Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1848-12-09
THE WASHINGTON ARSENAL.-CAPTAIN
MORDECATS PENDULUMS.

Perhaps in part Of the United States many OBJ
ects Of scientific interest be found Washington and
ts vicinity One who has only recently become resident
here struck with this, while visiting the United States
Arsenal, day two ago, for the FIRST time Among the
wonders Of this place his attention particularly attracted
by the apparatus employed for ascersnng velocity Of
cannonbal and the force Of gunpowder The whole pro-
him, and will probably be the msoity
Of the readers Of this paper.
On entering the yard his attention attracted by
structures in the form of Egyptian obeks, which might
models Of the the fir-famed temple Of Luxor.
Having made inquiries in regard their object, he
informed that within them be found the balisc and
gun peneuums which employed by the Government, for
experiments sunney. He had the pleasure Of wit
Messing any pemens HIMSELF but the apparatus po
tey exhibited him by OF the officers in command,
CLicut RISGsoLn.)
One Of the problems be solved by hes penduums Is the
velocity Of the cannon-ba and the ingenious machines by
which ibis determined made tho plan Of French
invention, which, however, has been greatly improved upon
by Cspt MorpEcAI, Of the Ordnance Department The
bclc pendulum, which employed FOR determining the
ociy Of ball distance from the mouth al the cannon,
is Of iron, in tie form Of hollow fusum Of
with hemsphercal bottom, and this being filled with sand
receive the ball. ard covered at the mouth with sheet Of lead,
the point where the ball strikes thus distinctly marked by
mpineing Of tho ball gives motion. and the afterwards
swing together body, but vita velocity slow that
may accurately measured anl therefore, BY knowing
weight Of the pendulum and the ball. and the velocity
given to the compound, the original velocity Of the ball may
lie asceriaiDed.
The general arrangement Of the gun pendulum is similar
to that Of the balc pendulum and the space which sepa
rates them fifty five feet The method Of determining the
velocity of tho ball issues from Che no,t Is a.
follows The gun being dclicsey suspended TO form,
as werc the bob Of immense pendulum, when the BALI
is fred the Of reco accurately noted, and from this tho
velocity VITA which the gon backward IS readily dis
covered end since the bail forward With the same
that the recoil, the velocity OF the former
viii be much greater its weight less than that Of the
latter.
The suspension frames Of these pendulums sfe made OF
wrought icn and sufficiently large and strong 10 hold with
pede, ease FOUNDER wi fired with charge Of
quarter or onethd weight OF The sho: The shafts
TO which the attached terminate al each end on
knife edges, which supported ny massive stone Tfefs
The vibrations Of the rendulnms measured hrass
placed mn r the a,is of TIE block and gun which are
supported by iron chairs set IN stone posts Upou arcs
are slides Of brpss which held any POINT by the pres
sure Of ght springs these slides pushed tack along the
arc Inv the c, OF the cannon and thus marx the precise
extent Of the ssog This being known, the velocity with
which the begins cco u be readily determined,
i being the that which body would have in falling
from perpendicular height through which the csunon
taised IN .ts passage UP the
10 looking the tables Of results obtained by Captain
MoRpEcar, we notice The following fact in gsd the thr
ytSo pound shot The velocity varies from Twelve
hundred feet per second making average or about
fifteen hurded feet per sccond nearly twenty miles per
minute The velocity though great is almost rest in
pa-on with the speed Of The electric along the ele-
graphic wc the velocity Of the latter being nearly two hun
cred thousand miles per secon To thoee Of our reade,s
Who would wish become fully acquainted with he results
Of The extended series Of experiments which have been made
tho Arsenal the velocity Of bassnd the force and qp-
ty Of powder, tho perusa of the Official Report Of Captain
Mo9D1cAr on this subject may be reoonmended