The sun. [volume] (New York [N.Y.]) 1833-1916, 1892-12-21
NEW TRIUMPHs FOR AMERICAN
ARMOR.
The Harvey Plates OF Our Big Battle ships
Need Not Fear rerforntion.

Need Not Fear rerfofptl0n.
WASHINGTON. Dec. 2o.-The test Of a curved
Harvey plate last Saturday at Indian Head
proved, In its results. TO be OF most impor-
tant and surprising character. more SO. In fact.
than any similar trial that has ever taken
place in this country.
Commodore Folgcr. Chief Of the Bureau Of
Naval Ordnance. having received notice from
correspondent in London OF the results Of
destructive test OF a ten-inch Harvoyed plate
at Ochta. felt obliged to materially increase the
energy OF the attack originally proposed for
tho Indian Head plate.
The plate was curved with radius Of the
Tetrors turret. that being the shape and cur
Nature OF the only backing OF this nature
which is possessed at Indian Head. TWAS not
supported at tho ends in order to avoid
lateral spreading under impact. as would 10
the case with an cntire turret structure: nor
was tho backing itself Mt all satisfactory as re-
CARDS strength. having served for two tests OF
me Monterey's plates and one OF the Terrors.
IL mad. therefore. been considerably shattered
before Saturdays trial took place
The first round was ut the centre Of the
plato with n velocity OF 800 feet per second.
using an S-inch projectils Of 25O- pounds
weight. Of Holtser's manufacture Tho pene.
tration was but superficial. the projectile being
shattered TO- fragments. The plate was cracked.
right. indicating u lateral shock or vibration
due to imperfect contact with the backing and
to lack Of support at the sides. The crack was
also. OF course. due greatly to the increased
shock OF the excessive velocity.
Finding that tho penetration was practically
NIL Commodore Folger increased the velocity
for tho remaining three shots TO l.3OU-foot
seconds, which Is sufficient to completely uen-
citrate simple steel plato Is inches in thick
ness firmly botei to its 3D. incl! oak backing.
The results OF these shots was. us regards
cracking. the destruction Of the plate. one cor
nor OF it falling TO tho ground. No prolectile.
however. broke through the Harvey surface.
but each appeared rather to bend it inward.
The greatest depth attained was with Car
pcnter proIectie. the last fired. 1t may he
said incidentally that the largest fseHm ent OF
shell obtained WAS tho head OF this Carpen-
ter riolectilo. which was about twice tho
weighted any liolt2sr. fragment. and this. as
"ma II EoS ST. = an 81 tho superior
!, With regard to the cracking It is we'll to dis
tinguish between n crack which results from
which results from shock without pertoratlon.
IN ne former raso the projsctiie Is allowed to
there il Il displacement OF portion OF the
rlAte. and lightning is not supposed to strike
WEE Wee mat s nr pn a Dr .he sSE
l0o square feet or an area % by 10. should be
hioWed. harvey plated ship would APPEAR
TO 10 practically invulnerable. plates aad guns
being OF usual rrorortonnte size.
, The Impression left uron those present Mt
IN" test was that no ed velocity Of the
S-inch gun would have perforated this plate.
An inicfenc" can he fairy drawn also that this
same character Of result will prove to be the
case with thicker plates and larger guns.
II Will he apparent that since projectile.
.WhetheH large or sma'' J. can only ne tempered to
tn" same depth. there will be in the larger pro-
!ectlle much larger proportion Of distortihle
meta. Therefore. the question OF the break
smaller LroJeciiie should do better than the
iinrEer THUS equally favorable results may
lt.:nch plate. using II l0-inrh gun.
Tho theory tuk en- hY Commodore Folcer as
TO tho ACTION Of 'ho Harvey plate under, the
armOr plate. that the projecti1e shall impart to
tho molecules Of the plate At the points Of i'm
iart a veloclty IN separating them slightly
it enters. Now. il the tensile strength Of the
plate metal is Increased, as 8 effected by the
ienperinE process, and by the addition of car
bon. the time element needed to prod uce this
separation Is increased in length. Again. II
REQUIRES n certain me interval for the prolec
lilo to pass its length through the plate. from
complete reretrntio Remembering the
great mass OF the plate. it will be evident that
nIle. with tho increased resis ance. to effect
the separati"n Of tho plate metal in the time
required tor !ts own complete passage. and
the only possible result is its own fracture.
ton from this trial is thr necessity OF an in
crease in the calibi Of tho guns. since only
entire STRUCTURE. And this is precisely what
WAS pointed out in the recent annual report OF
tbs, chief Of the \ava! Ordnance Bureau.
Tho naNt effort to improve the armor will
he that of lesSennG crackin z on impact: and
there arc good reasons for surprising that
this may to SON" extent DO accomplished.