1879.] on the ' Thunderer ' Gun Exjjlosion. 245 



would send it, and thus, unless the gun is being watched during these 

 4 to 6 seconds, no one can tell how the gun got to the spot where tho 

 recoil, if there had been one, would have jjut it, whctlicr by tho recoil 

 or by the hydraulic. Thus all three grounds for the " impossible " 

 fail. Simultaneous electric firing makes an end of the information to 

 be given by the noise of the explosion ; telescopic rammers, of the in- 

 formation to bo aflbrded by the length of rammer left protruding from 

 the gun ; and hydraulic runuing-in masks the recoil and renders that 

 source of information nugatory. 



Just a few words about other suggested causes. 



First, and most important, that the gun was inherently too weak. 

 I will not trouble you with the calculation which proves that it is 

 abundantly strong, not only to bear a charge of 85 lbs. of j^ebble 

 powder, but to bear far greater charges, but I will ask you to consider 

 facts. The fellow gun has fired precisely the same number of rounds, 

 and is unstrained. The two 35-ton guns, which I have told you are 

 the same as the 38 only shorter, have also fired the same number of 

 rounds, and with the same result. At the time of the explosion there 

 were many guns identical with the exploded gun, with the important 

 exception that they were bored to 12 J inches instead of to 12 inches, and 

 that therefore they were subjected to greater total pressure, and that 

 they had less metal to resist it. These guns had each been proved with 

 at least two rounds of 150 lbs. of P^ powder, and at least 130 lbs. of 

 similar powder, the projectile used weighing over 800 lbs. One gun, 

 No. 1, had fired 271 rounds varying from 130 lbs. to 170 lbs. of powder, 

 with an 800-lb. projectile; another gun, 217 rounds of the same 

 character as those last mentioned ; and another gun, an experimental 

 one, 503 rounds, some of them containing as much as 200 lbs. of 

 powder. Since the explosion, the ' Dreadnought's ' four 38-ton guns 

 have been tried. This was done on the 29th and 30th of April, when 

 70 rounds were fired from them. These guns are hydi-aulically worked 

 and loaded like those of the ' Thunderer.' Full charges and batter- 

 ing charges were used, and projectiles of as much as 800 lbs;* 

 the ' Dreadnought's ' guns being of 12^ inches bore in lieu of 

 the ' Thunderer's ' 12 inch, and being thereby weaker than the 

 ' Thunderer's ' guns ; and these trials have been attended with 

 the most favourable results. 



The next suggested cause is that the gun had been injured by 

 previous service. It is sufficient to say that the other guns in the 

 ship had had an exactly similar service and are uninjured, and that 

 there is not an appearance of the commencement of a crack in that 

 part of the exploded gun where cracks do commence when a gun is 

 beginning to fail. 



* In the case of these 12^-iuch guns the full charge is as much as 100 lbs. 

 while the battering charge is 130. On more than one occasion charges of 160 lbs! 

 were used, and at the close of the Wednesday's proceedings an electric broad- 

 side was given with all four guns thus loaded. 



