galvanized iron rests directly upon the binding-rafters, the upper parts
of which are covered with wood for the attachment of the corrugated
metal. The spacing of these rafters is calculated according to the
length of the sheets of corrugated iron, thus dispensing with the use of
ordinary rafters, and making a roof which is at once very light and very
durable, and consequently very economical. Rain falling on the roof
flows into leaden gutters, from whence it is carried by leaders into a
subterranean drain. The vertical walls of the structure are likewise of
corrugated iron, and the general aspect of the building is very original
and very satisfactory.

_The 80 Ton Hammer_--The three hammers, notwithstanding their difference
in power, present similar arrangements, and scarcely vary except in
dimensions. We shall confine ourselves here to a description of the 80
ton apparatus. This consists, in addition to the hammer, properly so
called, of three cranes of 120 tons each, serving to maneuver the pieces
to be forged, and of a fourth of 75 tons for maneuvering the working
implements. These four cranes are arranged symmetrically around the
hammer, and are supported at their upper extremity by metallic stays.
Besides the foregoing there are three gas furnaces for heating the
ingots. Figs. 1, 2, and 3 show the general arrangement of the apparatus.

_Foundations of the Hammer and Composition of the Anvil-Bed_--To obtain
a foundation for the hammer an excavation was made to a depth of 26 feet
until a bed of solid rock was reached, and upon this there was then
spread a thick layer of beton, and upon this again there was placed a
bed of dressed stones in the part that was to receive the anvil-stock
and hammer.

On this base of dressed stones there was placed a bed formed of logs