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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."