, 1900-06-09

cess, which consisted of hardening the
face of the plate, was a secret, and no
one was allowed in the building except
the officer in charge and a few work
men. The admiral continues:
The plate, having been placed in
the furnace, was covered with a lay
err of ~carbonizing material (probably
a mixture of animal and vegetable
charcoaD about a foot thick, over
exclude the flame and air from the
plate. The doors of the furnace hav-
ing been bricked up, the fires under
meath were started and it was brought
up to a high heat and so maintained
for about 100 hours. Arrangements
lad been made for Withdrawing the
plate from the furnace and for sprink-
ling it with cold water from a large
trough with a perforated bottom, sus-
pended overhead at a height of some
ten feet.
When the time arrived for taking
the plate from the furnace the brick
work wa knocked away and a yoke of
oxen were hitched to a chain made fast
to the plate. The Ken tugged in vain
and a second yoke was brought into
requisition, but still the plate remained
immovable, the high prolonged heat
having virtrified the sand, tiles and
brick into a solid mass. A large force
of men was brought up to aid in the
work and with the assistance of tackles
and levers the plate was, after five
hours labor, hauled out of the furnace
under the sprinkling trough.
Naturally it had lost a good deal of
its heat and was a dull cherry red
when the water was applied, which
formed Kissing, jets of steam as it fell
on the hot plate, which, to the dismay
of the spectators, began to curl up like
a huge saucer as its upper surface con-
tracted under the influence of the chill.
The spraying was continued until the
plate was cooled to a black heat, when
II lttoNtlth = 5hdpt u Soiht NANNhl.
but the warping was then regarded as
q serious objection to the process, but
in future plates this was overcome by
%sprinkling on both sides and in the
regular furnaces the plates were there
after laid on iron cars and could thus
, be quickly withdrawn"
This plate showed remarkable powers
Of resistance, and the navy depart
ment conducted a series of experiments
which resulted in proving the super
iority Of the Harvey plate. Admiral
O'Neil gives much of the credit of
bringing it forward to Captain Will
, lam NJ. Folger, United States navy, who
carried out the tests.
The Harvey plate kept its place in
the front rank until 1895, when the
Krupp process, a modification Of the
Harvey process, was introduced. Eng
land was quick to recognize the value
of the improvements and acquired the
rights thereto in 1895. In 1898 the
|, rights were acquired in this country.
| l ne HTSt tests were Oh plates mdue ny
/, the Carnegie company and the Bethle-
hem company in October, 1898, when
the excellence of the process was dem
onstrated. Krupp armor differs from
t Harvey armor in the character of the
alloy and in the method Of its treat
ment.
, The manufacture of modern armor
, plate for service use began in this
country in 1886. The total amount OF
:, armor furnished when present o n
; tracts are completed will be 3S5,773
tons. At the present time there is re-
quired for three battleships Of the
Maine class 1850 tons. The depart
ment desires to use armor made by
Krupp's new process for these and for
other vessels authorized but not yet
contracted for, for which about $4,000
tons more will be required.