rVIIOPHONE 



PYROTECHNY 



Pyrophonr, also called Flame-organ, is a 

 musical instmment invented about IsT.'i I iv Kugene 

 Kaitner (I8A2-K2) of 1'aiis. in which the inn~ir.il 

 toneit are produced by flame* of hydrogen gas hum 

 ing in tul*'* of different si/es ami length-, arranged 

 somewhat as in an onlinary organ. 



PyrophOFMS (from the Gr. j>yr, 'fire,' and 

 Aerii, ' I bear ') is a term applied to any sulwtances 



which take fire from the rapidity with which they 

 are oxidised. If iron, colmlt, or nickel lie reduced 

 by hydrogen from it- oxide at a low red heat, it is 

 obtained in a state of such extreme division as to 

 become incandescent liy tin- oxidising action i)f the 

 atmosphere ; and the tendency to rapid oxidation 

 u mpch increased by the interposition of some 

 infusible matter, as a little alumina or magnesia, 

 between the particles of the oxide. This U prob- 

 ably due to the cohesion of the minute particles 

 ill tin- reduced metal being thus mechanically pre- 

 vented, and the access of air to the surface of each 

 particle being thus facilitated. If tartrate of lead 

 be heated in a tube till the organic portion becomes 

 charred, the metallic leail is minced to a state of 

 extreme subdivision, and usually taken lire when 

 poured into the air. If finely powdered sulphate 

 of potash be mixed with half its weight of lamp- 

 black, and heated in a covered crucible, the sulphate 

 is reduced to sulphide of potassium, which remains 

 in a finely-divided state, mixed with the excess of 

 carbon, and takes fire spontaneously in the air from 

 the rapid absorption of oxygen. These are amongst 

 the best examples of pyropliori. 



Pyrosis. See INDIGESTION. 



Pyrosona, a genus of compound or colonial 

 Tunicate*, sometimes called ' lire- flames ' on 

 account of their brilliant phosphorescence. The 

 colonies are hollow cylinders, o|ien at one end, and 

 the walls are formed of hundreds of individuals. 

 These have inhalent apertures on the exterior, 

 while their exhalent apertures open into the cavity 

 of the cylinder, thus producing a gentle current, by 

 means of which the colony is slowly propelled 

 through the water with the closed end foremost. 

 Several species occur in the warmer seas, and /'. 

 mgantfum is from 2 to 3 feet long. See ASCIDIANS, 

 PHOSPHORESCENCE. 



Pyroterhny, the art of making fireworks, is 

 of unknown antiquity. It was practised amongst 

 the Chinese from very early times, and has attained 

 with them so much perfection that the beauty and 

 ingenuity of their devices have often been admired 

 by Europeans. Fireworks, as the name U now 

 understood, were hardly known in Kurope until 

 the nature of gunpowder became known, and for a 

 long time only very simple pyrotechnic contrivances 

 were nsed. 



The compositions employed for most kinds of 

 fireworks are of the nature of gunpowder. That 

 is to say, the mixtures of which they are, mode con- 

 tain combustible or oxidisahle suiwtanees, along 

 with bodies available for their rapid combustion, 

 since these latter contain large quantities of oxygen. 

 The most frequently employed combustible 

 materials are carbon (charcoal) or some compound 

 of carbon, such as sugar or gum, and sulphur or a 

 compound of this element, such as sulphide of 

 antimony. Kuch )>odies as charcoal and sulphur 

 burn slowly in common air, because its oxygen is 

 largely mixed with nitrogen, which does not sup- 

 |Mirt combustion : but when they are compounded 

 with nitrates and chlorates the store of oxygen in 

 these salts being given off by heat enable* the lire 

 work ooini*i-itjon to burn at a more or less rapid 

 rate whenever a spark is applied to it. It is not 

 desirable, however, to have too sudden a union of 

 conibiiMible mutter with oxygen, hence violent 

 explosives, like nitro glycerine, are unsuitable for 



showing coloured or brilliant flames. The two 

 most iin|Hiitiint oxidising ingredients used in fire- 

 work coni|iositions are nitrate ami chlorate of 

 potash. Iron, in the form of cast-iron or steel, and 

 in a state of line division, is a frequent ingredient 



in fireworks, and to s e extent the powder or 



filings of antimony, xinc, magnesium, and copper 

 are also employed. When the particles of these 

 metals are highly heated they produce sparks and 

 scintillations of different colours. A few sub- 

 stances, such as sand and sulphate of potash, are 

 used to modify the rate of combustion. 



Variety of colour is much studied in the produc- 

 tion of fireworks, as it contributes greatly to their 

 lieniity. The colours usually seen are those given 

 by simple metals when burned. Compounds of the 

 metals form part of the mixtures, and these an- 

 reduced to the metallic condition in a suite of very 

 fine division by contact with the earlioii present in 

 the hot mass. A yellow colour is one of the most 

 easily managed, any of the common compounds of 

 sodium producing it. Copper gives a green colour 

 when burned in a hydrogen flame, which changes to 

 blue in the presence of a little free chlorine; so 

 that when this metal is used for green some sub- 

 stance containing hydrogen is added, and when 

 employed for blue, calomel (one of the chlorides of 

 mercury) is put into the mixture. Nitrate of 

 barium is also employed for green. Salts of 

 strontium give tine crimson tints, calcium com- 

 pounds a red, and lithium cat-Inmate (a costly 

 substance) a purple red. Among the sulistances 

 nsed to produce white colours are sulphide of anti- 

 mony and sulphide of arsenic. 



The cases which contain the firework composi- 

 tions are carefully mode of paper or pasteboard, or 

 both, pasted in layers. They are usually cylindrical 

 in shape, and the proportion of length to diameter, 

 and the size of openings for the escape of the 

 burning mixtures, are matters of importance. So 

 also is the proper mechanical construction of the 

 framework of rotatory fireworks. Touch-paper, 

 prepared with a solution of nitrate of potash in 

 alcohol, is used for capping squibs, crackers, and 

 indeed for all kinds of fireworks; quick-match of 

 cotton-wick, which bos lieen saturated with gun- 

 powder, gum, and other ingredients, connects the 

 parts of complicated designs; and portfires, small 

 pencil-like articles filled with saltpetre, sulphur, 

 and gunpowder, are used to fire the touch-paper 

 eappings. 



The simpler kinds of fireworks include squibs, 

 crackers, gerlw, [Ionian candles, stars, sparks, 

 maroons, theatre-fires, Bengal lights, \c. A'ym'ft* 

 are small stout paper tubes filled with grained 

 powder, to which a little charcoal, sulphur, and 

 steel filings are sometimes added, a sufficient quan- 

 tity of bursting powder being put in to cause a 

 slight explosion at the end when fired. Crackers 

 consist of a tube bent into folds, and containing 

 meal-powder, charcoal, sulphur, saltpetre, and 

 sometimes iron filings in varying proportions. The 

 folds are tied by a cord ; and on a cracker being 

 fired a report is given at every tnrn of the tube. 

 Serpents are tubes, some of which have a choke in 

 the middle. When fired they take a zigzag direc- 

 tion, and give out a hissing noise. Gerbi consist 

 of a straight cylindrical case filled with a composi- 

 tion which produces a bright sparkling jet of fire 

 somewhat in the form of a waters|Hiut. They 

 sometimes contain coloured stars. Human candid 

 have a resemblance to gerbs. In filling them stars 

 are placed at intervals along the tulie between 

 layers of the composition. Stars are of different 

 kind-, such as simple stars, tailed stars, and 

 pointed stars. Simple stars consist of saltpetn 

 sulphur, and fine gunpowder made into a past" 

 ball with gum ana spirit* of wine, and dried. 



