National Republican., 1885-04-18
1.-THE race is not to the swift,
Nor the battle to the strong"

zion Of the genial host some scientific |
iaets, which are Of peculiar interest at
this time, when all the world is inter-
ested in the development of improve
ments in machinery and in the making
Of superior iron and steel. One, Of the
important features Of the engineers in
structive remarks has especial bearing
upon the construction ofthe United States
naval cruisers now being built, and the
completion of the dispatch boat Dolphin,
whose further trial has just been ordered
by the Secretary of tho Navy.
Having in mind the breaking Of the
Dolphin's steel shaft on her trial trip,
and remembering that thousands Of lives
have been imperiled and many destroyed
by reason of the loss Of propellng power
In steamers whose shafts broke at critical
moments, thus rendering the vessels help
less, and putting them Mt the mercy of
tempestuous winds and of powerful, rush
ing seas, The REPUBLICAN inquired
show do you account for the frequent
breaking Of steamboat shaftsT
Your question suggests consideration
Of great Importance, replied the engineer,
since, for many years past, steamboat
shafts and gun materials have been SO.
lected principally upon tho results Of
physical tests. Mr.. Longridge, mechan-
ical engineer Of experience in England,
referring to tho frequency Of tho break
ing of steel shafts on steamers, says:
Taking these instances of what happens
to Bessemer steel shafts, 1t seems very
doubtful whether tho material is one
which can yet be safely used"
The american Machinist says:
Mr. John Roach has received orders from
the Naval Department to substitute iron for
steel shafts IN all the vessels he has under con-
struction. This order appears to be the result
of the investigation as to the reliability of
steel shafts that was instituted after the accl.
dent to the shaft OF the Dolphin during her
trial trip. good many engineers will say
that the government has taken backward
step In abandoning steel for shafts, but we
think on the whole the action IL wise.
Another technical journal, The Age Of
6tceL, says:
Cases where breakage occurs under strains
that Steel article ought to have withstood
natural causes were the matter properly in.
yestigated but this has not been done. and so
long as mysterious" breakages are common,
the material will not have the entire conf.
dence OF the engineering world.
notice that distinguished engineer
stated lately to Senate committee which
had gun material under consideration
Tests OF small pieces in small machines show
strength OF metal which do not apply to large
forgings and large masses put together for
actual service. To illustrate this would men.
tion that some 6.inch steel bolts were tested
where in no instance did they reach a tensile
strength. when tested as a whole, OF 40 900
pounds TO the square inch, but repeated tests
OF small pieces cut from these same bolts sub
sequently bore loads Of never less than 30 0OO.
and most OF them from 10000 to 10000
pounds per square inch. This showed that
the bolt was under initial strains up to fully
know the strength Of that bolt, to test little
piece Of 1t was utterly deusiye. To know the
itrcngth you must test the whole piece.
In late report emansting from the
House committee on appropriations l
find this extraordinary statement:
The fact that no single rifle gun of large
caliber OF commensurate power for overcom-
ing the resstances of modern defenses possess
ing at the same time the requisite quality of
endurance has yet been produced or procured,
and the fact that no type OF such guns has yet
been adopted, points to the necessity of resort
ing TO new or modified methods not only of
construction, but rs well of enistng the ser
vices OF unhacRneyeu minds for the projection
OF armament, and perhaps more practical and
unprejudiced mechanical skill in Its consruc-
tion
Millions upon millions have been appropri.
ated and expended under the directions of our
ordnance authorities during the past quarter
ofa centiEy and the result has been a record
Of failures from beginning to end, and now,
when we are fully informed that no type even
% Of such arm armament ainf as Is required has been
that the kind of material TO be used In con-
Btructing cannon has not been determined
upon, we are asked to provide more extrava-
gantly for disbursements than ever before
since the close of the war
In 1865 Gen. Rodman, one OF our most dis.
tinguished ordnance officers, stated deliber-
ately TO u committee Of Congress: "My belief
is that no nation has yet decided definitely
upon which Is the best material for rifle gum" "
And ever since that time tho result of every
trial of guns which have burst, and of which
steel formed component and principal part
1t has been noted that 1t was the steel part of
the construction which most dlsastrously rup.
tured.
And in tho same report it is stated that
q prominent contractor engaged for years
in making guns of large caliber for the
government, said to an interviewer Of q
Boston journal:
A series of ominous incidents have occurred
In the gun tests. The more or less free open.
ing OF YIELDS in every gun tested, and the de-
mOralization Of the material ut the seat of the
charge the cracking from breech TO muzzle
ofthe steel tube and jacket in one of the early
converted guns, the blowing out OF
the tube of the l0.nch heavy muzzle.loading
rifle at the fourth or iiilh fire through the
opening of detective weld. 70 say
nothing oil the friction and the enormous
power required to tear of the muzzle of the
gun, the body of the gun sustaining no ap-
parent injury the discontinued proof of the
new l21'inch rifle after 30 rounds through
fear OF similar accident; the complete
cracking through necessitating early re-
pair OF the tube Of the ll.inch breech.
loading rihe near the seat of the
after few additional rounds, rupturing the
steel by blowing out the breech, but without
injury TO the cast from; the destruc-
ti0n a few days since Of the new S.inch con.
yerted breech-loader by rupturing at the third
fire the heavy steel jacket In its thickest part,
the gun body, rs usual, being unimpaired.
such a series OF accidents or failures cannot
certainly by any ingenuity or reasoning be In
lcEpreled a. complimentary to either the steel
9r'the wrought. iron, separately or in combi.
7atiOn.
In Holley's "Ordnance and Armor,"
shat distinguished au hor refers to dis
cuss,on before one of the learned societies
of England ON the subject of hidden hs.
sures, in the center of large masses of
wrought iron caused by contraction
from the center toward the circumfer-
ence as the mass cooled" in forging, and
it Is stated that
During the discussion some attempt having
been made TO rebut the authors assumption"
Rstatement that large ,orgings, weTc aiterall,
pret'S suunu alu trustworthy, he produced II
statement from the m9nagerol the Pcn.usuar
and Oriental steam Navigation Company, to
tho following effect During ten years, an
average OF more than one serious accident
had occurred irom the breaking of large for
gings, principally paddle aud screw shafts,
every three months TO one or to the other of
forty Zone ships. During the last five and a
half years down TO 1850 there were thirty
seven such accidents, or nearly one every two
mouths, on the same number OF ships, II was as.
Eumed that the cost Of these accidents, due To
the uns0undncss OF large forgings, would
average $4,000 each.
A few months ago when there seemed
10 be an epidemic of shaft breaking in
large Atlantic steamers, continued the
engineer host, l suggested to a prominent
journal, as a remedy Tor this class of ac-
cidents, that the stroke Of the engines of
steamships should be reduced to one'half
or less, thus doubling the number Of rovO-
Iutions. This, of course would reduce
the length of the cranks One-half or more,
anA thn Lnr.innal aIrain ON the shaIt in