NOTES AND COMMENTS.

New Zealand Herald, Volume LII, Issue 16032, 25 September 1915, Page 6

NOTES AND COMMENTS.

THE ZEPPELIN IX WAR. The Germans would fain persuade themselves that the Zeppelin, the solitary survivor of the rigid system of construction in the lighter-than-air machines, is without defect but this much-boasted creation is not without patent drawbacks. Its field of operation, as the designer himself admits, is limited to an elevation of 5000 ft, and at this moderate altitude is liable to be attacked by the nimble aeroplane On the other hand, the Zeppelin can rise about 3500 ft in three minutes, a rate far in excess of the ascensional speed of its antagonist, that climbs by a succession of spirals. Since the weight of equipment is a minor consideration, its engines can be heavier and made practically noiseless, an improvement that should give the huge monster a great advantage in night operations. The Zeppelin can hover almost stationary over a given spot for the purpose of reconnaissance, and make more exact determination of the disposition of an enemy's force than can the observer in th aeroplane. At the same time, its bulk offers a magnificent and steady target for the average gunner, who, equipped with the ingenious devices that experience has suggested, can hardly fail to hit- Against this risk must be placed the advantage that the Zeppelin, in common with all dirigibles of large size, can throw heavier bombs, and charged with greater quantities of high explosives and shrapnel, than those which can be hurled from the heavier-than-air machines; Possibly the statement that a Zeppelin can throw or drop a bomb a ton in weight is an exaggeration, since the detachment of such a weight would disturb the equilibrium, and give to the dirigible such an upward thrust that it is doubtful if the nicelyadjusted arrangement for controlling the movement in the vertical plane would be able to counteract the vertical acceleration. The journal Engineering is disposed to discount this supposed advantage of heavy bombs, because up to the present the damage wrought by Zeppelin air-craft has, from a military point of view, been comparatively insignificant. i

MERCHANT SHIPBUILDING TRADE The concentration of much available labour from the shipbuilding yards upon the construction of naval ships and war munitions., says a recent issue of Engineering, has necessarily influenced the volume of work done on merchant ships. Lloyd's quarterly return, which has just been issued, is almost anomalous in respect that little progress is being made with a great number of the ships under construction; indeed, on some of them no work has been done for many months past. The vessels launched during the June quarter number only 75, and make up only 148,214 tons, which is at the rate of only 590,000 tons per annum, whereas the usual output is thr*3 times that amount. At the same time the number of vessels commenced only numbered 84, and measured 172,325 gross tons. But, as a matter of fact, this state of affairs is not because there is any Wk of demand for new tonnage, but rather because shipbuilding firms are not permitted to undertake merchant work in the present crisis. The total number of vessels under construction in July was 442, of 1,506,925 tons, which is 81,000 tons less than three months ago, and about 215,000 tons less than twelve months ago The diminution in the tonnage as compared with March last was applicable to all districts except Hartlepool. There the increase was 10,000 tons, the total merchant vessels building being 15, of 71,550 tons. At Belfast there were 24 vessels on the stocks, the tonnage being 260,700— 20.000 tons less than three months ago. At Glasgow 82 vessels, of 553,923 tons, were under construction, the decrease being 17,600 tons. The reduction at Greenock was only 8900 tons, as there were 'here 46 vessels, of 209,004 tens, in progress. On the Tees I the decrease was only 3800 tons, the number of vessels in progress being 31, of 83,165 tons On the Tyne the decrease [ was 30.000 tons, the number of vessels ' being 62 and the tonnage 27,854. At' Sunderland there were 43 vessels underwayg making 162,836 tons.