he
furnace a 90 ton ingot for a large gun for an armor-clad vessel. The
piece is carried by a steam crane of 140 tons power, and the men
grouped at the maneuvering levers are directing this incandescent mass
under the power hammer which is to shape it. This hammer, whose huge
dimensions allow it to take in the object treated, is one of the
largest in existence. Its striking mass is capable of reaching 100
tons, and the height of the fall is 16 ft. To the left of the hammer
is seen a workman getting ready to set it in motion. It takes but one
man to maneuver this apparatus, and this is one of the characteristic
features of its construction.

The beginning of this hammer's operation, as well as the operations of
the forge itself, which contains three other hammers of less power,
dates back to 1879. It is with this great hammer that the largest
cannons of the naval artillery--those of 16 inches--have been made
(almost all of which have been manufactured at St. Chamond), and
those, too, of 14, 13, and 12 inches. This is the hammer, too, that, a
few months ago, was the first to be set at work on the huge 13 in.
guns of new model, whose length is no less than 52 ft. in the rough.

Let us add a few more figures to this account in order to emphasize
the importance of the installations which Mr. Layraud's picture
recalls, and which our great French industry has not hesitated to
establish, notwithstanding the great outlay that they necessitated.
This huge hammer required foundations extending to a depth of 32 ft.,
and the amount of metal used in its construction was 2,640,000 pounds.
The cost of establishing the works with all the apparatus contained
therein was $400,000.--_Le Monde Illustre._

* * * * *

FORGING A PROPELLER SHAFT.

During the recent visit of the Shah of Persia to England, he visited,
among other places, the great works of John Brown & Co., at Sheffield,
and witnessed the pressing of a propeller shaft for one of the large
ocean steamships. The operation is admirably illustrated in our
engraving, for which we are indebted to the _Illustrated London News_.

[Illustration: PROPELLER SHAFT BEING PRESSED AT MESSRS. JOHN BROWN &
CO.'S WORKS, SHEFFIELD.]

* * * * *

CRANK AND SCREW SHAFTS OF THE MERCANTILE MARINE.[1]

By G. W. MANUEL.

[Footnote 1: A paper read before the Institute of Marine
Engineers, Stratford, 1889.]