IND 



IND 



gape). A term applied, in Botany, to 

 the state of those fruits in which the 

 pericarp, when arrived at maturity, con- 

 tinues perfectly closed, as in the hazel 

 nut. See Dehiscence. 



INDE'NTED. A term applied to any 

 part of a body which is depressed or sunk 

 beneath the surrounding surface, whether 

 the indentations consist of lines, dots, 

 irregular cavities, or tooth-like depres- 

 sions. 



INDEPENDENT COAL FORMA- 

 TION. By this term Werner designated 

 the first or oldest formation, because the 

 individual depositions of which it is com- 

 posed are independent of, and uncon- 

 nected with, one another. It contains 

 exclusively coarse coal, foliated coal, 

 c«nnel coal, slate coal, a kind of pitch 

 coal, and slaty glance coal. 



INDESTRUCTIBI'LITY. That pro- 

 perty of matter by virtue of which it 

 never ceases to exist : it may change its 

 form, and disappear ; but it is not anni- 

 hilated. In what is called destructive 

 distillation, the matters subjected to the 

 operation are evidently indestructible ; 

 for the products, when collected and 

 weighed, are found to be exactly as 

 heavy as the original matters. 



INDETE'RMINATE. 1. In Mathe- 

 matics, a problem is said to be inde- 

 terminate, when it admits of an infi- 

 nite number of solutions. 2. In Algebra, 

 the co-etficients of an assumed form of 

 expansion are said to be indeterminate, 

 and the process by which they are then 

 found, is called the "method of indeter- 

 minate co-efficients." 3. If one equation 

 contain two unknown quantities, the 

 number of values of these by which it 

 will be satisfied, is unlimited, and the 

 equation is said to be indeterminate. 



INDEX {indico, to point out). 1. In 

 Algebra, a small figure placed at the right 

 of a quantity, to signify its power (See 

 Exponent). 2. The index of a logarithm, 

 or its characteristic, is the 5gure prefixed 

 to the logarithm for the purpose of indi- 

 cating the unit's place in the correspond- 

 ing number. 3. In optics, the index of 

 refraction is the constant ratio which ex- 

 ists between the sines of the angles of 

 incidence and refraction. 



I'NDIANITE. A whitish or greyish 

 mineral, consisting of silica, alumina, 

 lime, iron, and manganese, occurring in 

 masses in the Carnatic, where it consti- 

 tutes the gangue of corundum. 



INDI'CATIVE MOOD {indico, to 

 point out). In Grammar, that condition 

 178 



of the verb which declares the action or 

 state to exist simply and as a fact. 



INDI'CTION. In Chronology, a re- 

 volution of fifteen years, as already no- 

 ticed under the term Era. Its origin 

 has not been ascertained ; but Gibbon 

 observes, that the name and use of the 

 "Indictions" were derived from the 

 Roman tributes. There are four descrip- 

 tions of Indictions :— 



1. The Indiction of Constantinople, 

 which was instituted by Constantine in 

 A. D. 312, and began on the 1st of Sep- 

 tember. 



2. The Imperial or Cesarean Indiction, 

 which began on the 24th of September. 



3. The Roman or Pontifical Indiction, 

 which commences on the 25th of Decem- 

 ber or 1st of January, according as either 

 of these days was considered as the first 

 of the year. This was generally used in 

 papal bulls, at least from the ninth to 

 the fourteenth century. 



4. The fourth kind of Indiction, which 

 is to be found in the register of the par- 

 liaments of Paris, began in the month of 

 October. 



INDI'FFERENCE. This term, in its 

 application in respect of the will and of 

 the judgment, is subject to an ambiguity 

 which may perhaps be thought hardly 

 worth noticing, the distinction between 

 unbiassed candour and impartiality on 

 the one side, and carelessness on the 

 other, being so very obvious. Yet, under 

 the same name, these things are con- 

 founded ; and, in fact, the judgment is 

 often, though by no means always, biassed 

 by the will. Our aim should be to pre- 

 serve the indiflference of the judgmentf 

 even where the will neither can nor should 

 be iwdXSexexvt. — Whately. 



INDI'GENOUS {indigena, a native). 

 A term applied to animals or plants pe- 

 culiar to a certain country. 



INDIGO. A blue pigment, obtained 

 from the leaves of all the species of 

 Indigofera, and various other plants. 

 White indigo, also called reduced indigo, 

 is procured by the action of deoxidizing 

 bodies upon blue indigo; in this state, 

 Liebig termed it indigogen. 



I'NDIGOLITE. An indigo-coloured 

 crystallized mineral, found at Utoe in 

 Sweden, and considered to be a variety 

 of tourmaline. 



INDIGO'TIC ACID. Anilic Acid. An 

 acid formed when indigo is dissolved in 

 nitric acid considerably diluted. This is 

 the nitranilic acid of Berzelius. 



INDIVI'DUAL {individuus, that can- 



