464 
[Extract from.\ the Miscellaneous Works of Mr . John Greaves (Savillian), 
Professor of Astronomy in the University of Oxfordi] 
AN ACCOUNT BY MR. J, GREAYES OF SOME EXPERIMENTS 
FOR TRYING THE FORCE OF GREAT GUNS. 
COMMUNICATED BY 
MAJOR TRACEY, R.A. 
1651, Maeoh 18, 
WooiiWicE:, 
At 200 yds, distance from tlie platform for great ordnance there 
were raised 3 butts, one behind another. The space between the 1st 
and 2nd butt was 14 yds., between the 2nd and 3rd 8. 
The thickness of each butt was 19 ins. j whereof 13 was of beams of 
massy oak fastened into the ground, and set so close that they touched 
each other. 
On each side were planks of oak, 3 ins. a piece in thickness ; and 
these were joined close, and fastened on both sides with iron bolts and 
strong pins of wood j and on the back, at the ends, and on the middle 
there were three braces of elm, a foot in breadth, and five inches in 
thickness. 
The 1st experiment was with an iron demi-cannon of 3500 lbs, 
weight, the bullet 32 lbs. of iron, the powder 10 lbs., which pierced 
thro J the two first butts, and struck in the third, so as the ball was 
almost quite within, but the timber not shivered small, nor scarce 
split. The butts, being touched by me, felt quite warm. 
The like execution was done when it was charged with 9 lbs., as 
also when with 8 lbs. of powder. This demi-cannon was with a 
cylinder bore. 
The 2nd experiment was with a demi-cannon having a taper bore, 
and being 3600 lbs. in weight, and 4 ins. longer than the former, the 
iron bullet 32 lbs., and the powder 7 lbs., which in three trials seemed 
to have the same force with the first. One of the shots, piercing 
through the 2nd butt and lighting near the edge of the middle butt of 
elm, tore it; but by the yielding of it, the bullet glanced aside off the 
3rd butt, and entered into the earth. 
