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Steam Carriages
with the indentations H, H, of nearly hemispherical
form, and with a larger flat circular indentation H .
Around the margin was formed a raised rim I. Nearly
one-half of the plate was laid over this mould, and by
hammering was caused to take the forms of the depressions
in the mould. Subsequently the other half of the
plate was treated in a similar manner, giving the result
shown in Fig. 4. The plate was then bent about its
FIC. 4. HANCOCK'S BOILER FOR STEAM CARRIAGES
middle so that it took the form, when riveted up at
the edges, shown in Fig. 1, the riveted edges not
being exposed to the fire, the rivets being confined to
the top and the two vertical sides. In Fig. 1 of group
Fig. 4 the riveted vertical seams are omitted. Each
chamber was thus of biscuit-bag form, and an alternate
mode of construction consisted in rivettne in between
the sides of the bent-up plate a piece of channel
iron, shown at J in Fig. 5. The circular indentations
are from 3 in. to 4 in. in diameter, and were made to
receive copper rings or gun metal K, Fig. 6, and a
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