342 
Lead . 
on the end surface, to cause the blast of the powder and 
the resistance of the air to concur in producing the same 
rotation. 
For this purpose I took a wooden pattern, and cut the 
spherical surface into twelve spiral planes, by dividing 
the equator into the like number of equal parts, and draw- 
ing spirals from the points of division obliquely towards 
the poles. The wood between every pair of contiguous 
spirals was then taken away, by cutting from the one line 
parallel to the axis, and from the other perpendicular to a 
plane passing through it. By this process, when the axis 
was set upright, there appeared, as it were, twelve roads 
sloping upwards from the equator towards the pole, 
bounded on the side next the wood by upright walls ; and 
the shot, when suspended on an axis or centre point, 
could be blown round very swiftly by the breath direct- 
ed towards the pole. 
Shot of this kind were made and tried at a foundery in 
North Wales. By an experiment with a brass gun new- 
ly bored, it was ascertained that the shot did really revolve 
in its course along the bore ; but the trials with shot of 
different weight and dimensions did not promise more ac- 
curacy of effect than was obtained by common spherical 
shot used at the same time. Particular notice was taken 
of the manner in which the shot struck the butt : the 
greatest number of times, it struck with the anterior end ; 
sometimes the stroke was made with the broad side, and, 
in a few instances, the end which came last out of the gun 
Arrived first at the mark. Hence it appears, that the very 
slight angular deviation at the mouth of the piece is more 
than sufficient to counteract any effect which might else 
have been derived from the subsequent action of the air 
upon a" projectile d figured. 
It seems, nevertheless, that this principle might be ap- 
plied to advantage in bar shot. If the ends of this pro- 
