Part 198

2. Spaces equally run through in the same or equal times, are to one another as the velocities with which they are run through, and conversely.

3. Spaces run through are in the same proportion to one another, as their times multiplied into their velocities, and conversely.

4. A body urged by two distinct forces in two different directions, will in any given time be found at the point where two lines meet that are drawn parallel to these directions, and through the points to which the body could have moved in the same time, had these forces acted separately.

5. The velocities of bodies, which by the action of gravity begin to fall from the rest, are in the same proportion as the times from their beginning of their falling.

6. The spaces run through by the descent of a body which began to fall from rest, are as the squares of the times, from the beginning of the fall.

7. The motion of a military projectile is in a curve.

GUN-powder, a composition of nitre, sulphur, and charcoal, well mixed together and granulated, which easily takes fire, and expands with amazing force, being one of the strongest propellents known.

Gun-powder.--Proportions of the different ingredients for making gunpowder, by different powers in Europe:

+--------+----+------+-------+-------+------+-------+ | |Eng.| Fran.|Sweden.|Poland.|Italy.|Russia.| +--------+----+------+-------+-------+------+-------+ |Nitre | 75| 75 | 75 | 80 | 76¹⁄₂| 70 | |Sulphur | 10| 9¹⁄₂| 9 | 8 | 12¹⁄₂| 11¹⁄₂| |Charcoal| 15| 15¹⁄₂| 16 | 12 | 12¹⁄₂| 18¹⁄₂| +--------+----+------+-------+-------+------+-------+ | Pounds| 100|100 | 100 | 100 | 100 | 100 | +--------+----+------+-------+-------+------+-------+

GUNPOWDER. This well known powder is composed of seventy five parts, by weight, of nitre, sixteen of charcoal, and nine of sulphur, intimately blended together by long pounding in wooden mortars, with a small quantity of water. This proportion of the materials is the most effectual. But the variations of strength in different samples of gunpowder are generally occasioned by the more or less intimate division and mixture of the parts. The reason of this may be easily deduced from the consideration, that nitre does not detonate until in contact with inflammable matter; whence the whole detonation will be more speedy, the more numerous the surfaces of the contact. The same cause demands, that the ingredients should be very pure, because the mixture of foreign matter not only diminishes the quantity of effective ingredients which it represents, but likewise prevents the contacts by its interposition.

The nitre of the third boiling is usually chosen for making gunpowder, and the charcoal of light woods is preferred to that of those which are heavier, most probably because this last, being harder, is less pulverable. An improvement in the method of making the charcoal has lately been adopted, which consists in putting the wood, cut into pieces about nine inches long, into an iron cylinder laid horizontally, closed at one end, and furnished with small pipes at the other, that the pyroligneous acid and carburetted hidrogen may escape, and thus exposed to the heat of a fire made underneath. It is said, this charcoal improves the strength of gunpowder so much, that only two thirds of the old charge of gunpowder for ordnance are now used in our navy. The requisite pounding of the materials is performed in the large way by a mill, in which wooden mortars are disposed in rows, and in each of which a pestle is moved by the arbor of a water-wheel: it is necessary to moisten the mixture from time to time with water, which serves to prevent its being dissipated in the pulverulent form, and likewise obviates the danger of explosion from the heat occasioned by the blows. Twelve hours pounding is in general required to complete the mixture; and when this is done, the gunpowder is in fact made, and only requires to be dried to render it fit for use.

Proofs of powder.--The first examination of powder in the British mills, is by rubbing it in the hands to find whether it contains any irregular hard lumps. The second is by blasting 2 drams of each sort on a copper plate, and in this comparing it with an approved powder; in this proof it should nor emit any sparks, nor leave any beads or foulness on the copper. It is then compared with an approved powder, in projecting an iron ball of 64 lbs. from an 8 inch mortar, with a charge of 2 ounces. The best cylinder powder generally gives about 180 feet range, and pit 150; but the weakest powder, or powder that has been redried, &c. only from 107 to 117 feet.

The merchants’ powder, before it is received into the government service, is tried against powder of the same kind made at the royal mills; and it is received if it gives a range of ¹⁄₂₀ less than the king’s powder with which it is compared. In this comparison both sorts are tried on the same day, and at the same time, and under exactly the same circumstances.

The proof of fine grained, or musquet powder, is with a charge of 4 drams from a musquet barrel, to perforate with a steel ball a certain number of ¹⁄₂ inch wet elm boards, placed ³⁄₄ inch asunder, and the first 39 feet 10 inches from the barrel: the king’s powder generally passes through 15 or 16, and restoved powder from 9 to 12. The last trial of powder is by exposing about 1 pound of each sort, accurately weighed, to the atmosphere for 17 or 18 days; during which time, if the materials are pure, it will not increase any thing material in weight, by attracting moisture from the atmosphere.

In this exposure 100 lbs. of good gunpowder should not absorb more than 12 oz. or somewhat less than one per cent.

Different modes of trying gunpowder have been adopted. A ready one is, to lay two or three small heaps on separate pieces of writing paper, and fire one with a red hot wire. If the flame ascend quickly, with a good report, leaving the paper free from white specks, and not burnt into holes; and at the same time the other heaps be not fired by the sparks, the powder is well made, and the ingredients are good.

There are experiments which seem to show, that gunpowder is stronger in the fine impalpable form, than when granulated. This appears to be true with regard to gunpowder originally made, or pounded till it assumes that form; but it may be doubted, whether it have any foundation in general, or indeed that the greater strength depends at all upon this form.

British Powder Marks.--The different sorts of powder are distinguished by the following marks on the heads of the barrels.

N^{o.} ¹⁄₂} } L G }Cylinder} ----- } } N^{o.} 2} } S G } Cylinder}Marked in Red. ----- } } N^{o.} 3 } } F G } Cylinder} ----- } }

~S A~--The dust from N^{o.}3, and F G cylinder.

~R A~--For rifle arms.

⁴⁄₇ Cylinder}mixed--Marked white L G. ³⁄₇ Restoved}

L G or F G in blue, is powder made of pitcoal.

/ \ / \ {N^{o.} ¹⁄₂ L G}Marked in yellow, is restoved. |R S| {N^{o.} 3 F G} \ / \ /

This red L G, F G, or S G, denotes powder entirely made of the cylinder charcoal, and is that which is now always used on service. The white L G being a mixed powder, is not so uniform as the other, and is therefore generally used in filling shells, or for such other purposes as do not require much accuracy. All powder for service is mixed in proportions according to its strength, so as to bring it as much as possible to a mean and uniform force.

French Gunpowder.--The French proof ball is of brass, and weighs 60 lbs. French: the diameter of the mortar 7 inches 9 points, or ³⁄₄ of a line, and has one line of windage. The chamber holds exactly 3 ounces; and their best powder must give a range of 90 toises, and their restoved powder a range of 80 toises, to be received into the service. But the powder they now make, when new, will give range of 100 and 120 toises; and Mr. Lombard calculates all his tables from experiments made with powder giving 125 toises with the eprouvette. The above dimensions and weights are all of old French standard.

Invention of GUN-powder, is usually ascribed to one Bartholdus Schwartz, a German monk, who discovered it about the year 1320; it is said to have been first used in war by the Venetians against the Genoese in the year 1380. Thevel says its inventor was one Constantine Anelzen, a monk of Friburg. Peter Mexia says it was first used by Alphonsus XI. king of Castile, in the year 1342. Ducange adds, that there is mention made of this powder in the registers of the chambers of accounts of France, so early as the year 1338; and friar Bacon, expressly mentions the composition in his treatise De Nullitate Magiæ, published at Oxford in the year 1216. Some indeed are of opinion, that the Arabians or the latter Greeks were the first inventors of gunpowder, about the middle ages of our æra; because its Arabic name is said to be expressive of its explosive quality.

Considerable improvements have lately been made in the composition of gunpowder by the Chinese.