[ 358 ] 



LVL Description of a Shell, exploding by Percussion when 



trod upon. By Lieut. -Col. Miller, F.R.S.* 

 'T'HIS is a very simple contrivance, and will easily be un- 

 -■" derstood from the figure. A spring is attached to the 

 upper part of the shell, which produces ignition by falling on 

 a copper cap ; and a support is placed under the spring, moving 

 on a hinge, with a handle attached to the support ; so that by 

 treading on the handle, the support is withdrawn, the spring 

 falls, and explosion follows. The sides of the shell must be 

 of equal thickness, for the better splintering; and as an oval 

 form will be the most convenient for fixing the spring. The 

 following construction is given : 



Length of shell 8 inches. 



Breadth of ditto 5*5 



Depth of ditto 5 



Length of chamber 6 



Width of ditto 3*5 



Height of ditto 3 



Length of spring 6 



Fall of ditto 1 



Length of handle from 10 to 30. 



Vertical section of shell when cocked, taken lengthwise. 





Shells of this description, it is conceived, might be made to 

 perform the duty of sentinels on many occasions, by giving 

 notice of the approach of an enemy, and presenting a con- 

 siderable obstacle to his advance by their explosion. They 

 might accordingly be used with advantage in the ditches of 



Communicated by the Author. 



fortresses, 



