DESCENT. 
i other. Thus a ball of a — {wifter than wood 
cork, becaufe it lofes lefs o 
ae both fall with equal ti 
The caufe of this ae or 7 eaten downwards, has 
been greatly controverted. 
thefes advanced; the on eed n in- 
ternal, and the aes from an external pancle: ae “fil 
ia ae by the Pertparerics and Epicureans, and 
e Newrontans; and the latter 7. the CarTESIANS 
mee Cc ee ACCELERATIO 
Laws of the Descert of 3 Bodies ice avy bodie 
an unrelifting medium, fall with’ an panes) decccrred 
otion. See the Jaws of ae 3 accelerated motion, under 
the articles ACCELERATION and Morton. 2. The fpace 
defcribed by a body, urged by an uniform gra ee is fub- 
duple of that ack jit. would deferibe in the fame e by 
the velocity lait acquired and uniformly continue 
Galileo, who firt difcovered the Jaw of the defeent of heavy 
bodies by poeeuh — rds confirmed the fame by ex- 
periments, the refu lero epeated often ee by him 
i fince his time, - Grim ioli, Huygens, Ne 
many others, was, 3. That the fpaces of fee were as 
the {quares a saa iia or the fquares of the velocities. 
CCELE 
“Dr, Delagulicn | ane the effec of epee eae by 7 
ing a leaden ball to fall from the inner c f St. Pau 
ts weight, though in vacuo f 
feet, in the fir fecond - ue and paaaals the velocit, - 
time fis 32¢7, and that the fpace defcended is vy #7. 
et v denote the elit, and s the = corefponding 
to the time ¢, and put g = 16,4; then we fhall hav 
— 28 
vm2gim2 Vf/o9s= 
vy 
2S eF SS 279 
4S 
Vv S 28 
a 
25 g v 
See ACCELERATION 
The fpace deferibed by a defe-nding body ina fecond 
of tim = been alfo afcertained by experiments with 
endu ie In the latirude of London the lenath of a 
pen idee ‘vibrating feconds is 39% inches; and Gace the 
circumference of a circle is to its dances as the time of 
one vibration of a endulum is to the time in which a 
heavy body will fall ee balf the length of the pen- 
, which is 
1 
16” 
he time of defcending through 19,° inches, or half the 
la of the panies and, {paces being as the fquares of 
dulum, we fhall have 3.1416 : 1s: 1: 
church, whofe altitude from the oe is 272 feet the times, t I? :: 19% : 193 inches, or 16 feet 
Through a {pace the ball defended in ae feconds ; during 14.16 
which time it fhould, according to the theory, have defcend. 2 inch pwhich s the {pace Regia which a heavy body 
ed dheceat be eet, making a difference of abo e-fifth Will defcend in one fecond, as before. See PENDULUM. 
e of the ai 
= fi ail pene Mr. Atwood contrived his appara- , 
s, for an account of whi ch, fee Mor 
Gain aldi aaa Riccioli made eS oeineie to the fame ef- 
&, though in a different a by oe fall a number 
of ba lls, ere ight ounces a-piece, from the tops of 
feveral towers, and mea a uring the fag a falling by a pene 
dulum ve iol, Alm ib. ii. 
prop. 4. Thefe eae are fe exhibieed in the flguiie 
table. 
Vibrations Space at the Space 
of the Time end of the de{cended 
Pendulum. i each Time 
ne Rom. Foot. | Rom. Foot. 
5 o 50 Io 10 
10 I 40@ 40 30 
15 2 30 go 50 
20 3 20 160 70 
25 4 10 250 90 
6 Tt oO 15 15 
12 2 0 50 45 
18 3 0 135 15 
24 4 0 240 105 
By fuch and a saint ra a as defcended by 
a heavy body, in a given en afcertained ; 
and he ef e have been d nee nie ‘orem os for eftimating the 
times, velocities, and alfo the fpaces defcended, as - as 
they depend on an a aed of grav ee From 
accurate experiments ngland, been found 
that a heavy body ling frecly sceaas through 1624 
any saree of 164, for the value of g in the 
4 The time wherein a aa A falle from a given height 
m_ being a to determine the {paces it fell in the feveral parts. 
of that t 
uppo ate oe given ae = a, the time = 4, and the {pace 
it fell in one part of t then 
a 
[Toll 
e e ° 
Therefore the {pace paffed over in the firft part of time ie 
= confequently that paffed over in the feeond time = 3 
54 
that in the third = “ar ce See ACCELERATION, art. 3¢ 
5. The time wherein a epee oo eee a given {pace 
being given; to det the ee t will fal} 
through any ‘other pe ee in ihe fame 
Since the {paces are asthe {quare of the Gas, fe a the {pace 
quare of the given time, a 
the fquare of the time eta cou 
he fquare root, eet being extraéted therefrom, the 
gc is folve 
pace a body falls in a given time being give 
to determine obs {pace through which it will fall in any oni 
give 
To ie uae of the time wherein the body falls through 
ne given {pace, the fquare of the time wherein it fhould fall: 
rough the {pace required, and the given fpace, feel a fourth 
propttona this will be the fpace required. 
. For er conftant force, inftead o erpendi+ 
cular free ae by gravity, find the {pace defended. in one 
fecond by a body urged by that face and fubftitute that 
preceding formule :: 
r, if the proportion of this force to that of gravity be known, © 
let the value of g be altered in the fame Proportions _ the- 
