil incorporated in the skirt/shroud and base rim. The purpose of the design is described in the patent: I recently posted details HERE of a quick-boil kettle from the 1930’s, so well before the time when natural gas was supplied to British homes. It’s interesting to compare the two kettles and in particular their quick-boil coils and skirt/shroud configuration, together with the vents in them. The tightly-packed coils of the older kettle (more copper) no doubt explains to a large extent the greater weight of the latter of 300g (2/3 of a pound). The chrome-on-copper kettle has adopted the spout-orientated direction arrow on the lid of the 30’s kettle to place the lid vents to the rear to allow steam to escape but not spill water when the kettles are tipped for pouring. John
