Fig. 1 is a cross section and Fig. 2 a longitudinal section of a suitable furnace to be used when making railway wagon springs. A shows the flrehole, B the blast inlets, and C the ch im-bers for the spring plates. The products of combustion pass through flues in the bottom of the third chamber, and thence under the floor to a stack in some convenient position. The furnace should be built of brick and lined with firebrick, iron doors being fitted in the usual manner to open with chains, pulleys, and weights or levers. The stays are of cast iron.