04 



COMBRETUM COMBUSTION. 



teen or twenty feet. Its bark and fruit possess power- 

 ful astringent properties, and are much used by the 

 Hindoos in arts and manufactures. The flowers are 

 also used in powder, to check bowel complaints. The 

 bark of Terminalia alata is met with in the Indian 

 bazaars. It is of a reddish brown colour, has a strong 

 astringent taste, and is used in Ceylon in febrile cases. 

 The juice of the leaves is poured into the ears for the 

 purpose of allaying the pain of earach. The bark also 

 dyes black, and the wood is used in building, and in 

 the formation of boats. The kernel of the fruit of 

 Terminalia latifolia is edible, and a decoction of the 

 root of the plant is exhibited in Jamaica in cases of 

 diarrhoea. The kernel of Terminalia Catappa has the 

 taste and virtues of the almond. It also yields an oil 

 which is used as an article of food. The tree supplies 

 valuable timber. Its bark and leaves yield a black 

 pigment, with which the Indians dye their teeth, and 

 which is sometimes used in the formation of Indian 

 ink. The fruit of Terminalia citrina is about the size 

 of a French plum, and is made into a pickle. Ter- 

 minalia angiistifolia furnishes a resinous substance, 

 similar to benzoin. 



Laguncularia racemosa is one of the plants called 

 mangroves in Brazil, and is used in Rio Janeiro for 

 tanning. The bark of Sucida Buceras, known in the 

 Antilles by the name of French oak, is also used for 

 a similar purpose. 



The genera Combretum and Quisqualis furnish some 

 of the most splendid climbing plants of the tropics. 

 When suspended from the trees in these regions, their 

 white, crimson, and yellow flowers have a peculiarly 

 showy and striking appearance. 



COMBRETUM (Linnaeus). A fine genus of 

 ornamental climbers chiefly natives of Africa. Lin- 

 nffian class and order Octandria Monogynia, and 

 natural order Combretacece. Generic character : calyx 

 funnel formed and four lobed ; petals four, inserted 

 in the calyx ; so also are the stamens, and opposite 

 the petals ; anthers two celled, and burst longitudi- 

 nally ; style pointed ; fruit like a nut, containing one 

 seed, and winged ; seeds pendent. This beautiful 



fenus is of but late introduction into our collections, 

 n 1818 there were but two species, at present we 

 have at least thirteen. They all thrive well in the 

 compost usually made for stove plants, namely, loam 

 and moor-earth. All the species may be increased 

 by cuttings or layers. 



COMBUSTION, SPONTANEOUS. There 

 are many facts which lead to prove the existence of this 

 extraordinary natural process. In ordinary cases the 

 combustible substance is set on fire by its temperature 

 being artificially raised by friction, percussion, or the 

 application of some other burning body. Then heat 

 and light are evolved ; the body takes fire, and this 

 is what is termed combustion. It arises from the 

 particles of one substance entering into chemical 

 combination with the particles of another ; thus pit- 

 coal or fire-wood entering into combination with the 

 oxygen of the atmosphere yield a vast quantity of 

 light and heat ; and the more rapid the combination 

 is which takes place, the more vivid is the light, the 

 more intense the heat. Fkme, therefore, is the vola- 

 tilised matter of the combustible body entering rapidly 

 into combination with the oxygen or gas that supports 

 the combustion. In the case of a candle, the tallow 

 or wax is converted into vapour, which enters into 

 combination with the oxygen of the surrounding air, 



and becomes heated to whiteness. The flame is a 

 film of this hot white vapour, enclosing within it a 



Quantity of the same vapour, which, when the outer 

 1m is consumed, comes in contact with the oxygen, 

 and is in its turn consumed. Hereby the flaine is 

 sustained, and as the supply of vapour diminishes as 

 it ascends, the flame tapers to a point Several sub- 

 stances undergo combustion at a very low tempera- 

 ture. Phosphorus at the common temperature of the 

 air undergoes slow combustion ; it emits a white 

 vapour, is luminous in the dark, and is gradually con- 

 sumed. When combined with a certain quantity of 

 hydrogen it forms a gas, which is so highly inflam- 

 mable that it bursts into flame the moment it comes 

 into contact with the atmosphere. The illuminating 

 and heating qualities of the coal gas and oil gas are 

 well known ; they require, however, to be ignited 

 before combustion takes place. The sources of com- 

 bustion, or the circumstances which excite the com- 

 bustible body into a state of combustion, are numerous 

 and sometimes not easily determined. The cause of 

 subterranean fires and volcanoes has been referred to 

 the decomposition of pyrites or the metallic sulphurets 

 which exist below the surface of the earth. Indeed 

 the disengagement of heat is a constant result of 

 chemical action ; it is always evolved whenever a 

 substance without change of form passes from a rarer 

 into a denser state ; as when a gas becomes a liquid ; 

 or a liquid solidifies. In fermentation so considerable 

 a degree of heat is often evolved that visible combus- 

 tion ensues ; hence stacks of hay, turf, flax, hemp, 

 &c., when put up wet, frequently take fire. The light 

 and heat emitted during combustion vary with the 

 nature of the combustible substance ; the flame some- 

 times being white, yellow, blue, orange, or deep red ; 

 and the heat often very low, though the substance be 

 ultimately consumed. Several bodies seem to con- 

 tain light as a constituent, which in escaping renders 

 them luminous, as if surrounded by a lambent flame, 

 varying in colour according to the body whence it 

 arises. The minerals which possess this property are 

 called phosphorescent, as fluor spar, or phosphate of 

 lime. Many animal substances part with their con- 

 stituent light when they begin to putrefy ; thus 

 different kinds of meat and fish, as the haddock, 

 herring, mackerel, when putrefaction commences, 

 appear luminous in the dark. The source of the light 

 and heat given out during combustion is not well 

 understood ; many consider the phenomenon entirely 

 electrical. The combustibility of bodies, or their dis- 

 position to combine with a greater or less rapidity 

 with oxygen, or any other gas which supports 

 combustion, varies considerably. Many animal and 

 vegetable substances in decomposing give rise to a 

 combination between phosphorus and hydrogen, 

 which produces the gas above referred to, which 

 ignites immediately it comes in contact with the 

 atmosphere. This is the cause of the ignis fatuus or 

 will o' the wisp, which is charged with the sin of be- 

 traying weary travellers into bogs and quagmires. 

 The secret, however, is that such places abound with 

 animal and vegetable remains undergoing putrefaction. 

 The mysterious visitants have been detected rising in 

 the form of air-bubbles to the surface of the earth or 

 water, and suddenly taking light. Their flickering 

 motion too may be ascribed to the agitation of the 

 air by which they are surrounded ; so that these faery 

 torches are by the stern exorcism of science divested 



