EPF 



EL A 



2. Ecliptic, Plane of. A plane sup- 

 posed to pass through the ecliptic, and to 

 be indefinitely extended. In other words, 

 it is the plane which contains the earth's 

 orbit. 



3. Ecliptic Digit. The twelfth part of 

 the diameter of the sun or moon ; a term 

 employed for defining the magnitude of 

 an eclipse. Thus, an eclipse is said to be 

 of ten digits, if ten parts of the twelve 

 constituting the diameter are concealed. 



4. Ecliptic Limits. The greatest dis- 

 tances at which the moon can be from 

 her nodes, in order that an eclipse of the 

 sun or moon may take place. 



E'DDY (Sax. ed, water, ea, backwards). 

 A circular motion of the water, occurring 

 in rivers when the proper current meets 

 a counter current ; and in seas, where 

 two currents run in parallel, but diflferent, 

 directions, as between the equatorial and 

 the North African current. See Whirl- 

 pool. 



EDENTATA {edentulus, toothless). 

 An order of the Mammalia, agreeing in 

 the unimportant character of the absence 

 of incisive teeth. The order may be 

 distinguished into the edentata proper, 

 containing the ant-eaters, armadillos, &c., 

 all of which are insectivorous ; and the 

 tardigrada, or sloths, characterized by 

 the slowness of their motion. 



The term Edentata has also been ap- 

 plied to a group of Crustaceous animals, 

 in which the mouth is prolonged in the 

 shape of a sucker. See Maxillosa. 



E'DINGTONITE. A crystalline mine- 

 ral, found implanted upon crystallized 

 Thomsonite, in the Kilpatrick hills, near 

 Glasgow, accompanied by calcareous spar 

 and harmotone. 



EDRI'OPHTH A'LMA (^5paIop, sessile, 

 6(p$a\ij.oi, the eye). A group of the 

 malacostracous Crustacea, which have 

 immoveable sessile eyes. It comprises 

 the orders Amphipoda, Laemodipoda, and 

 Isopoda. See Podophthalma. 



EDULCORA'TION {dulcis, sweet). 

 The process of freeing a difficultly soluble 

 substance from one that is easily soluble 

 by means of distilled water. It differs 

 little from lixiviation, except that the 

 former term respects the insoluble re- 

 sidue, the latter the soluble portion. 



EDULCORA'TOR. Dropping Bottle. 

 An instrument for supplying small quan- 

 tities of water to test tubes, watch-glasses, 

 &c., by causing water to drop from a 

 phial, properly prepared, by expansion of 

 the liquid by the warmth of the hand. 



EFFERVE'SCENCE {effervesco, to 

 116 



grow hot). The commotion produced in 

 liquids by the rapid escape of gas, in the 

 form of bubbles, as on pouring acid on 

 chalk. 



EFFLORE'SCENCE (effloresco, to blow 

 as a flower). The pulverescence of crys- 

 tals, by the removal of their moisture, on 

 exposure to the air. See Deliquescence. 



E'GERAN. A sub-species of pyramidal 

 garnet, occurring in a bed of felspar and 

 hornblende, at Haslan, near Eger in Bo- 

 hemia. 



EIGHTH (in Music). The octave or 

 eighth note of the diatonic scale. It is a 

 perfect concord, and harmonizes with the 

 fifth and the third. It may form a part 

 of any chord. 



EI'SENRAHM. A term applied to 

 a red and a brown ore— the scaly iron 

 ore, and the scaly magnetic ore. 



ELA'IN (eKaiov, oil). The oily prin- 

 ciple of solid fats, so named by its dis- 

 coverer, Chevreul: this and stearins 

 constitute the fixed oils. Elaic or oleic 

 acid is obtained from elain by saponi- 

 fication with a strong solution of pot- 

 ash. 



ELA'OLITE {Uaiov, oil, X/^of, a 

 stone). A sub-species of pyramidal fel- 

 spar, of a blue and of a red colour. The 

 former is opalescent, and is termed fett- 

 stein by Werner, from its resinous nature. 



ELAIOMETER {^Xaiov, oil, /xerpoi/, a 

 measure). An instrument for detecting 

 the adulteration of olive oil. 



ELAO'PTEN {eXaiov, oil). The liquid 

 portion of a volatile oil. The concrete 

 portion is called stearopten. 



ELA'STIC CURVE. The figure as- 

 sumed by an elastic plate, of which one 

 end is fixed horizontally, while the other 

 end is loaded with a weight which, by its 

 gravity, produces the curve. 



ELASTI'CITY {hXavv(c, to push or 

 drive back). The property or power by 

 which a solid or fluid body, when com- 

 pressed or forcibly expanded, endeavours 

 to reassume its former bulk. 



E'LATER (eAaT»;p, a driver). A spiral 

 fibre, enclosed in a membranous case, 

 found in great numbers mixed with the 

 sporules, in the thecae of some crypto- 

 gamic plants. When fully ripe, the 

 membranous case usually disappears, the 

 spiral fibres, which are powerfully hygro- 

 metric, uncurl, and the sporules are dis- 

 persed. 



ELATE'RIDjE. a family of Coleo- 

 pterous insects, belonging to the section 

 Sternoxi, and named from the genus 

 Elater, a species of which (noctilucus) 



