256 REPORT — 1861. 



that any smootli-bored gun abore the 68-pouiider, and any rifled gun of even half 

 that size must burst after very few rounds with full charge of powder. Now, Cap- 

 tain Blakely maintained, there was no difficulty in making guns ten times more 

 powerful. He believed that not onlj^ a 600-poimder, but even a 6000-poxmder 

 could be constructed, if great care were taken in selecting the best materials, and 

 in putting on the outer layers with the exact degi-ee of tension required to enable 

 them to exert their strength. If the outer layers (he used them generally in the 

 form of lings) were too tight, they burst before tlie central part ; and if they were 

 too loose, the central parts burst iirst, and perhaps left the rings whole. Exten- 

 sive experiments had been made to determine the proper degree of tension for these 

 rings, because on that point depended the efficiency of the gun. Not only had he 

 (CaptainBlakely) made such experiments, but also the Spanish andEnglish Govern- 

 ments, — the latter having made several hundred fall-sized cannon, some of which 

 were built up entirely of iron, the tension of the outer portion being varied — some 

 being constructed partly of iron, partly of brass. It was well worth the trouble of 

 any person desirous of studying the question to \-isit "Woolwich Arsenal and see 

 the broken fragments of these cannon. Captain Blakely believed the truth might 

 have been arrived at with less expense ; however, the result was the acknowledg- 

 ment by the Select Ordnance Committee of the exactness of Captain Blakeh^'s 

 views in reference to cannon, viz. that all large guns must be built up, that the 

 outer parts must be in a state of initial tension, and that so definite, that the 

 .slightest excess or deficiency of tension detracts from the strength of the gun. 

 All guns now made in the English Arsenals are constructed on those principles — 

 though afterwards spoilt, in his opinion, by the weakening of the breech for the 

 pm-pose of loading by that end. Spanish guns also are now built up. Captain 

 Blakely exhibited the drawing of the new Spanish naval gun, and explained its 

 construction. The diameter of the bore was between six and seven inches ; more 

 than half of the gun, he said, was of cast iron, the upper portion of the breech only 

 being formed of rings of steel. 



Captain Blakely regi'etted that the English Government did not obtain all the 

 advantages fi'om the system which he thought it capable of aflbrding. They re- 

 fused to make any cannon larger than 120-pounders — perhaps because Sir William 

 Amistrong's breech-loading apparatus was not adapted for large guns ; and they also 

 refused his (Captain Blakely's) ofler to make at his own expense a 600-pounder, 

 and lend it to them for experiment against their model t.argets. He would not say 

 anything of the policy of this conduct, but he believed he was in order in saying 

 that it was not "philosophical" to refuse to try a larger gim, and at the same time 

 to proclaim that the plates, constmcted to resist little lOO-pound pop-guns, were 

 "impeneti-able."' Eor his part he firmly believed that he could make cannon either 

 to punch holes through not only 4:-inch but 8-inch plates, or, what was better 

 still, to crush them completely. 



On Recent Improvements in Cotton-Gins. 

 By Dattd Chadwick, F.S.S., of the Manchester Committee. 

 A description was given of the old Indian chm-ka, one of which was exhibited 

 to the Meeting ; and the invention of the American saw gin, by Eli AVhitney, was 

 also noticed and described. On the recent visit to England of Dr. Forbes, the 

 superintendent of the cotton-gin factory of the late East India Company, to Darwhar, 

 he introduced an improved cotton-gin, based upon the principle of the Indian churka. 

 This chm-ka gin had subsequently been improved by ^Ir. John Dunlop, of Man- 

 chester, and Messrs. Piatt Brothers, of Oldham ; and the improved machines were 

 exhibited to the Meeting. The improvements in Messrs. Piatt's machines con- 

 sisted in the application of spike rollers revolving at different speeds in connexion 

 with vibrating machinery, which ti'ansmits the cotton to the ordinary churka rol- 

 lers. The effect of this "is to enable the machine to be supplied with cotton con- 

 tinuously instead of at intenals with the fingers. The machine is intended to be 

 worked by power, and requires the attendance only of a child thirteen years of age. 

 Mr. Dunlop's machine was less expensive, but more compact, and bearing a closer 

 resemblance to the original chm-ka, and was intended to be worked by hand. 



