E L A 
E L A 
E L E 
bodies are elastic or not, the snm of the mo- 
tions in the same direction, and the difference 
of the motions in a contrary direction, are the 
same both before and after collision. 
If two equal elastic bodies move towards 
each other with equal velocities, they will re- 
cede from each other after collision each with 
the same velocity. If one of them in motion 
(strikes against the other at rest, it will com- 
municate the whole velocity, and remain 
[ at rest itself. . If one overtakes the other, 
they will interchange velocities, and Continue 
: to go on the same way as before. If they 
meet eacli other with different velocities, 
f they will interchange velocities, and fly off 
from each other in contrary directions. 
If an elastic body strikes upon an immove- 
| able elastic obstacle, it will rebound with 
the same velocity that it came. 
If one of the impinging bodies is hard, 
j and the other elastic, the laws of thecommuni- 
[ cation of motion are the same as if both the 
bodies were elastic ; for the spring wdl give 
way, till the force of elasticity becomes equal 
1 to the force of compression, that is, double 
to the quantity of the stroke in each body ; 
| and the re-action of a hard body against dou- 
ble the quantity of elasticity, will produce 
the same effect as a single quantity of 
elasticity in each body, acting in contrary 
directions. 
If the impulse be oblique, it must be re- 
! solved into two impulses, one direct, and the 
i other parallel to the tangent at the point of 
j collision. The effect of the direct impulse 
must be computed according to the laws be- 
j fore mentioned : the parallel impulse will con- 
; tinue after the collision the same in all re- 
spects that it was before ; nor will it produce 
| any other effect, except by means of the 
friction to make the bodies revolve each 
j about its own centre of gravity. 
It often happens that the communication 
’’ of motion is the indispensable means of obtain- 
| ing some other effect ; thus it is used to nail 
and flatten bodies ; in these cases it is notsuffi- 
| dent, that the striking body has a certain quan- 
tity of motion, the mass or quantity of mat- 
: ter must be so proportioned with the velocity, 
I as to produce the required effect, without 
j splitting or destroying the body struck. 
In architecture there are many occasions, 
| where it is necessary to drive piles ; if the 
i mass which strikes the pile is small, it will not 
have force sufficient to drive it and if it is 
moved with considerable velocity, it will split 
| the head ot'the pile ; a large mass must there- 
fore be used, moving with less velocity. If 
| small hammers and a great velocity are used 
to drive pivots of iron into large pieces of 
wood, the head of the pivot will yield, and 
yet not be driven into the wood ; whereas 
the effect will be answered by using ham- 
mers of considerable weight, moving with less 
velocity. 
Gold-beaters and other workmen who 
flatten metals, make use of heavy hammers, 
and move them slowly; if they used small 
hammers, and moved them swiftly, the parts 
of the metal would be broken and divided by 
the strokes. 
To prevent the propagation of motion, 
and to deaden the blow, those that work in 
their chambers, and are obliged to use anvils, 
place the blocks that hold the anvil upon a 
roll of matting, or upon springs ; without 
this precaution, great part of the force im- 
pressed by the hammer would be transmitted 
to the floor, and would create a shaking to 
the prejudice of the building. 
The principles above laid down will assist 
in explaining the recoil of cannon, fu- 
sees, and other arms ; for you may con- 
sider the gunpowder as a spring which un- 
bends or expands itself in every direction, but 
which can only act efficaciously against the 
breech of the cannon and the ball. 
The action of the powder is that of two 
equal forces against two unequal powers of re- 
sistance, the ball and the cannon ; it may 
therefore be supposed, c&teris paribus, to 
impress them both with an equal quantity of 
motion, but with different degrees of velocity ; 
that of the ball being as much greater as its 
mass is less than that of the cannon, &c. 
The camion, the musket, &c. especially 
if you take into the account the obstacles 
which retain them, are much more difficult 
to mow than the ball with which they are 
charged; which, of course, receives from the 
inflamed powder a much greater degree of 
velocity. 
There are other circumstances which con- 
tribute to augment the velocity of the ball, 
as the length of the piece, kc. which do not 
come properly before us. As to the recoil in 
general, supposing the quantity and quality 
of the powder the same, a gun recoils so 
much the more as the bullet makes more 
resistance either by its weight or the wadding. 
A rocket flies upwards, because its lower 
part, which is fired, performs the office of a 
spring, which acts one way against the body 
of the rocket, and the other way against a 
volume of air; and as this spring is conti- 
nually renewed by the successive inflamma- 
tion of all the parts of the rocket, its motion 
is accelerated, first, because it is contained 
in the body itself, and is therefore continually 
adding to its velocity ; and secondly, because 
the weight or resistance of the rocket is dimi- 
nishing every instant by the dissipation of the 
parts as they burn away. 
ELATE, a genus belonging to the natural 
order of palms . There is no male calyx ; the 
corolla is tripetalous, with three stamina. 
There is no female calyx ; the corolla is tri- 
petalous, with one pistil ; the fruit is an oval 
acuminated plum. There is one species, a 
native of the East Indies, which grows to the 
height of 14 feet. The natives chew the nut 
in the same manner as the areca or the leaf of 
the betel. 
ELATEB, in zoology', a genus of insects, 
belonging to the order of coleoptera. The an- 
tennae are setaceous; and an elastic spring 
or spine projects from the hinder extremity 
of the breast or under side of the thorax. By 
means of this kind of spring, the animal, when 
turned upon its back, contrives to leap up 
into the air, and so turn itself. It varies in 
size; and when the insect is young arid newly 
metamorphosed, its elytra are of a beautiful 
deep red ; but in a few days they change to 
a much darker hue, and arenearly of a chesnut 
colour. In the state of larvse it inhabits the 
trunks of decayed trees, and is there trans- 
formed. With the help of its wings it issues 
from its prison, flutters upon flowers,' wanders 
over the fields, and conceals itself in thickets 
or under the bark of trees. There are 38 spe- 
cies. 
591 ; 
ELATERIUM, a genus of the monan- 
dria order, in the moncecia class of plants 
and in the natural method ranking under the 
34th order, cucurbitaceie. There is no male 
calyx ; the corolla is salver-shaped ; there is 
noffemale calyx ; the corolla is salver-shaped ; 
the capsule inferior, unilocular, and bivalved. 
There are two species, natives of America. 
ELATINE, a genus of the tetragynia or- 
der, in the octandria class of plants ; and in 
the natural method ranking under the loth, 
order, inundate. The calyx is tetraphyllous ; 
the petals four ; the capsule quadnloculaiy 
quadrivalved, and depressed. There are 
two species, annual aquatics of Europe. 
ELCESAITES, in church-history, a sect 
who made their appearance in the reign of 
the emperor Trajan, and took their name 
from their leader Elcesai. The Elcesaites 
kept a mean between the Jews, Christian®, 
and Pagans; they worshipped but one God, 
observed the Jewish sabbath, circumcision* 
and the other ceremonies of the law. They, 
rejected the Pentateuch and the Prophets'; 
nor had they more respect for the writings of 
the apostles, particularly those of St. Paul. 
ELECTION, is where a person has by. 
law two remedies, and is compelled to de- 
clare which he will abide by : thus a creditor, 
in cases of bankruptcy, may either prove his 
debt under the commission, or .proceed at 
law ; but in this case he is compelled to 
make his election. Where also a person 
having obtained a judgment, and is entitled 
to execution, he may either take his remedy 
against the goods or the person, and he mav 
choose either ; but if lie proceed against the 
person in the first instance, lie cannot after- 
wards have recourse to the goods; but if lie, 
takes the goods, and these should be found 
inadequate to his demand, he may afterwards- 
take the body. 
Election of bishops. See Bishops. 
Election of a cleric of statutes- 
merchant, a writ that lies for the choice of 
a clerk assigned to take and make bonds, 
called statutes-merchant, and is granted out 
ot'the chancery upon suggestion made, that 
the clerk formerly assigned is gone to dwell 
in another place, or is hindered from follow- 
ing that business, or has not land sufficient to. 
answer his transgression if he should deal, 
amiss. F. N. B. 164. 
Election of ecclesiastical per- 
sons. If any person that lias a voice in- 
elections, takes any reward for an election 
in any church, college, school, kc. such elec- 
tion shall be void; and if any such societies- 
resign their places to others for reward, they, 
incur a forfeiture of. double the sum ; and the 
party giving, and the party taking it, are 
thereby rendered incapable of such place., 
31 Eliz. c. 6. See Bishops. 
Election of members of parlia- 
ment. Qualification of the candidates. No 
member shall sit or vote in either house of 
parliament unless he be 2.1 years of age.. 4. 
Inst. 47. 
They must not be aliens-bovn ; they must 
not be any of the twelve judges, because they 
sit in the lords’ house. But persons who have 
judicial places in the other courts, ecclesias-- 
tical or civil, are eligible. 4 lust. 47.. Nor. 
of the clergy ; the reason assigned for which 1 
is, that they might sit in the convocation,. 
Nor persons attainted of treason or felony, , 
for they are unfit to sit any where. Id.. 
