GERMAN INGENUITY.

Press, Volume LIV, Issue 16167, 22 March 1918, Page 2

GERMAN INGENUITY.

SEXTANT MADE ON MOTCIHI

ISLAND. Au interesting exhibit which has just been rceoired at the Dominion Aluseum is the sextant manufactured by the German prisoners of war on ]\Jotuihi and used by ihem in their dash for liberty from the island (.says the "Wellington "Post"). One would naturally suppose that an instrument constructed under su:'h conditions and Avitli the help of very limited appliances would be at best a rough-and-ready makeshift, but the sextant has been construetod with painstaking attent on to detail, and the workmanship almost throughout is well finished. which seems to point to the lacb that the sextant was probably the result of an ingenious prisoner's hobby rather than an instrument intended for a planned escape, and that it was not built for von Luckner's exploit is borne out by the initials "W. v. Z., 191G, N.Z., ' engraved on the arc or limb. Tho bronze frame, of 8} inches radius, is in cast brass, which suggests that help was obtained from a sympathiser who had access to a fairly elaborate workshop, as it would be difficult to mako such a casting on the island. This further suggests a hobby, for if a. fairly bulky frame c-ould have been smuggled' in, it would havo been not vt-ry much more difficult to smuggle in a complete instrument, in sections, at any rate. . The arc is divided surprisingly accurately, considering that it was don© without mechanical aids, to read to onohalf of a degree, and a screw Vernier, a refinement not found in the older types of sextant, has been addod to give minute readings. This finer adjustment, however, cannot greatly add to the accuracy of the instrument, for as the half-degree divisions on the arc ore inaccurate, the Vernier reading would, if anything, increase tho error. Alany .sextants have "constant" errors, which can be allowed for, but the errors in this instrument vary at different angles, and consequently tho instrument could be depended on only to give a fair approxi- j mation of latitude. • Further refinements arc provided in adjustments to the horizon-glass and movable mirror, k small lens, and a ground-glass shade to aid in tho reading of the Vernier scale, and three ruby darkening glasses to counter the glare of the sun. The only part which appears to havo been hastily constructed is the eyepiece—the cylinder of the pressure pump of a primus' lamp adapted to a use its original makers never intended. Various parts of a primus lamp have also been used for some of the smaller parts of the instrument. Tho maker has closely followed stereotyped lines even to the method by which the instrument is clamped in place in its box, and, accurate or not, the result of a hobby or a well-laid plan, it must have been with pardonable pride that the builder gilded his initials in large letters on the lid of the case, for the instrument is certainly a marvel of ingenuity. ■