APPENDIX. ‘201 
immediately join the harpoon, the danger of some part, 
particularly the ring breaking by the impetus of the dis- 
charge is always very great. Before I could succeed in my 
plan of gaining communication with vessels wrecked on a 
lee shore by a shot with a line attached to it, I failed in 
every instance, until I had discovered some material to 
connect the rope to the ball, that would withstand the 
shock of the discharge. I therefore speak on this point 
with the certainty of experience. 
The following representation gives the gun, loaded with 
the harpoon, as on the point of being discharged. 
It is evident, that so much of an instrument like the har- 
poon of considerable weight^, left protruding from the 
muzzle of the gun, must confine the point blank range to 
a very few yards indeed : the parabola, or curve, must 
take place almost at the very moment of discharge. To 
counteract this, the gun must, like a mortar, be fired at a 
great elevation : but the requisite geometrical means of 
ascertaining the due elevation cannot here be practised ; 
and the aim must, consequently, always be uncertain. I 
have already noticed the very tardy flight of a body thus 
discharged, with a force inadequate to its weight ; and, 
when to this want of velocity is added a circuitous direc- 
tion, the fish may have dived from terror at the flash or re- 
* Those which were sent me from Hull, and procured for the 
purpose of making experiments, exceeded seven pounds in weight, 
and were two feet and a half in length. 
