MECHANICS AND USEFUL ARTS. Ill 



isfactory. The 64-pouncler issued to Davenport has fired over 

 500 rounds; the gun is reported to be perfectly serviceable, and 

 no complaints have been made of any difficulty in working. The 

 Sheerness gun has fired 200 rounds, and the practice is reported 

 as exceedingly accurate. The report from Gibraltar speaks in 

 high terms of the accuracy of the 56-pounder issued to that sta- 

 tion. The gun lias fh-ed 400 rounds, and is perfectly serviceable. 

 The 56-pounder issued to Malta has fired 250 rounds. At Dover 

 a 64-pounder has fired over 180 rounds with remarkable accuracy. 

 The gun is spoken of as being, for handiness and fitness for rough 

 work and exposure, in every way equal to the old 32-pounder. 

 The 64-pounder on board the "Excellent" has fired over 180 

 rounds with great accuracy, the working of the gun-carriage, 

 etc., being in every way satisfactory. These reports are of much 

 interest, proving, as they do, that the converted 64-pounder guii 

 is fully equal to the more expensive wrought-iron gun of the 

 same calibre. — Median. Mag. 



PROOF OF GUNS. 



Mr. Whit worth says of the late trial of the 9-inch Frazer gun, 

 pronounced so wonderful by the British press, — namely, firing 19 

 tons of powder and 124^ tons of shot in 1,114 rounds, — that as 

 more than one-half the rounds fired were powder charges, only 

 one-half the most efi'ective charge, and the remainder with three- 

 quarters the charge, while all the shots fired were only two-thirds 

 the best weight for that size of bore, I contend that it was no 

 proper test of endurance, but sheer waste of ammunition. 



Mr. Whitworth thus describes his own mode of proof ; it con- 

 sists in preventing the shot from moving when the powder is ig- 

 nited, the gases generated by the explosion escaping only through 

 the touchhole. About one-sixth of the regular powder-charge fired 

 in this way gives the same strain to the gun as a full charge fired 

 in the ordinary manner. To prevent the movement of the shot, a 

 screw is cut on the periphery of the gun at the muzzle, and on it 

 is fitted a screwed cap having a solid end. The gun is loaded 

 with a caitrido:e of the ordinarv leniJ^th, but containins: one-sixth 

 of the regular charge, and supported by tin disks in the centre of 

 the bore ; a flat-fronted shot with tight wads to prevent any es- 

 cape of gas, and a round steel bar reaching from the shot to the 

 end of the bore, are then introduced, and^the cap with the solid 

 end screwed on. The gun is then ready for firing, after which 

 my measuring instrument is introduced into the bore, and any 

 enlargement to the ten-thousandth of an inch may be ascer- 

 tained. 



If there be no enlargement, the powder charges may be grad- 

 ually increased, imtil a slight enlargement has been produced. 

 The real strength of each gun is thus positively ascertained, and 

 this strength I would have stamped and recorded on each gun. 

 This would give confidence to the gunners, and would act as a 

 check on those enora^fcd in the manufacture. When the ultimate 



