890 INDIGO 



In order to supply an establishment of tho common kind, where 100 eggs are to bo 

 hatched daily, a dozen of hons would be needed, and 150 eggs must bo placed under 

 them, as only two-thirds in general succeed. At this rate, 4,300 mothers would be 

 required to sit. Now supposing wo should collect ten times as many hens, or 43,000, 

 we should not be able to command the above number of chickens, as there is seldom a 

 tenth part of hens in a brooding state. Besides, there would be in this case no fower 

 than 720 hens every day coming out with a fresh brood of chickens, which would 

 require a regiment of superintendents. 



Artificial Incubation by means of Hot Mineral Waters. This curious process is 

 described very briefly in a letter by M. D'Arcet. The following are extracts from his 

 letter : 



' In June 1825, I obtained chickens and pigeons at Vichy, by artificial incubation, 

 effected through the means of the thermal waters of that place. In 1827 I went to the 

 baths of Chaudes-Aigues, principally for tho purpose of doing tho same thing there. 

 Finding the proprietor a zealous man, I succeeded in making a useful application of 

 this source of heat to the production of poultry. 



' The advantage of this process may be comprehended, when it is known that the 

 invalids who arrive at Vichy, for instance in the month of May, find chickens only the 

 size of quails ; whereas, by this means, they may be readily supplied six months old. 



' The good which may be done by establishing artificial incubation in places where 

 hot springs exist, is incalculable; it may be introduced into these establishments with- 

 out at all interfering with the medical treatment of patients, since the hatching would 

 go on in winter, at a time when the baths for other purposes are out of use. 



' There is no other trouble required in breeding chickens, by means of hot baths, 

 than to break the eggs at the proper time ; for, when the apartments are closed, the 

 whole of the interior will readily acquire a sufficiently elevated and very constant 

 temperature.' 



INDIA-RUBBER. See CAOUTCHOUC. 



INDIAN CORN. The Zea Mays. See "MAIZE. 



INDIAN FIRE. A pyrotechnic composition, sometimes used for signal-lights. 

 It is composed of 7 parts of sulphur, 2 of realgar, and 24 of nitre. 



INDIAN HEMP. A narcotic resinous substance obtained from Cannabis Indica. 

 See HEMP. 



INDIAN INK, or China Ink. A very beautiful black pigment, the best 

 varieties of which are obtained from China. It is composed of a very fine black, 

 cemented together with some kind of animal gelatine. See INK. 



INDIAN MATTING. Mats made in India from the reed Papyrus corymbosus. 



INDIAN MIIiliET. The Panicum miliaceum, a grain cultivated in the East 

 Indies. 



INDIAN RED. A mineral substance from the Persian Gulf, which reaches us in 

 a state of a dark red coarse powder: a silicate of iron and alumina, containing lime 

 and magnesia. The same name is given to a pigment artificially prepared, which 

 is essentially a sesquioxide of iron. 



INDIAN TEAK.. A hard wood used for ship-building, yielded by the Tcctona 

 grandis. 



INDIAN YELIiOW. This is a peculiar precipitate obtained from the urine of 

 the cow, and, according to some authorities, of the camel, after the animal has been 

 eating decayed and yellow mango leaves the Mangistana mangifcr. It appears to be 

 composed of magnesia with a yellow body which may be prepared pure by boiling the 

 mass with water, to which small quantities of muriatic acid are added, until the whole 

 dissolves, and then filtering. On cooling, the liquor deposits the colouring matter in 

 brilliant yellow scales, termed purreic acid. See Watts's ' Dictionary of Chemistry.' 



INDIANITE. An Indian variety of anorthite, or lime-felspar. 



INDICAN. A colourless substance existing in woad, and probably in other 

 plants yielding indigo. Indigo-blue may bo prepared from iudican by treating it with 

 sulphuric or hydrochloric acid. See INDIGO. 



INDICOIiITE. A name applied to the blue varieties of tourmaline. 



INDIGO. This invaluable dye-stuff consists essentially of a blue colouring matter, 

 to which the name of Indigo-blue has been applied. This colouring matter occurs in 

 the leaves of several species of plants, which, though few in number, belong to very 

 different genera and orders. The only native European plant which is known with 

 certainty to yield it is the Isatis tinctoria, or common woad. It has also been supposed 

 to occur in the following plants, all of which arc natives of Europe, viz. : Astragalus 

 glycyphyllos, Centaurea Cyanus, CJiclidonium majus, Cicer arictinum, Colutea arbo- 

 resccns, Coronilla Emerus, Galega officinalis, Hedysarum Onobrycliis, Inula Hclcniu?n, 

 Iris Germanica, Lotus corniculatus, Medicago sativa, Mercurialis perennis, Polygonum 

 aviculare, Polygonum Fagopyrum, JRhinanthus Crista-galli, Sambucus nigra, Sambvcua 



