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"to come upon you; for then both the dryvine of the wether
and the thickinge of the ayre increaseth the marke, when
after the shower all thinges are contrarye, cleare and
caulme, and the marke for the most part new to begin
againe."
He likewise tells us of remarkable variations in the mark,
occasioned by shooting near the sea or any water: these I
have observed in rifle-shooting upon the brink of Ulswater,
and from hence we may conclude, that the certainty of the
two instruments was nearly equal. What a degree of exactness
this must have been the reader may judge, when I inform him,
that, with a rifle-gun, I myself could, almost to a
certainty hit a mark two inches in diameter at the distance
of 120 yards. I have likewise frequently observed, that in
shooting over damp and marshy ground, more gun-powder was
required to hit the mark than in shooting over dry ground.
The aberration of the ball towards the water I determined
thus: having regulated my gun, &c. so that I could hit a
mark upon dry level ground, of the magnitude, and at the
distance I mentioned before, I set up two targets very near
to Ulswater edge, and 120 yards distant from each other. I
then took my station at one of them, and firing at the
other, found the ball pretty exact as to elevation, but out
of the line of my aim near four inches: I then placed myself
at the target I had before shot at, and fired at the other,
and found the result precisely the same: these experiments I
repeated a great number of times, and found the same
variation, both in quantity and direction, viz. about four
inches, and always towards the water. Satisfied with the
accuracy of my observations, I mentioned them to several
philosophical gentlemen; some of whom honestly confessed
they knew nothing that could give a solution to this
paradoxical problem, and others again disbelieved the whole,
or at least pretended so to do. The reason seems to be
twofold; the air over the lake will always be cooler and
less rarified than that over the land; on this account, the
vapours raised from the banks of the lake will in their
ascent tend towards the water, and thus impell the shot in
that direction. Again, an account of the same rarefaction,
the line of sight, or (as gunner's call it)
Collimation, will not be a right line, but a curve
convex, towards the water: now the aim being (as is evident)
taken in a line, which is a targent (sic) to that curve,
must not strike the object, but another spot nearer to the
water than the object at which the gun is directed; we want
sufficient data to bring these quantities to
computation; otherwise the solution of them would be a very
useful and instructive problem, not only in gunnery, but in
every other science where the measuring of horizontal angles
is necessary.
From the above remarks, it should seem as if the bow might
almost cope with the rifle-gun, in accuracy of shot, and as
such I can almost give credit to the tales of our old
Archers. I am the more induced to this from the observation
of the great Dr Halley, who, in determining his problems of
gunnery, found a cross-bow to be more accurate than
any artillery he could prepare: now Ascham affirms the
cross-bow to be but a trifling engine, and we may thence (I
think) conclude that the bow was the surest instrument ever
devised. In point of utility in war, the musket must
undoubtedly claim precedence; the rifle though astonishingly
accurate, can hardly be discharged more than six times in an
hour, and the expence of arrows makes the bow a very costly
instrument; so that I think the art of war will, for some
centuries at least, continue upon the present plan; "there
is, however (as an elegant and learned author observes) a
pleasure in knowing what may be done, though it may
not always be the best for practice."
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