GUNNERY GUNPOWDER. 



589 



dtfend any position ; he must have an accurate ac- 

 quaintance with the science of fortification ; but 

 especially he must be practically skilled in throwing 

 up batteries and other field-works, so that he may be 

 able, by disposing his artillery before or within a 

 strong place, to assist the engineer most effectually 

 in its attack or defence. Besides, the artillerist has 

 often the regulation of the lights, and other signals, 

 in time of war, of the fire-works in peace, &c. All 

 this must be learned by experience, and by the study 

 of auxiliary sciences. Mathematics (particularly the 

 doctrine of curves, to calculate the path of the balls), 

 physics and chemistry are very necessary, in order 

 to understand the effect of powder, and the manufac- 

 turing of ammunition, as well as that of all kinds of 

 fire-works. A knowledge of mechanics is, also, very 

 useful, for understanding the theory of carriages, for 

 moving' large loads, when necessary, and on many 

 other occasions. 



On the principles of dynamics it can be easily 

 shown that, were there no resistance to the motion 

 of a bullet in consequence of the air, the path of the 

 ball would be that curve denominated the parabola. 

 Were it not, then, for the resistance of the atmo- 

 sphere, it would be easy to determine with precision 

 the range of a ball, of a given weight, discharged with 

 a given force, in a certain direction. It was for a 

 long time considered that the resistance of the air 

 was so trifling as not to be worthy of being taken 

 into account ; and, accordingly, the principles of 

 gunnery were taught upon the parabolic theory. 

 Mr Robins, Dr Hutton, and others, made extensive 

 experiments, with a view to determine the amount of 

 the resistance of the air. In fig. 13, plate LXI., 

 a vessel is represented as passing through a strait, 

 between two batteries, amid a discharge of artillery. 

 The battery at A is much higher than the hull of the 

 vessel, and, accordingly, the cannon is inclined so 

 that its muzzle is lower than its breech. It is so 

 situated in order that the bullet which it discharges 

 may strike the hull of the vessel. But the axis of the 

 gun is not pointed directly at the spot where the 

 ball is intended to strike ; for as, on account of the 

 action of gravity, the ball in its passage from the 

 gun to the object, is continually drawn towards the 

 earth, it will therefore describe a curve, as shown 

 by the curve line AB. Were the ball to move in a 

 straight line, as the gun is now pointed, it would 

 pass over the hull of the ship and strike the opposite 

 battery at C. The cannon, at tnis last station, is 

 also shown as discharging a bullet at the vessel, and 

 it is made to point a little upwards in order to com- 

 pensate for the continual falling of the ball during 

 its flight. The vessel is shown as discharging a gun 

 at K so as to strike the battery at C ; but the elevation 

 of the piece not being sufficient, the bullet is shown 

 as having struck the water at F, and as having risen 

 again at G, exhibiting an appearance similar to what 

 is called ducks and drakes, when a stone is thrown at 

 a small angle to the surface of the water. From 

 these statements it will be easy to perceive, that very 

 nice adjustment is necessary in giving the requisite 

 angle of elevation or depression to the gun, and of 

 proportioning the charge of powder, so that the ball 

 shall be sent to the proper distance and in the proper 

 direction. Theory and experiment have furnished 

 rules for this purpose, of the most approved of which 

 the following is a synopsis. 



As the square root of the weight of the shot is to 

 the square root of double the weight of powder, 

 (both in Ibs.) so is 1600 to the velocity of the shot at 

 the commencement in feet per second. Multiply 

 the square root of the diameter of the ball, in inches, 

 by 175-5, and for shells by 147'3, the product is the 

 velocity of it, at the end of the flight, i. e., the terminal 



velocity. The horizontal range is found by multiply- 

 ing twice the height to which the ball would be car- 

 ried, by the sine of double the angle of elevation ; 

 or the range of any one elevation is to another, as 

 twice the sines of these elevations are to each other, 

 and the ranges are nearly proportional to the charges. 



GUNPOWDER is a mixture of saltpetre, sulphur, 

 and charcoal. If we may believe the relations of 

 the missionaries, and the reports of the Chinese his- 

 torians, the Chinese were first acquainted with the 

 application of gunpowder. Perhaps it proceeded 

 from them to the Arabs ; for, in 1331, the Moors 

 used it in their operations before Alicant, and cer- 

 tainly in 1342, at Algesiras; in 1250, the Arabs 

 probably used a mixture similar to gunpowder before 

 Damietta, and perhaps also in a naval engagement 

 in the year 1085. Among the Europeans, the traces 

 of this invention are still more ancient ; for the Greek 

 fire, which was first employed in 668, must liave, at 

 least, contained saltpetre mixed with pitch, naphtha, 

 &c., since it was customary, by means of it, to hurl 

 stones from metallic tubes. The first information of 

 the knowledge of the Europeans with regard to the 

 chemical mixture of powder, is found in the ninth 

 century, in a book composed by Marcus Gracchus, 

 preserved in the university of Oxford, which also 

 accurately explains its composition. Roger Bacon 

 (who died in 1294) was likewise acquainted with the 

 power which saltpetre has, when set on fire, of pro- 

 ducing a thundering report. The discoverer of the 

 power of powder, when confined and set on fire, of 

 propelling heavy bodies, was according to common 

 report, Berthold Schwartz, a monk, who is said to 

 have lived at Mayence, between 1290 and 1320. He, 

 in some of his experiments in alchemy, had put the 

 mixture into a mortar, and, having accidentally 

 dropped into it a spark of fire, to his astonishment, 

 saw the pestle fly off into the air. Other traditions 

 attribute this invention to Constantino Antlitz of 

 Cologne (see De Boucher's Memoir e sur r Origins de 

 la Poudre d Canon). However this may be, powder 

 was scarcely applied to military uses before 1350, 

 and the accounts of the use of cannons in the battles 

 of Crecy (1346), Poictiers, and still earlier engage- 

 ments, have arisen from the various significations of 

 the word cannon. In 1356, powder is mentioned hi 

 the accounts of the treasury of Nuremburg ; in 1360, 

 the house of assembly at Lubeck was burned by the 

 imprudence of the powder manufacturers ; and, in 

 1365, the Margrave of Misnia had pieces of artillery. 

 In the course of a few years afterwards, it was known 

 over all Europe. Thus the first traces of this inven- 

 tion would appear to be found in Germany ; other 

 nations, however, have put in their claims to this 

 honour. 



The proportion of the ingredients in the composi- 

 tion of gunpowder, is different in different countries : 

 in the Prussian powder-mills, 75 parts of saltpetre, 

 11^ parts of sulphur, and 13 parts of charcoal are 

 used ; but in the French mills, 75 parts of saltpetre, 

 12| of coal, and 125 of sulphur. In the manufacture 

 of (his article, which is carried on in very different 

 ways, much depends upon the goodness of the ingre- 

 dients. The crude saltpetre is broken up, moistened, 

 and exposed to the action of a slow fire, continually 

 skimmed and violently agitated, till all the moisture 

 evaporates, and the saltpetre remains in the form of 

 a fine powder. The sulphur is pulverized after hav- 

 ing been well purified. The charcoal is that derived 

 from the alder or any other soft wood or bushes, as, 

 for example, hemp stalks, which are burned with 

 great care in a confined room, and reduced to a fine 

 powder. These three ingredients are then moistened, 

 brought under a stamping, or more commonly a roll, 

 ing mill, where two metallic, or, which are better, 



