Mathematicall recreations. Or a collection of sundrie problemes, extracted out of the ancient and moderne philosophers, as secrets in nature, and experiments in arithmeticke, geometrie, cosmographie, horolographie, astronomie, navigation, musicke, opticks, architecture, staticke, machanicks, chimestrie, waterworkes, fireworks, &c. ... Most of which were written first in Greeke and Latine, lately compiled in French, by Henry Van Etten Gent. And now delivered in the English tongue, with the examinations, corrections, and augmentations.

PROBLEM. LXXXIII. Of Cannons or great Artillery. Souldiers, and others would willingly see this Probleme, which containes three or foure sub∣tile questions: The first is how to charge a Cannon without Powder.

THis may be done with aire and water only, having throwne cold water into the Can∣non, which might be squirted forceably in by the closure of the mouth of the Peece, that so by this pressure the aire might more condence; then having a round peeee of wood very just, and oyled well for the better to slide, and thrust the Bullet when it shall be time: This peece of wood may bee held fast with some Pole, for feare it be not thrust out before his time: then let fire bee made about the Trunion or hinder part of the Peece to heate the aire and water, and then when one would shoote it, let the pole be quickly loosened: for then the aire search∣ing a greater place, and having way now offe∣red, will thrust out the wood and the bullet very quicke: the experimence which wee have in long trunkes shooting out pellats with aire on∣ly, sheweth the verity of this Probleme.

2. In the second question it may be demanded, how much time doth the Bullet of Can∣non spend in the aire before it falls to the ground.

THe resolution of this Question depends up∣on the goodnesse of the Peece and charge thereof, seeing in each there is great difference. It is reported that Ticho Brahe, and the Lands∣grave did make an ex∣periment

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upon a Can∣non in Germany, which being charged and shot off; the Bullet spent two minutes of time in the aire before it fell: and the distance was a German mile, which distance pro∣portionated to an houres time, makes 120. Italian miles.

3. In the third question it may be asked, how it comes to passe, that a Cannon shooting up∣wards, the Bullet flies with more violence than being shot point-blanke, or shoo∣ting downeward.

IF we regard the effect of a Cannon when it is to batter a wall, the Question is false, seeing it is most evident that the blowes which fall

perpendicular upon a wall, are more violent than these which strikes byas-wise or glaun∣singly.

But considering the strength of the blow on∣ly, the Question is most true, and often experi∣mented to be found true: a Peece mounted at the best of the Randon, which is neare halfe of the right, conveyes her Bullet with a farre greater violence than that which is shot at, Point blanke or mounted paralell to the Hori∣zon.

The cōmon reason is, that shooting high, the fire carries the bowle a longer time in the aire, and the aire moves more facill upwards, than downewards, because that the ayrie circles that the motion of the bullet makes are soonest bro∣ken. Howsoever this be the generall tenet, it is curious to find out the inequallity of moving of the aire; whether the Bullet fly upward, downeward, or right forward, to produce a sencible difference of motion: and some thinke that the Cannon being mounted, the Bullet pres∣sing the Powder maketh a greatar resistance, and so causeth all the Powder to be inflamed before the Bullet is throwne out, which makes it to be more violent than otherwise it would be. When the Cannon is otherwise disposed, the contrary arives, the fire leaves the Bullet, and and the Bullet rouling from the Powder resists lesse: and it is usually seene, that shooting out of a Musket charged onely with Powder; to shoote to a marke of Paper placed Point blanke, that there are seene many small holes in the

paper, which cannot be other than the graines of Powder which did not take fire: but this latter accident may happen from the overchar∣ging of the Peece, or the length of it, or windy, or dampenesse of the Powder.

From which some may thinke, that a Cannon pointed right to the Zenith, should shoote with greater violence, than in any other mount or forme whatsoever: and by some it hath beene imagined, that a Bullet shot in this fashion hath beene consumed, melt, and lost in the aire, by reason of the violence of the blow, and the acti∣vitie of the fire; and that sundry experiments hath beene made in this nature, and the Bullet never found. But it is hard to beleeve this as∣sertion: it may rather be supposed that the Bul∣let falling farre from the Peece cannot be discer∣ned where it falls: and so comes to be lost.

4. In the fourth place it may be asked, whether the discharge of a Cannon be so much the greater, by how much it is longer.

IT seemeth at the first to bee most true, that the longer the Peece is, the more violent it shootes: and to speake generally, that which is direction by a Trunke, Pipe, or other concavi∣tie, is conveyed so much the more violent, or better, by how much it is longer; either in re∣spect of the sight, hearing, water, fire, &c. and the reason seemes to hold in Cannons, because in these that are long, the fire is retained a lon∣ger time in the concavitie of the Peece, and so

throwes out the Bullet with more violence; and experience lets us see that taking Cannons of the same boare, but of diversitie of length from 8 foote to 12; that the Cannon of 9 foote long hath more force than that of 8 foot long, and 10 more than that of 9, and so unto 12 foote of length. Now the usuall Cannon carries 600 Paces, some more, some lesse; yea, some but 200 Paces from the Peece, and may shoote into soft earth 15 or 17 foote, into sand or earth which is loose, 22 or 24 foote; and in firme ground, about 10 or 12 foot, &c.

It hath beene seene lately in Germany, where there was made Peeces from 8 foote long to 17 foote of like boare, that shooting out of any Peece which was longer than 12 foote; the force was diminished, and the more in length the Peece increaseth, the lesse his force was; therefore the length ought to bee in a meane measure; and it is often seene, the greater the Cannon is, by so much the service is greater: but to have it too long or too short, is not con∣venient, but a meane proportion of length to bee taken; otherwise the flame of the fire will bee overpressed with aire: which hinders the motion in respect of substance, and distance of getting out,

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