A boiler is made of a copper plate 2.4 mm thick with an inside coating of a 0.2 mm thick layer of tin. The surface area exposed to gases at 700°C is 400cm2 . The maximum amount of steam that could be generated per hour at atmospheric pressure is(Kcu=0.9cal/cm−s−0&ktin =0.15cal/cm−s−0C and Lsteam =540cal/g)