G U 
powder, the longer piece will, ftri£lly fpeaking, com¬ 
municate the greater velocity and force to its ball, or 
ffiot. But, as the inflammation of the powder has been 
fhewn to be nearly inftantaneous, apid as the incrcaff of 
acceleration, which the ball or fhot receives after the 
firft impulfe of the powder upon it, is not very confi- 
derable ; it follows that the force with which two bar¬ 
rels of the fame bore, and with the fame charge, throw 
their ball or fhot, will be nearly the fame, unlefs their 
lengths be extremely difproportionate. 
To prove this, we fhall quote what is faid by that 
able mathematician and engineer Mr. Benjamin Robins. 
“ If a mufquet-barrel, of the common length and bore, 
be fired with a leaden bullet and half its weight of 
powder, and if the fame barrel be afterwards fhortened 
one-half, and fired with the fame charge, the velocity 
of the bullet hi this fhortened barrel will be about one- 
lixth Iefs than what it was when the barrel was entire j 
and if, inftead of fhortening the barrel, it be increafed 
to twice its tifual length, (when it will be near eight 
feet long,) the velocity of the bullet will not hereby 
be augmented more than one-eighth part. And the 
greater the length of the barrel is in proportion to the 
diameter of the bullet, and the fmaller the quantity of 
powder, the more inconfiderable will thefe alterations 
of velocity be.” 
When the allowances which Mr. Robins here takes 
notice of are made, in the proportion required for fowl¬ 
ing-pieces, the refult will be found to correfpond ex- 
aftly with the experiments which we have repeatedly 
made, with every poflible attention to accuracy. We 
have, at different times, compared barrels of all the in¬ 
termediate lengths between twenty-eight and forty 
inches, and of nearly the fame caliber ; and thefe trials 
were made both by firing-tire pieces from the fhoulder, 
and from a firm block, at an equal diftance, and with 
equal, weights of the fame powder and of the fame ffiot. 
To avoid every podibility of error, the quires of paper 
at which we fired were fixed againft planks, inftead of 
being placed againft a wall. From thefe trials, fre¬ 
quently repeated, we found that the fhot pierced an 
equal number of ftieets, whether it was fired from a 
barrel of 28, 30, 32, 34, 36, 38, or 40, inches in length. 
Nay more, we have compared two barrels of the fame 
caliber, but one of them thirty-three and the other 
fix.ty-fix inches long,, by repeatedly firing them, in the 
fame manner as the others, at different diftances, from 
forty-five to one hundred paces, and the refults have 
always been the fame; that is to fay, the barrel of 
thirty-three inches drove its ffiot through as many 
flieets of paper as that of fixty-fix did,, at the fame dif- 
tances. The conclufi.on from.all this is, that the dif¬ 
ference of ten inches in. the length of the barrel, which 
Rems to be more than is ever infilled qpon among 
fportfmen, produces no fenfible difference in the range 
of the piece ; and therefore, that every one may pleafe 
himfelf in the length of his barrel, without either de¬ 
triment or advantage ta the range. 
The circumftance of a duck-gun killing at a greater 
diftance than a fowling-piece, is not owing to its length, 
but to its greater weight and thicknefs, allowing the 
charge of powder to be doubled,, trebled, or even qua¬ 
drupled ; which, cannot be done in a fpwling T piece,. 
though ftrongly reinforced. For a barrel of five or fix 
feet,, fuck as that of a common duck-gun, weighing- 
five or fix pounds, and the whole piece twelve or thir¬ 
teen pounds, may be fired with a very large charge, 
without recoiling fo much as to hurt the (hooter, its 
weight being fufticient to refill the violent impulfe oc- 
Ci.fioned by the increafe of the powder. But in a fowl- 
irg-piece of three-feet barrel, fuffkiently ftrong to witli- 
liand Inch a charge, and whole weight all together does 
not exceed five or fix pounds, the recoil would be in- 
lupportable. Befides, they not only double or treble 
the powder in a duck-gun, but they put in a much 
N. 103 
greater quantity of fhot than is ever employed in a 
fowling-piece. Duck-guns are generally bent a little 
upwards n,ear the muzzle, which, the gunfmiths fay, 
makes them throw their fhot farther than if they were, 
perfedtly ftraight. To obtain, therefore, from a piece 
of the ordinary length, the fame effects as from a duck- 
gun, nothing more, perhaps, is neceffary, than to have 
the barrel fuffkiently ftrong to admit of the charge 
being doubled or trebled as required, and. the whole 
piece heavy enough to render the recoil fupportable. 
We may here obferve, however, that an increafe of the 
powder above the charge generally ufed, does not 
produce a proportional increafe of range in the ball or 
ffiot: thus a double charge of powder will not throw 
the ball or ffiot twice the diftance, nor a treble charge 
to three times the diftance, the dingle charge does. 
This arifes from the great reffftance given by the air to 
the motion of the ball or ffiot, and which is proved to 
be fourfold if the velocity be doubled, and ninefold 
when it is trebled, by an increafe of powder ; for the 
reffftance of the air is not proportional to the velocity 
itfelf, but only to the fquare of the velocity*. Thus 
Bernouilli, mathematical profeffor in Bafil, difcovered 
from experiment that a ball which,.being fired, afcended 
only (even thoufand eight hundred and nineteen feet in 
the air, would afcend fifty-eight thoufand feven hun¬ 
dred and fifty feet in vacuo. Still we may fafely infer, , 
that, if the adlion of the powder be not diminiflied by 
circumftances of defeat in the formation of the barrel, . 
the greater the force of the powder, the greater muft 
be the velocity of the ball. So great is the change in 
opinion of late, with regard to the proper length for 
gun-barrels, that many gunfmiths will now tell us, that 
fhort barrels carry farther than long Ones ; and the rea- 
fon they give for this, is, the greater friction- of the 
ball or (hot in palling through a long barrel, by which . 
their velocity is retarded and their force diminiflied. 
If the barrel be fo long that the additional impulfe 
which the ball or flybt is continually receiving in its, 
padage becomes lefs than the frktion between them' and 
the lides of the caliber, then, indeed, the barrel by 
being fhortened will flioot with more force : but, as 
the length of barrel required to produce this effect is 
vaftly greater than can ever be employed for any pur- 
pofe, the objection does not hold. And it feems clear, , 
that a piece may be made fo long, that it will not throw 
a ball with fo great a velocity as one that is conlide- 
rably fhorter; and the reafon of this decreafe of velo¬ 
city may. be, that in very long pieces the increafe of 
the'counterpreflure of the external air in the cylinder- - 
may greatly exceed the force of the powder, and that 
the elaftic fluid generated by the explofion of the pow¬ 
der is cotiftantly efcaping. whilft the ball pades along 
the cylinder, which it not only does at the touch-hole, 
but alfo between the ball and the ddes of the' barrel ; 
and hence may be inferred the neeedity of touch-holes 
which do not prime of thejnfelves, and of wadding 
that flops the barrel hermetically. 
Having thrown every light upon this queftion that is 
necedary to.determine 11s in our choice of the length, 
it will, perhaps, be expedled that we give our opinion, 
what length of barrel is bed:.calculated for general life. 
'I he barrels which are found to anfwer bell for every 
purpofe, are from thirty-two to thirty-eight inches; 
and whether we confult the appearance of the piece, 
its lightnefs, or the eafe.wi.th which it is managed, we 
believe that a barrel not exceeding the one, or below 
the other, of thefe numbers, is the moft eligible. We 
know that many of the fafhionable gunfmiths pique 
themfelves on the proportion they give to the different 
parts of their fowling-pieces, .and tnence ded.uce a fu- 
periority over their cotempnrai ies in favour, of their 
own : to us it appears that the beauty of thofe propor- . 
tions is more attended to, than any good read?n why 
they are made do rather than otherwile. 
CAUSES 
