APP 



APP 



protasis, which is the hypothetical or 

 limiting clause of a period. 



A'POGEE (ttTTo, from, 7^, the earth). 

 That point of the moon's orbit in which 

 she is furthest from the earth. Her 

 perigee is that in which she is nearest to 

 the earth. Formerly, when the earth 

 was considered as the centre of the sys- 

 tem, the terms apogee and perigee were 

 applicable to the places of all the planets, 

 and also of the sun, with respect to their 

 variable distances from the earth ; but 

 now they refer only to the moon. What 

 was then called the sun's apogee is now 

 the earth's aphelion ; and the perigee of 

 the former has become the perihelion of 

 the latter. 



APOPHY'LLITE (i7^o0l;X^/r«, to 

 strip off leaves). Ichthyophthalmile, or 

 fish-eije stone. A scarce mineral, having 

 a pearly lustre, like the species of felspar 

 called moonstone. It is found in the 

 iron mines of Uto, in Sudermania, a 

 province of Sweden. The term is derived 

 from the lamellar structure of the mine- 

 ral, and its exfoliation under the blow- 

 pipe. 



APO'PHYSIS Ox-nh, from, 0ua), to 

 grow). A process of a bone, and a part 

 of the same bone. An unequal expan- 

 sion sometimes found at the base of the 

 theca in mosses. 



A'POSIOPE'SIS (uTroo-itoTrdco, to be 

 silent after speaking). Literally, the 

 becoming silent; a rhetorical figure, by 

 which, for emphasis or modesty, the 

 sentence is broken off, as in Virgil, JEn. 

 I. 135. The aposiopesis is expressed, in 

 writing, by a short horizontal line at the 

 point where the sense is broken off. 



APOSTASIA'CE^. An order of Di- 

 cotyledonous plants, named from the 

 genus Aposlada, and closely allied to the 

 Orchidaceas, from which they differ essen- 

 tially in having a 3-celled fruit, with 

 loculicidal dehiscence, and in the style 

 being altogether free from the stamens 

 for the principal part of its length. 



APOTHE'CIA (uTTo, from, OnKt], a cap- 

 sule). Scutella, or little shields ; a term 

 applied, in Botany, to the reproductive 

 organs of lichens. 



APPA'RENT {appareo, to appear). A 

 term applied in Astronomy to those phe- 

 nomena which are actually observed, as 

 distinguished from real or true pheno- 

 mena, which result from correction or 

 reduction. Thus, the apparent altitude 

 of a star requires a correction for refrac- 

 tion; the apparent place of a planet 

 requires a reduction to that place in 

 34 



which it would be seen from the centre 

 of the earth. 



1 . Apparent diameter of a planet. The 

 angle made by two lines drawn to the 

 eye from the opposite points of the planet's 

 disk. The true diameter is the line which 

 joins the opposite points of the disk 

 itself. 



2. Apparent horizon. The sensible 

 horizon, or the plane in which lies the 

 circle which actually bounds our view. 

 The real or rational horizon is a plane 

 parallel to the preceding, drawn through 

 the centre of the earth. 



3. Apparent magnitude. The angle 

 under which any line appears at the eye ; 

 that is, the angle made by lines drawn 

 from its extremities to the eye. 



4. Apparent motion. The velocity and 

 direction in v/hich a body appears to 

 move, when the spectator is himself un- 

 consciously in motion. 



APPENDI'CULATE {appendicular a 

 little afipendage). That which has small 

 appendages, as applied in botany to the 

 calyx of Scutellaria. 



APPE'NDIX {appendo, to hang to). 

 An appendage; a process appended to 

 any part of a body, without being essen- 

 tial to the existence of the body, as a 

 thorn or gland in plants. 



A'PPETENCY (appeto, to seek). The 

 disposition of organized beings to acquire 

 and appropriate substances adapted to 

 their support. 



APPOSITION {appono, to place near). 

 That part of the function of nutrition, 

 by which the constituents of the blood 

 are transformed on the free surface of an 

 organ into a solid unorganized substance, 

 which is the mode of growth of the non- 

 vascular tissues. See Transformations. 



APPREHE'NSION, SIMPLE. In lo- 

 gic, that act or condition of the mind, in 

 which it receives a notion of any object. 

 It is analogous to the perception of the 

 senses. Incomplex apprehension regards 

 one object, or several without any rela- 

 tion being perceived between them, as a 

 man, a card, &c Complex apprehension 

 regards several objects with such a rela- 

 tion, as a man on horseback, a pack of 

 cards, &c. 



APPROXIMA'TION {ad, to, proxi- 

 mus, nearest). A result in experimental 

 philosophy, which approaches more or 

 less near to the truth, as the calculation 

 of the distance, or of the diameter, of a 

 celestial body. In mathematics, quan- 

 tities are said to be approximate, which 

 are nearly, but not absolutely, equal. 



^/:. 



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