A CRACK IN THE 80-TON GUN.

New Zealand Times, Volume XXXII, Issue 4983, 13 March 1877, Page 3

A CRACK IN THE 80-TON GUN.

Just as the experiments with the 80-ton gun were on the eve of completion a vexatious mishap has occurred, serious enough in itself, but not thought of sufficient importance to prevent the conclusion of the programme. The holes pierced through the body of the gun for the insertion of the pressure-gauges have been calculated to weaken it in no slight degree, and it should be recorded to the credit ; of the great weapon that it has fired 166 rounds, in which! it has burnt 23 tons of pow-’ der, and discharged 130 tons of shot. .To this most be added the fact that the charges fired ;in the latter stages" of the trials have' bee* much -heavier than: was contemplated in the design of the gnn, and, that the closer confihe- : ment of the powder gases secured by, the gascheck has also, to some extent, added to tbe work imposed upon, the great, cannon. Tbs Authorities, therefore, have regarded, and still I regard with satisfaction the unimpaired j condition of the main structure, while they iadmit, as they have always admitted, :that the steel tube or lining of the igun is its one weak and unreliable part. In this steel tube a crack has been discovered. Guttapercha impressions of the bore have been taken at various stages, and the examination mode in this way, preparatory to the renewed trials arranged to be made, revealed the presence of tbe incipient fracture. The thickness of the steel at the point of injury in about four inche- 1 , and the crack, which is at present scarcely perceptible, is situated at some distance from the powder chamber, and is of small extent. It is believed that two' or three rounds have been fired since the injury happened, and that the gun is as fit for w..rk as ever-it was, the lining never being relied upon as contributing anything to the strength bt the barrel. The trial of the gun against the armor-plate at Shoebnryness will, therefore, probably take. place before it is re-tubed, as the delay of- that experiment would be inconvenient, seeing how much the construction of the guns depends upon the result; but it is understood that the few rounds remaining to test the ammunition will bs dispensed' with. The early removal of the gun from its present position facing the Maplia Sands may therefore be expected.