But the immediate cause of the Report is the vehement commotion of the air upon the sudden and violent eruption of the Powder; for that being suddenly fired, and almost altogether, upon this high rarefaction, requireth by many degrees a greater space then before its body occupied; but finding resistance, it actively forceth his way, and by concusion of the air occasioneth the Report. Now with what violence it forceth upon the air, may easily be conceived, if we admit what Cardan affirmeth, that the Powder fired doth occupy an hundred times a greater space then its own bulk; or rather what Snellius more exactly accounteth; that it exceedeth its former space no less then 12000 and 500 times. The cause of Thunder. And this is the reason not only of this fulminating report of Guns, but may resolve the cause of those terrible cracks, and affrighting noises of Heaven; that is, the nitrous and sulphureous exhalations, set on fire in the Clouds; whereupon requiring a larger place, they force out their way, not only with the breaking of the cloud, but the laceration of the air about it. The greatest distance of the Clouds. When if the matter be spirituous, and the cloud compact, the noise is great and terrible: If the cloud be thin, and the Materials weak, the eruption is languid, ending in coruscations and flashes without noise, although but at the distance of two miles; which is esteemed the remotest distance of clouds. And therefore such lightnings do seldom any harm. And therefore also it is prodigious to have thunder in a clear sky, as is observably recorded in some Histories.
The cause of Earthquakes.
From the like cause may also proceed subterraneous Thunders and Earthquakes, when sulphureous and nitreous veins being fired, upon rarefaction do force their way through bodies that resist them. Where if the kindled matter be plentiful, and the Mine close and firm about it, subversion of Hills and Towns doth sometimes follow: If scanty, weak, and the Earth hollow or porous, there only ensueth some faint concussion or tremulous and quaking Motion. Surely, a main reason why the Ancients were so imperfect in the doctrine of Meteors, was their ignorance of Gunpowder and Fire-works, which best discover the causes of many thereof.
Now therefore he that would destroy the report of Powder, must work upon the Petre; he that would exchange the colour, must think how to alter the Small-coal. For the one, that is, to make white Powder, it is surely many ways feasible: The best I know is by the powder of rotten Willows, Spunk, or Touch-wood prepared, might perhaps make it Russet: and some, as Beringuccio In his Pyrotechnia. affirmeth, have promised to make it Red. All which notwithstanding doth little concern the Report, for that, as we have shewed, depends on another Ingredient. And therefore also under the colour of black, this principle is very variable; for it is made not onely by Willow, Alder, Hazel, etc. But some above all commend the coals of Flax and Rushes, and some also contend the same may be effected with Tinder.
As for the other, that is, to destroy the Report, it is reasonably attempted but two ways; either by quite leaving out, or else by silencing the Salt-petre. How to abate the vigour thereof, or silence its bombulation, a way is promised by Porta, not only in general terms by some fat bodies, but in particular by Borax and butter mixed in a due proportion; which saith he, will so go off as scarce to be heard by the discharger; and indeed plentifully mixed, it will almost take off the Report, and also the force of the charge. That it may be thus made without Salt-petre, I have met with but one example, that is, of Alphonsus Duke of Ferrara De examine Salium., who in the relation of Brassavolus and Cardan, invented such a Powder as would discharge a bullet without Report.
That therefore white Powder there may be, there is no absurdity; that also such a one as may give no report, we will not deny a possibility. But this however, contrived either with or without Salt-petre, will surely be of little force, and the effects thereof no way to be feared: For as it omits of Report so will it of effectual exclusion, and so the charge be of little force which is excluded. For thus much is reported of that famous Powder of Alphonsus, which was not of force enough to kill a Chicken, according to the delivery of Brassavolus. Jamque pulvis inventus est qui glandem sine bombo projicit, nec tamen vehementer ut vel pullum interficere possit.
It is not to be denied, there are ways to discharge a bullet, not only with Powder that makes no noise, but without any Powder at all; as is done by Water and Wind-guns, but these afford no fulminating Report, and depend on single principles. And even in ordinary Powder there are pretended other ways to alter the noise and strength of the discharge; and the best, if not only way, consists in the quality of the Nitre: for as for other ways which make either additions or alterations in the Powder, or charge, I find therein no effect: That unto every pound of Sulphur, an adjection of one ounce of Quick-silver, or unto every pound of Petre, one ounce of Sal Armoniac will much intend the force, and consequently the Report, as Beringuccio hath delivered, I find no success therein. That a piece of Opium will dead the force and blow, as some have promised, I find herein no such peculiarity, no more then in any Gum or viscose body: and as much effect there is to be found from Scammony. That a bullet dipped in oyl by preventing the transpiration of air, will carry farther, and pierce deeper, as Porta affirmeth, my experience cannot discern. That Quick-silver is more destructive then shot, is surely not to be made out; for it will scarce make any penetration, and discharged from a Pistol, will hardly pierce through a Parchment. That Vinegar, spirits of Wine, or the distilled water of Orange-pills, wherewith the Powder is tempered, are more effectual unto the Report than common Water, as some do promise, I shall not affirm; but may assuredly more conduce unto the preservation and durance of the Powder, as Cataneo hath well observed. Cat. avertimenti intorne a un Bombardiero.
That the heads of arrows and bullets have been discharged with that force, as to melt or grow red hot in their flight, though commonly received, and taken up by Aristotle in his Meteors, is not so easily allowable by any, who shall consider, that a Bullet of Wax will mischief without melting; that an Arrow or Bullet discharged against Linen or Paper do not set them on fire; and hardly apprehend how an Iron should grow red hot, since the swiftest motion at hand will not keep one red that hath been made red by fire; as may be observed in swinging a red hot Iron about, or fastning it into a Wheel; which under that motion will sooner grow cold then without it. That a Bullet also mounts upward upon the horizontall or point-blank discharge, many Artists do not allow: who contend that it describeth a parabolical and bowing line, by reason of its natural gravity inclining it always downward.
But, Beside the prevalence from Salt-petre, as Master-ingredient in the mixture; Sulphur may hold a greater use in the composition and further activity in the exclusion, then is by most conceived. For Sulphur vive makes better Powder then common Sulphur, which nevertheless is of a quick accension. For Small-coal, Salt-petre, and Camphire made into Powder will be of little force, wherein notwithstanding there wants not the accending ingredient. And Camphire though it flame well, yet will not flush so lively, or defecate Salt-petre, if you inject it thereon, like Sulphur; as in the preparation of Sal prunellæ. And lastly, though many ways may be found to light this Powder, yet is there none I know to make a strong and vigorous Powder of Salt-petre, without the admixtion of Sulphur. Arsenic red and yellow, that is Orpement and Sandarach may perhaps do something, as being inflamable and containing Sulphur in them; but containing also a salt, and mercurial mixtion, they will be of little effect; and white or crystalline Arsenic of less, for that being artificial, and sublimed with salt, will not endure flammation.