CrreípiwküCi' c,f Mie N. V. Timan. Oi,d 1'oiNT Oomfobt, Va., Aug.29. The ciiriosity of the artillory oCBcors and of the gueats at Old Point wus grátified yeaterday by tho firat Bring of the groat "Floyd" gun of wbiuh 1 have before spoken, Tho first shell, weighing 360 pounds, was thrown fifteen huudred and forty yards at au angle of five dogree?, and, striking tho sand, bounced ssovon hundrod and fiity yards further. The charge of powdor was twenty pounds. The seoond sholl, weighing 328 ponnds, was thrown something npward oí' four milos on the water, at au angle oí forty degrees, and with a charge of twonty-live pound of powder. i'he powdur wiih which thia gun is (red is in grains of about ono ir.ch cubo. Tho report is ïioó so loud as tb at made by tho tunineh guns on the rainpat'U, but the wbistling oí the abel] through the air i.s tenifiü. The sholl thrown upon thu wiitui' WH8 forty-two seconds in tho air beloro striking. Tho "l'loyd'1 gun i.s prohbuncud a ruocoss, and there soeir.s to bo no doubt it will reach a rango cf pix or ejght miles. It weigha 4(J,OO'J Ibs., and cost in it.i casting $10,000. Jiith the i rojector (Gapt. Jiodinan), and tho propn'etor of tho l'iltöburg imiiutiy plr Kn:i]ip) vvhere the cannoii was ca.t, are hyi-o suporintending the firing of thia monster gun. Tlio experimvaU are conducted by Capt. Dyer, ei' life ürduanco Department - ono if tho most experienced and sciontific oiEeers belonging to tho anny, aud tiiit.o asan acoomplisiiod gentlemen as hc is au ablo officsr, Iiieut. Bagga, a prom.isipg young officer, is preparing to test the "Floyd" niiclis by moans of an ingenious telegrapbic arrangement. As the shell pa ses frofi) tho unouth of tho cannon il euU a vvire, whicii produces acurron, and sots in motion a pendulum at an instrument socureiy arrangod under the caseinato oí tho fort. Tho targut, plí.ued at a íixed distance, is coveres with a perica ot wires, oae of whicd must be ent by the sbellwhefl itslrikth the target. The moment tho second wiro is out the eunx'iit i.s braken, and the pendulum instautly stops, marking the pace through wh.oii it had passed iluring the time the sliell was passing between the tivo wirès.