SHARPSHOOTING AT SEA.

Auckland Star, Volume XXIX, Issue 178, 30 July 1898, Page 4 (Supplement)

SHARPSHOOTING AT SEA.

The accuracy of ft*Ki«m rifled guns is one of the wonders of engineering. Two experimental shots fired a few years ago at the same elevation from the same gun fell within 30 yards of each other, after traversing a distance .of 12 miles. If a modern rifle is laid upon the target, with proper elevation and allowance for ■windage, it is safe to say the shot will find the mark. The correct elevation ot fee gun can only be determined if the . distance of the target is known, and the _£__t determination of the distance ot a moving object is a problem that has worried the gunner ever since the day when round shot was first thrown from the sides of the wooden fighting ship In the early days, says the 'Scientific American,' the determination of the range ■was a matter of guesswork. The gunner assumed a distance, elevated his gun accordingly, and watched the course ot the- shot. If it fall short he increased the elevation, and if it passed over he decreased it. This was all very well in a day when the guns were too feeble to do much execution except at close range, and a few dozen shots thrown away made little impression upon a ship's magazines. With the advent of modern ordnance, however, with the 60 ton guns and costly charges, the necessity of accurate fire became imperative, and ordnance experts set. about devising some scientific method of finding the range at sea. The earliest and best known device of the kind was the inception of Lieutenant Fiske, of the Unit- | ed States Navy, which has been in-j stalled on many of our ships, and is widely in use in the various navies of ■the' world. The Fiske range finder ip, pased upon the well known principles of land surveying with the transit and engineer's chain. If a surveying party come to a broad river whose width has to be determined, a base lie is measured along the bank, and the angles which this line makes with a mark onthe opposite bank are measured by the transit. Then, knowing: the length of the base line and the two angles, the distance across the river can be determined by trigonometry. Applying this to the range finder, a base line is carefully measured between two points near opposite ends of the ship, and over each point a lange finder, answering to the engineer's transit, is permanently set up. If the telescopes of the two finders are simultaneously converged upon the same point on a distant object, ship, fortress, <or city, the observers will be in posses-s-.on of the • trigonometrical data necessary to compute the distance, namely the l«as& and the two base angles. .In the din "wry, and slaughter of a sea fight, however, it would be difficult to make the necessary calculations, as the distance the ships, and therefore the J-iyf ansles' kfeep changing, and in Sift!, make the determination of the pfi e hua? t?l?atlc' Lieuten*nt Fiske WW* telesc °Pc in the circuit of a *Seof° ne,bridge-and caused »eir s? oo^c o tsiton on t,to re?r the aistancs " * delicate^, graduated scale of »ow ne« ss^ Van°meter- AU that wa* « the 5 L f°r the observera ..'■;-■■ «wss hairs ot tho + n(? ers to kee P the *«ne point of the fi^ elescope u P°n the e,"t translated aL P' t and the electric ff into distances ll were- the an- :.;;.-. -'^movements nf and "corded them by I abated into huna dr "| edle °ver an arc £ yards, one c_ %^ s and thousands in t^c^, 86 galvanometers -;•;. M pacta; ot- .theStoS £w.er and one ncipal Sun stations.