When Musschenbroek (not a superstitious soldier, but an inductive philosopher) first discovered the Leyden Phial, he declared he would not take a second shock for the kingdom of France; and yet we well know that a schoolboy would not now be frightened at a much more powerful shock than he then experienced. Want of familiarity with a phenomenon, and ignorance of its proximate cause, will ever make it terrible. We cannot see any thing terrible in a sky-rocket, because we have been early influenced by those on whom we rely to regard it as an amusement; but had they brought us up in fear of it--had they magnified these accounts, having some foundation in fact, as to its destructive power, we may well understand what effects of terror it would produce. Thus regarded, the _ignotum pro magnifico_ appears quite sufficient to explain the narrated effects of the Greek fire. But there was also another reason--viz. that all results, not of continual occurrence, and within the range of ordinary experience, were attributed to magic, and consequently spread a terror far disproportioned to the real effects; for this reason, the means of producing then were prohibited by the hierarchy, and, as they gradually acquired a more extensive use, were then only permitted against the enemies of the religion of the people who used them; hence the expression so frequent in the Arabian receipts, "You shall burn your adversary for the service of God;" and similar language is used by the Christian writers, when similar compositions became used by Christian warriors. A narration, taken from the Sieur Joinville's History of St Louis, will place before our readers the contemporaneous description of the effects of the pyrotechny of the Arabs. The following is the account of Joinville of one of the skirmishes of St Louis on the borders of the Nile. We should premise that Turk is the term generally applied by Joinville to all Mussulman soldiers; and though the army was generally recruited from Turkish slaves, yet the country was possessed by Arabs, and the language and arts were theirs.