PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 



427 



against the shot a longer than ordinary time, and the use of this device is 

 made practicable by the devices of compensation, and modes of attaining 

 great strength exhibited in the spherical guns hereinbefore described. 



F'ij 35 



' • K ^ W 



The figures represent a longitudinal. section of the gun, and a cross section 

 on line SS ; also, an end elevation, the right hand side being an elevation of 

 the rear end with a portion broken away, and the left hand side an elevation 

 of the front end. A is the inner lining of steel constructed in the form^ 

 represented, so that there is a chamber 31 larger than the main bore of the! 

 gun. This chamber ill is bored without difficulty, by means known to 

 workers in metal, and contains, in a form adapted to facilitate its rapid 

 ignition, a much larger quantity of powder than can be burned, with 

 advantage, behind a shot in guns of the ordinary construction. 5 is a 

 covering of bronze forced tightly upon the lining A. The inner surface of 

 B and the outer surface of A are tapered slightly; the rear end of ^ being 

 largest. This facilitates the production of a very tight fit of these parts, 

 but care must be taken that the thickest part of the steel lining A be not 

 too great. I prefer to make this thickness, if the gun be large, about three 



