On the Earliest Fireworks containing Nitre, As we can add nothing to this subject from oriental history or tradition, beyond the testimonies which we have already quoted, we shall here take up the first positive evidence that we can find respecting the know ledge of explosive fireworks, in or near to Europe. In these nitre is an indispensable ingredient, whatever may be deemed respecting some of the varieties, at least of the Greek fire ; and they may be considered as belonging to the family of gunpowder. The first po sitive authority that we can find on this subject is the Arabic author already mentioned in 1249, who is trans lated by Casiri in his Ribliotheca Arabo-Hispanica The passage is as follows : " Serpunt susurrantquc scorpiones circumligati ac pulvere nitrato incensi ; uncle exp!osi fulgurant atque susurrant. Jam videre erat manganum excussum veluti nubem per aera extendi, ac tonitrus instar horrendum edere fragorem, ignemque undequa que vomens omnia dirumpere, incendere, in cineres redigere." Here again we are somewhat puzzled to choose between rockets and shells or carcasses. The " serpunt," the " susurrant," and the " circu rnligati ," apply but to the description of the former. But the use of the " manganum," from whence our early engine, the mangonel, derived its name, bespeaks a mechanical force which could not have been required for a rocket, and is moreover not very easy of application. We might almost conclude the same from the effects ; " omnia dirumpere, incendere, in cineres redigere," applies rather to a shell than a rocket ; unless indeed these were contrived like the Congreve rockets, so as to carry a shell with them. At any rate, the use of nitre, and the true nature of the composition, as far as that goes, is unquestionable.
The next authority is decisive respecting the rocket, and it is found in a manuscript quoted by Dutens, from which Roger Bacon is supposed to have derived his knowledge of fireworks. The author's name is Marcus Gr2ecus, and by the title it appears to be a general es say on military pyrotechny. " Incipit Tiber ignium a Marco Graco perscriptus, cujus virtus et effieacia est ad comburendum hostes, tam in marl quam in terra." The directions for making a rocket are as follow: Secundus modus, ignis volatilis hoc modo conficitur; R. Libras duas sulphuris vivi, libras duas carhonis salicis, salis petrosi libras sex ; gum tria subtilissime tereantur in lapidc marmorea; postea pulvis ad libitum in tunica reponatur volatili vel tonitrum facientia. Nota, quad tunica ad volandum debet esse gracilis et longa, et prxdicto pulvere optime calcato repleta ; tunica vel tonitrum faciens debet esse brevis, grossa, et pr2edicto pulvere semiplena, et ab utraque parte filo fortissimo bene ligata. Nota, quod in qualibet tunica primum foramen faciendum est, ut tanta imposita accendatur ; (lux tenta in extremitatibus fit gracilis, in media vero lata, et prxdicto pulvere repleta. Nota, gum ad volandum tunica plicaturas ad libitum habere potest, tonitrum vero faciens quam plurimas plicaturas. Nota, quod duplex poteris facere tonitrum, ac duplex volatile instrumentum, vel tunicam subtiliter in tunica includendo." There is here no direction, it is true, for boring a rocket, without which it cannot fly by its own recoil, so that it is possible this firework was a kind of squib, intended to be rendered " volatile" by mechanical means, and not by its own unassisted en ergy. We think it not unlikely that this is the very
fire of Joinville ; and the distinction into two the " tunica volatilis," and the " tonitrum faciens," confirms our notion that these ancient projectiles com bined the nature of a shell and a rocket together.
The claims of Roger Bacon to the invention of gun powder, or of any nitrous explosive compounds, how ever often repeated, arc nothing, as may indeed be proved from his own narration ; and as he wrote in 1270, or eighty years before Schwartz, the German monk's ill acquired reputation may be stripped from him without hesitation. The passage in Bacon is as follows: a Ex hoc ludicro puerili quod fit in multis mundi partibus, scilicet, ut instrumento facto ad quan titatem pollicis humani, ex violcntia salis qui salpetrx vocatur, tam horribilis sonus nascitur." Again, " In ruptura tam modicae rei, scilicet, modici pergameni, quod fortis tonitrum excedere rugitum et corrusca tionem maximam sui luminis jubar excedit." It is very plain here that Bacon is describing a cracker or squib used by boys, and common in many parts of the world. But we need trace the history of this art no farther. Time, in complicating the movements, in add ing new combinations, and in discovering ingredients, before unknown, 5U ppliuble. to the production of parti cular effects, has now rendered it an extensive art, which it will nevertheless not be difficult to arrange under a few simple principles.
Of the Ingredients used in Pyrotechnic composition.
These may be divided into the essential, or those by which the fire is produced, and the incidental, by which it is modified. The first of these include nitre, sul phur, charcoal, and certain resinous and oily substances; among the latter, the metals are the chief. We shall examine then) in order, with such remarks on their varieties or preparation as are necessary. For want of such discrimination, there is often much difficulty in understanding the popular receipts, while failures are also not unfrequent.
NITRE.—This substance, the soul of all pyrotechny, is often described under two names, viz. saltpetre and sal prunella. This latter is merely fused nitre; and as that salt contains no water of crystallization, there is no difference whatever between it and saltpetre which has been carefully dried. There is, however, an objection to its use, which must be pointed out. In a high heat, nitre is decomposed with the loss of its acid. If, therefore, in the fusion of the sal prunella the heat should accidentally have been raised too high, the consequence is the presence of a portion of the alkali, which, by afterwards absorbing water, renders the compositions into which it enters liable to become damp, and thus to lose their good qualities. To pre vent this consequence, so particularly destructive to all the compositions into which iron enters, the saltpetre should not only be thoroughly dried, but carefully pu rified, that it may be freed from the nitrates and mu Hates of lime, in particular; salts which attract much moisture. This is to be done only by careful and re peated crystallization; nor should any nitre be used which nay not previously been tested with a solution of subcarbonate or potash, and with that of nitrate of mer cury. To stand these without having any marks of precipitation, is a proof of that absolute purity which is most essential.