upon Gun-powder^ &c. 301 
The bullets (hould be made to fit the bore with very little 
windage ; and it would be better if they were all caft in the 
lame mould, and of the fame parcel of lead, as in that cafe 
their weights and dimenfions would be more accurately the 
fame, and the experiments would of courfe be more conclu five. 
The ftated charge of powder may be half an ounce, and it 
fliould always be put up in a cartridge of very fine paper ; and 
after the piece is loaded it fhould be primed with other powder, 
firil taking care to prick the cartridge by thrufting a priming 
wire down the vent. 
As it appears, from feyeral experiments made on purpofe to 
afcertain the faft, that ramming the powder more or lefs has a 
very fenfible effecl to increafe or diminilh the force of the 
charge ; to prevent any inaccuracies that might arife from that 
caufe, a ram-rod, fuch as is reprefented fig. 15. may be made 
ufe of. It is to be made of a cylindric piece of wood in the 
fame manner as ram- rods in general are made, but with the 
addition of a ring C, about one inch and a half, or two inches 
in diameter, which, being placed at a proper diftance from the 
end [a) of the ram-rod that goes up into the bore, will prevent 
its being thruft up too far. This ring may be made of wood, 
or of any kind of metal as Hull be found moft convenient. 
The other end of the ram-rod (£) may be 31 or 32 inches in 
length from the ring, and the extremity of it being covered 
with a proper fubftance, it may be made ufe of for wiping out 
the barrel after each experiment. 
The machine ( f) for the tape to Hide through may be the 
fame as is defcribed by Dr. hutton in his account of his expe- 
riments on the initial velocities of cannon balls ; as his me- 
thod is much better calculated to anfwer the purpofe than that 
propofed and made ufe of by Mr. robins. It will alfo be 
Vol. LXXL S f better 
