ANG 



ANI 



with the meridian at the pole of the 

 ecliptic. 



16. Angle, Horary. The angle formed 

 with the meridian of any place by a great 

 circle, which passes through a star and 

 the pole. 



17. Angle of Commutation. The angle 

 at the sun, formed by two lines, one 

 drawn from the earth, and the other 

 from the place of the plai.et reduced to 

 the ecliptic, meeting in the sun's centre. 



18. Angle of Elongation. The angle 

 formed by two lines drawn from the 

 earth, the one to the sun, and the other 

 to the planet ; or it is the difference be- 

 tween the sun's place and the geocentric 

 place of the placet. 



19. Angle of Evection. An inequality 

 in the motion of the moon, by which, 

 at or near her quadratures, she is not 

 in the line drawn through the centres 

 of the earth and sun, as she is at the 

 syzygies, but makes an angle with that 

 line of about 2° 51'. 



IV. In Mechanics. 



20. Angle of Draught. A term applied 

 to express that direction of a drawing 

 power which is best adapted to overcome 

 friction and weight ; and this is found to 

 be the angle made by the line of direc- 

 tion with a line upon the plane '5ver 

 which the body is drawn, and perpendi- 

 cular to that line of direction 



21. Angle of Direction and of Elevation. 



1. In mechanics, the angle of direction 

 is that comprehended between the lines 

 of direction of two conspiring forces. 



2. The angle of elevation is that which is 

 comprehended between the line of direc- 

 tion and any plane upon which the pro- 

 jection is made, whether horizontal or 

 oblique. 



22. Angle of Incidence and of Reflection. 

 When an elastic body strikes an elastic 

 plane at a certain angle, this body re- 

 turns under the same angle, but in the 

 opposite direction ; the former is called 

 the angle of incidence, the latter the 

 angle of reflection. 



V. In Zoology. 



23. Angle, Facial. An angle com- 

 posed of two lines, one drawn in the 

 direction of the basis of the skull, from 

 the ear to the roots of the upper incisor 

 teeth, and ,the other from the latter point 

 to the most projecting part of the fore- 

 head. 



24. Angle, Frontal. In Ornithology, the 

 angle which the culmen, or upper part of 

 the beak, makes with the forehead. 



27 



VI. In Fortification. 



25. Angles in Fortification. These are 

 of two sorts, real and imaginary. 1. Real 

 angles are those n hich actually exist and 

 appear in the wori.b, as the flanked angle, 

 the angle of the epaule, the angle of the 

 flank, and the re-entering angle of the 

 counterscarp. 2. Imaginary or occult 

 angles are those which are only subser- 

 vient to the construction, and which ex- 

 ist no longer after the fortification is 

 drawn, as the angle of the centre, the 

 angle of the polygon, the flanking angle, 

 the salient angle of the counterscarp, &c. 



ANGUl'NID^ {anguis, a snake). 

 Slow-worms ; a family of Ophidian rep- 

 tiles, which combine the characters of 

 the serpents and the lizards. They ap- 

 proach the latter in the possession of 

 rudimentary legs under the skin, as well 

 as in other points of their organization. 

 The slow-worm of this country, erro- 

 neously called blind worm, has remark- 

 ably brilliant eyes. 



A'NGULAR MOTION. The varia- 

 tion in the angle described by a line, or 

 radius, which connects a moving body 

 with the centre about which it moves. 

 Thus, a pendulum has an angular motion 

 about its point of suspension, and the 

 planets have an angular motion about the 

 sun. 



Angular Intervals, in Astronomy, mea- 

 sured liy means of the transit instrument 

 and clock, are those arcs of the equinoc- 

 tial, which are intercepted between cir- 

 cles of declination passing through the 

 objects observed. 



A'NHYDRITE (a, priv., vbiap, water). 

 Sulphate of lime ; a mineral occurring in 

 a crystalline form without water. 



A'NHYDROUS (a, priv., v6u>p, water). 

 Without water ; a term applied to crys- 

 tals and gases which are deprived of 

 water. See Hydrate. 



A'NILIC ACID. An acid formed by 

 the action of nitric acid upon indigo, and 

 named from the anil, a plant growing in 

 America, from the leaves of which indigo 

 is prepared. The acid was formerly 

 called indiflotic. 



A'NILINE. An oily liquid, which 

 distils over when finely-pulverized indigo 

 is decomposed by a highly concentrated 

 solution of caustic potash or soda, in a 

 retort. 



A'NIMA. The name given by Stahl 

 to the intelligent agent supposed to pre- 

 side over many parts of the animal eco- 

 nomy. This is the archceus of Van Hel- 

 mont, and has been termed the vital 

 C2 



