104 ANNUAL OF SCIENTIFIC DISCOVERY. 



ENDURANCE OF HEAVY ORDXAXCE. 



A recent report by Gen. Gilmore, "On the Engineer and Military 

 Operations against the Defences of Charleston, in 1864," furnishes 

 some interesting information respecting the endurance of the heavy 

 rifled ordnance recently brought into use. According to this authority, 

 we have no guns of large caliber which will endure "with certainty 

 800, or even 500 rounds." The siege of Charleston was not aban- 

 doned until after 23 of the Parrott 100 and 200-pounders had burst. 

 The famous " Swamp Angel" battery, composed of one 8-inch rifle 

 gun, exploded at the 36th fire, blowing out the entire breech at 

 the rear of the vent, disheartening the men, and causing a suspen- 

 sion of the fire on the city. For purposes of offensive war, then, we 

 must have rifled ordnance of greater power and endurance than any 

 yet made ; and that nation which shall be the first to produce guns 

 " strong enough, " in the language of Gen. Gilmore, " to sustain the 

 repeated shock of at least 1.000 charges of powder, in as large quanti- 

 ties as can be burned with useful effect behind the projectile, and at 

 any required elevation," must have a decided advantage over all 

 others. 



"The average number of rounds," says Gen. Gilmore, " sustained 

 by Parrottfs 100 and 200-pounders, on Morris Island, excluding those 

 in which the bursting could be traced to the premature explosion or 

 breaking of a shell, was 310." The system of "reinforcing" or 

 " hooping" a gun with external hoops of steel or wrought iron, does 

 not always answer the purpose of adding strength to the gun. On 

 the contrary, it is often a source of weakness, " because in cast guns 

 (whether of iron, brass, or other metal,)" as Captain Blakely remarks, 

 "the outside helps but very little in restraining the explosive force of 

 the powder tending to burst the gun, the strain not being (always) 

 communicated to it by the intervening metal. The consequence is, 

 that,, in large guns, the inside is split, while the outside is scarcely 

 strained. This split rapidly increases, and the gun ultimately bursts." 



Gen. Gilmore says explicitly: "It is not to a want of strength 

 in the reinforce that the premature bursting of Parrott's guns is to 

 be attributed, for the reason that that is not where the guns generally 

 fail. The defect has been more prominently exhibited in the cast 

 iron." In other words, it is the hard, granulous metal itself which is 

 at fault, and not the workmanship, which is excellent, and the only 

 remedy for our failures is to be found in the adoption of other metals 

 and other processes of fabrication. 



In explanation of these failures, however, it is due to Mr. R. B. 

 Parrott, the inventor and manufacturer of the guns, to state that in a 

 letter in the Appendix, he urges that the explosions are not owing to 

 any defect in the material or style of the guns, but to inexperience in 

 the handling of them, and to causes of a peculiar and accidental 

 character. He avers that, taking the extensive and repeated tests to 

 which they have been exposed, they are an unquestionable success in 

 every way. 



Since the siege of Sebastopol the government of Great Britain has 

 expended over $12,000,000 in experiments witli wrought iron and 

 steel, at the Iloyal Arsenal at Woolwich, and Elswick ; and of o,000 



