Mr. Hallam, referring to the authority of an Arabic author, infers that there is no question that the knowledge of gunpowder was introduced into Europe through the means of the Saracens, before the middle of the 13th century; and no doubt its use then was more for fireworks, than as an artillerist projectile force. There is good evidence, too, that the use of gunpowder was introduced into Spain by the Moors, at least as early as the year 1343. Now, as Roger Bacon is known to have been an Arabic scholar, it is not at all unlikely that he might have become acquainted with the mode of making the composition, and also with its most remarkable properties, by perusing some Arabian writer with whom we are at present unacquainted. This invention, by which the personal barbarity of war has certainly been diminished, is, when considered as a means of human destruction, by far the most powerful that skill has ever devised, or accident presented; acquiring, as experience shows us, a more sanguinary dominion in every succeeding age, and subserving all the progressive resources of science and civilization for the extermination of mankind: which, says Mr. Hallam, “appals us at the future prospects of the species, and makes us feel, perhaps, more than in any other instance, a difficulty in reconciling the mysterious dispensation with the benevolent order of Providence.” The composition of gunpowder, as regards the proportions of the ingredients, has not undergone any material alteration; the chemical proportions of the ancients being nearly those of the present day. Gunpowder is an explosive propellant compound, consisting of saltpetre or nitre, charcoal, and sulphur. The terms, _explosive_ and _propellant_, are not here used as synonymous--they are not convertible; for a chemical mixture may possess the _explosive_ power in a much higher degree than the _propellant_: fulminating gold, silver, and mercury, are dreadfully explosive; but they have not the same projectile force, nor can they be used as a substitute for it. Several experiments have been made with compounds of this nature, but the result is the reverse of what might be expected. Nothing can resist the exceeding intensity of the action of fulminating powder; a shot, when fired in this way, is not projected as by gunpowder, but is split into fragments by the velocity of its explosion, as we shall hereafter have occasion to show.