57 



GUNPOWDER. 



GUTTA-PERCHA MANUFACTURE. 



Straith. On PoiH.teati<m aitd ArtiBrrg, reviled by Cook utd Hyde ; 

 Trtnlue on Arlillrry for f g, 11. Academy, HWwK-A, by Captain 

 Boxer. R A > 



GUNPOWDER, composition with the explosive power of which 

 every one in more or lea acquainted. The date of its invention in 

 iBvolvvd in obscurity. It baa been laid that it waa u*ed in China IM 

 early as the your A.D. 86, and that the knowledge of it wu conveyed to 

 it* from the Arab* on the return of the Cnuaden to Europe ; that the 

 Aral* made uw of it at the siege of Mecca in 690 ; and that they 

 derived it from the Indiana. 



Sir Oeorge Staunton observe* that " the knowledge of gunpowder in 

 China and India aeon* coeval with the most distant historic event*. 

 Ami ng the Chineee it baa at all times been applied to useful purposes, 

 .is blasting rocks, *c., and in the making of fireworks ; Although it has 

 not been directed through strong metallic tube*, as the Europeans did 

 soon after they had discovered it." 



Roger Bacon has been supposed to allude in an enigmatic way to the 

 composition and explosive force of gunpowder; and about 1886 

 BerthoM Schwartz, a monk, is said to have also discovered the mode 

 of manufacturing it 



Gunpowder consists of a very intimate mixture of nitre, or nitrate 

 of, potash, charcoal, and sulphur. Theoretically, the proportions of 

 thw* ingredients ought to be as follow : 



1 equivalent nitrite of potiuh 

 3 equivalent! carbon 

 1 iquivalcnt sulphur . 



Equivalent 



135-11 



Per-cenuge 



amount. 



74-S 



18-3 



11-0 



100-0 



It is remarkable that tin-to proportions have been nearly attained 



utnpirically in the best descriptions of gunpowder, as seen from the 

 following table : 



English. French. Prussian. 



Nitrate of po'.asU . . . 75-0 74-0 7S-0 



Charcoal 15-0 13-5 ' 13-5 



Sulphur 10-0 12-J 11-3 



100-0 



1000 



100-0 



The suddenness and intensity of the explosion depends upon the 

 amount of sulphur, which is on this account increased in blasting- 

 powder, the composition of blasting-powder being : 



Mlrate of potash 

 Charcoal . 

 Ett'.jhur 



6$ 

 19 



20 



100 



This large amount of sulphur would cause the corrosion of fire-arms, 

 and consequently for war and sporting purposes the quantity is 

 diminished. 



The ingredient* must be of the greatest attainable purity ; and the 

 nitre is fused before use, in order to expel the last portion of water, 

 which seems however scarcely necessary for any other purpose tli.m 

 the exact ascertainment of its quantity, inasmuch as the mixture is 

 subsequently wetted. The charcoal, either of alder, willow, or dog- 

 wood, is prepared, not in the usual method, but in iron retorts; and 

 the sulphur is the volcanic kind imported from Sicily, and is refined 

 by melting or subliming. 



When the several ingredients arc prepared, they are separately ground 

 to a fine powder, and mixed in the proper proportions. The compo- 

 sition is then sent to the gunpowder-mill, which consists of two stones 

 vertically placed, and running on a bed-stone. On this bed-stone the 

 composition is spread, and wetted with as small a quantity of water as 

 will, together with the revolutions and weight of the runners, bring it 

 into a proper body, but not into a paste. After the stone runners 

 hare made the proper number of revolution* over it, and it is in a fit 

 state, it is taken off and sent to the corning-house to be corned or 

 grained ; here it is firrt pressed into n hard and firm body, broken into 

 small lumps, and the powder is then grained by these lumps being put 

 into sieve*, in each of which is a flat circular piece of lignum vita?. 

 The sieves are made of parchment skins, having round holes punched 

 through them ; several of these sieves are fixed in a frame, which by 

 machinery has such a motion given to it a* to make the lignum vitn 

 runner in each sieve go round with velocity sufficient to break the 

 lumps of powder, and force them through the sieves, forming grains of 

 several sizes. The grains are separated from the dust by proper sieved 

 and reel* ; they are then hardened, and the rougher edges taken off hy 

 bring run a sufficient length of time in a close reel, which ha* i> 

 circular motion given to it. 



The gunpowder, thus corned, dusted, and reeled (which is called 

 glazing, a* it put* a small degree of gloss on it), i* sent to the stove 

 and dried ; care being taken not to raise the heat so as to dissipate the 

 iiilphur. The heat is regulated by a thermometer. 



A powder-mill is a slight wooden building with a boarded roof. 

 Only about 40 or 50 pounds of composition are. worked at a time, .< 



an explosion will sometimes happen from the runners and bed-stone 

 coming in contact, and from other cauM*. Theae mills are worked by 

 water or horn*. 



The theory of the action of gunpowder is this : That particle of it 

 on which a spark falls is immediately heated to the temperature of 

 ignition ; the nitre Is decomposed, Ha oxygen combine* with the char- 

 coal, whilst the sulphur unite* with the potassium of the nitre, 

 thus: 



KONO, + 8 + SO = US + K !- SCO, ; 



Mire. 



>'.-. 

 polanium. 



< a .. 

 icid. 



this combination extricate* a* much heat as is sufficient to inflame 

 successively, though rapidly, the remaining mass. The cause of the 

 expansive force of gunpowder i* the production of carbonic acid and 

 nitrogen gases ; and these being liberated at a very high temperature, 

 the effect is greatly increased. Gunpowder i* thus expanded 

 4000 times at the moment of explosion. According to Gay-Lussac, 

 every 100 volumes of the gas produced consist of 53 parts of carbonic 

 acid, 5 of carbonic oxide, and 42 of nitrogen. The carbonic oxide i 

 formed by an excess of charcoal, as in the English powder. The solid 

 remaining after the combustion is principally gulphuret of potassium ; 

 but it in evident that the proportions and nature both of the gaseous 

 and solid products of the combustion must depend on the composition 

 of the gunpowder. 



Gunpowder may be fired by the electric spark, and by percussion. 

 If it be mixed with powdered glass, or any other hard substance, and 

 struck with a heavy hammer on an anvil, it almost always explodes. 

 It readily bums under water, and by using a slowly burning powder, 

 such as squibs are filled with, may be inflamed in a tube of copper, 

 and the gaseous products of the combustion may be collected in a glass 

 jar filled with and inverted in water in the pneumatic trough. 



In ascertaining the goodness of gunpowder, which is done by deter- 

 mining its strength, an eprouvetle is employed to measure it* projectile 

 force. Thi* is a small strong barrel, in which a given quantity of the 

 powder is fired, and the comparative expansive force is measured by 

 the action exerted on a spring or weight. 



A ready but not a very accurate way of analysing gunpowder is to 

 wash out the nitre of a given weight by water, weigh the residue, which 

 will show the quantity of nitre dissolved, and boil it in a solution of 

 potash ; the residue, after washing and drying, will be the charcoal, 

 and its weight taken from that left after the action of the water will 

 show the quantity of sulphur dissolved by the potash. 



GUNTER'S LINK ; GUNTER'S SCALE. [SLIDING SCALE.] 



OUTTA-PEUCHA MANUFACTURE. Few substance* applicable 

 to the aitw have sprung up so rapidly into extensive use as gutta- 

 percha. Twenty years ago it wag wholly unknown in Europe. In 

 1842, Dr. Montgomerie, a resident at Singapore, looking at a native 

 wood-cutter while at hi* employment, waa struck with the peculiar 

 appearance of the handle of the axe ; it waa formed of some material 

 not familiar to him. On inquiry, Montgomerie found that the sub- 

 stance of which the handle was made could be. moulded into any form 

 l>y dipping it into boiling water until it became soft, and that it 

 speedily resumed its tough and rigid condition when removed from the 

 water. He next ascertained that the substance resembled caoutchouc 

 in this : that both exude from between the bark and the wood of 

 certain forest trees. The natives around Singapore called it by a 

 name which, with an addition, soon became Oatta-percha. Or. 

 Montgomerie sent specimens, in various stages of preparation, to the 

 Society of Arts in London. Independently of Dr. Montg< 

 however, a discovery ..f the tree and tliu gum was also made l>y Mr. 

 Thomas Lobb, who in 18 12-3 was travelling in the east a* agent for 

 Messrs. Veitch, of Exeter. Those enterprising botanists and florists 

 employed their agent to procure new or rare plant* for transnuV 

 England ; and while on his rambles, Mr. Lobb acquired a knowledge of 

 gutta-percha, a* a gum which exudes from trees. When the small 

 pieces reached the Society of Art*, Mr. Whishaw and Mr. Hancock 

 experimented on them, with a view to discover their useful qualities ; 

 pipe*, lathe-bands, and sheet* were soon produced in a rough way, and 

 a baai* wa* obtained for an important addition to our materials for 

 manufacture*.* 



It gradually became ascertained that the gutta-percha tree abound* 

 in thu Malayan Peninsula, in Borneo, and in various island* of the 

 Eutorn Archipelago. The chiefs of those islands, or portions of 

 contrive to obtain a profit out of the trade ; but there is *t 

 left to allow remuneration to all rise concerned. For about sixteen 

 year* the tree* have eagerly been cut down as a mean* of obtaining 

 the gum ; and however this may be regretted as a wasteful proceeding, 

 it nevertheless cleared the ground for future settlers in those islands, 

 ins are, however, teaching the native* how to obtain the sap 

 without cutting down the tree. The tree belongs to the Sapota*xo*t 



Credit has been given. In mot of tht technological and wlrntiflo publica- 

 tion", to Dr. Hontgoroerie, an the pcraon who Brut introduced (in the y 

 gutia-percha to the attention of European*. In ISA*, however, a claim 

 was put in for Don Jose d'Alim ida ; who, In 1842, bought some of the gum from 

 the native* cf Singapore, brought It to England, gave a portion to a fellow - 

 piisn|tr, and sent the remainder to the Knyitl Anlatie Society. 



