fcLA 



ELA 



Elaeaeni, Jussieu. Essential character : 

 corona, none ; calyx four-cleft, bell-form, 

 superior : drupe below the calyx. There 

 are nine species. 



ELJEIS, in botany, a genus of the Ap- 

 endix Palmae. Natural order of Palms. 

 Essential character : male, calyx six-leav- 

 ed ; corolla six-cleft ; stamens, six. Fe- 

 male, calyx six-leaved ; corolla six-petal- 

 led ; stigmas three ; drupe fibrous ; nut 

 one to three valved. There is but one 

 species, viz. E. guienensis. It is called 

 in the West Indies the oily palm. The 

 fruit of this tree was first carried from 

 Africa to America by the negroes. It 

 grows in great plenty on the coast of 

 Guinea, and also in the Cape de Verd 

 islands. 



From this fruit the inhabitants of the 

 West-India islands draw an oil, in the 

 same manner as it is extracted from 

 olives. They also extract a liquor from 

 the body of the tree, which when fer- 

 mented has a vinous quality, and will in- 

 ebriate. The leaves are wrought by the 

 negroes into mats, on which they re- 

 pose. 



EL^OCARPUS, in botany, a genus of 

 the Polyandria Monogynia class and or- 

 der. Natural order of Guttiferae, Jussieu. 

 Essential character : calyx five-leaved ; 

 corolla five-petalled, jagged ; anthers 

 two-valved at the tip ; drupe with a curl- 

 ed shell. There are six species, mostly 

 natives of the East Indies. 



ELJEODENDRUM, in botany, olive 

 wood, a genus of the Pentandria Monogy- 

 nia class and order. Essential character : 

 corolla five-petalled : drupe ovate, with a 

 two-celled nut. There are two species, 

 of which K. orientale is a moderate sized 

 twiggy shrub, or tree, a native of the 

 oriental regions : leaves ovate lanceolate, 

 smooth, slightly waved, sometimes in- 

 clining to a subserrated appearance on 

 the upper parts of the shoots; flowers 

 borne towards the ends of the branches, 

 of a pale green colour, supported on 

 shortish pedicles, each of which springs 

 from a longer common pedicle. 



ELASTICITY, that disposition in bo- 

 dies by which they endeavour to restore 

 themselves to the posture from whence 

 they were displaced by any external 

 force. The principal phenomena ob- 

 servable in elastic bodies are : 1. That an 

 i, elastic body (j. . a body perfectly elastic, 

 if any such there be) endeavours to restore 

 itself with the same force with which it 

 is pressed or bent. 2. An elastic body 

 exerts its force equally towards all sides, 

 though the effect is chiefly found on that 



side where the resistance is weakest, aS 

 is evident in the case of a gun exploding 

 a ball, a bow shooting out an arrow, &c. 

 3. Elastic bodies, in what manner soever 

 struck, or impelled, are inflected, and 

 rebound after the same manner : thus a 

 bell yields the same musical sound, in 

 what manner or on what side soever it 

 be struck ; the same of a tense or musical 

 chord; and a body rebounds from a 

 plane in the same angle in which it meets 

 or strikes it, making the angle of inci- 

 dence equal to the angle of reflection, 

 whether the intensity of the stroke be 

 greater or less. 4. A body perfectly fluid, 

 if any such there be, cannot be elastic, if 

 it be allowed that its parts cannot be 

 compressed. 5. A body perfectly solid, 

 if any such there be, cannot be elastic; 

 because, having no pores, it is incapable 

 of being compressed. 6. The elastic 

 properties of bodies seem to differ, ac- 

 cording to their greater or less density 

 or compactness, though not in an equal 

 degree : thus, metals are rendered more 

 compact and elastic by being hammered; 

 tempered steel is much more elastic than 

 soft steel ; and the density of the former 

 is to that of the latter as 7809 to 7738 : 

 cold condenses solid bodies, and renders 

 them more elastic ; whilst heat, that re- 

 laxes them, has the opposite effect : but, 

 on the contrary, air, and other elastic 

 fluids, are expanded by heat, and ren- 

 dered more elastic. 



Some philosophers account for elastici- 

 ty from the principles of corpuscular at- 

 traction and repulsion : thus, if a steel 

 spring, wire, or piece of very thin glasss, 

 be bent out of its natural position, the 

 particles on the convex part are forced 

 from the intimate union they had before ; 

 and, on the concave part, they are forced 

 nearer together, or harder upon each 

 other, than in the natural state : in both 

 which cases there will be a considerable 

 resistance to overcome, and consequently 

 require a superior force. During this 

 state of the particles, they may be said to 

 be under a sort of tension on one side, 

 and compression on the other : and since 

 by this force they are not drawn out of 

 each other's attraction, as soon as the 

 force is remitted, or ceases to act, the at- 

 tractive power reduces the particles, and 

 unbends the wire. Now it is well known, 

 that many substances are composed of 

 such fibrous parts or filaments which re- 

 semble fine wires, and are interwoven; 

 and disposed in such a manner, as in 

 sponge, for instance, that they cannot be 

 compressed without being bent or wrest- 



