M O T 
orbit being fo much greater than the ordinary, or even 
extraordinary, forces applied to move bodies in any novel 
direction, the phenomenon called by the name of gravi¬ 
tation is a neceffary refult of a preponderating coincident 
motion in another direction, all contrary or foreign motions 
being ultimately deftroyed by the refilling medium of the 
atmofphere and the defledlive circular motion. 
The weight of bodies, then, adls on the fame principle 
as their momentum in the orbit of the earth, becaufe 
every force which exhibits the phenomena of weight 
affedls the paramount orbicular force; and, this aflive 
principle is, therefore, merely a phenomenon refulting from 
the orbicular momentum, regulated ly the rotary motion, 
which rotary motion caufes all bodies to perform circuits 
inverfely as their quantities of matter, and which circuits 
are proportioned to the dillance from the centre. 
The phenomena of weight and gravitation, and of fall¬ 
ing bodies, may therefore be confidered as a relult of the 
compcfition of forces produced by the annual and diurnal 
motions of the earth and its adjundts. Ol courfe, all the 
motions and laws of projedtiles are lubordinate to the-le, 
and are included within them. 
On a fmall fcale, the principle may be illuftrated by 
experiments of analogous phenomena, in which it will 
appear that any lateral motion of bodies produces the 
fame refults as the earth itfelf; and that, as a conlequence 
of every fuch lateral motion, the projedtiles from fitch 
bodies refpedt, in falling, the bodies, whence they are pro- 
jedted, though no fufpicion or allegation of attradlion can, 
in fuch cafes, be adduced. 
Thus, as it is well known, a ball projedled from a fltip 
in motion falls at the place whence it role, though, during 
its afeent and defeent, the fltip proceeded many yards. 
The ball, though detached from the fltip, refpedled the 
fhip, during its flight and fall, exadtly as though it had 
been attrafted by the fltip. It cannot, however, be con¬ 
tended that fuch phenomena are refults of the fhip’s at¬ 
tradlion. The effedl arifes merely from the fhip’s lateral 
motion, having been acquired by the ball previoufly to 
its projedlion ; the cafe being exadlly the fame as that of 
a ball projedled above the earth, to which it falls again, 
on the very principle on which it fell on the fltip, not by 
the attradlion either of the fhip or the earth, but becaufe 
the earth’s lateral motion, like the lateral motion of the 
fhip, had been acquired by the ball. 
So, alfo, when a man, during feats of liorfemanfhip, 
throws up oranges in his courfe, he readily catches them 
again, though during their flight he advanced many yards, 
becaufe his lateral motion had previoufly been given to 
the oranges ; and in confequence, in falling again, they 
refpedled him juft as though, according to pre-exifting 
notions about the earth, he had attradled them. 
In like manner, if a ball be dropped from the top of 
the maft of a fhip, which at the time was moving at any 
given rate, the ball will fall perpendicularly at the foot 
of the mail, exadlly as though the fhip had been Handing 
flill; and will thus appear to be influenced by the fhip, 
and not by the earth, exadlly as a ball let to fall from a 
tower falls to the earth, and appears to refpedt the earth. 
In both cafes, the phenomena are regular and neceffary 
confequences of the compofition of motion, and there is 
no unfeen or occult power, called attradlion, concerned 
in one cafe more than in the other. 
Illujlration .—If a ball be projedled from A, fig. 3. per¬ 
pendicularly towards D, and A be fuppofed to be on the 
deck of a fhip, which is moving at any given rate, from 
the part A towards the part B ; then the ball, inftead of 
afeending to the point of fpace at D, will, without ma¬ 
terial error, move in the diagonal A C, by the com¬ 
pound forces which, in the fame time, would have carried 
it to D or F ; and in defeending it will fall to the deck 
at B, to which the point A, in the interim, has advanced. 
It has in truth performed, inftead of an apparent perpen¬ 
dicular, the two fides of the triangle, or the curve A C B ; 
end, inftead of falling at the point of fpace A, whence it 
ION. Ill 
was projedled, it has advanced with the fhip, and fallen 
at the point of fpace B, to which A has advanced ; and 
in falling has refpedled the fhip, and not the point of 
fpace, or the earth at A. It was not however attradled 
by the fhip, but merely impelled in the diagonal by the 
motion of the fhip, in which it previoufly participated. 
Thefe cafes fully illuftrate the principle for which I 
contend ; but, of courfe, the relations and powers of the 
fhip, and man moving on the moving earth, are included 
within the more extenfive relations and powers operating 
in nature, in the prodigious forces generated by the 
annual and diurnal motions of our planet. The cafe of 
a body thrown upwards from a fltip in motion, merely 
fhows that, in falling, it obeys a law growing out of the 
motion of the fltip; in like manner as bodies projedled 
from the earth, or falling towards it, obey a fimilar law 
of motion growing out of fimilar motions of the earth. 
The law in both cafes is a mere refult of the compofition of 
motion, and not an effedl of any occult or mylterious 
power. 
Thefe examples, and others that might be adduced, 
ferve, however, to prove the exadt analogy of the powers, 
the phenomena, and the refults. No experiments in phy- 
fical philofophy feem to afford more conclufive analogi¬ 
cal proofs of dodlrines relative to any natural operations, 
which are too vaft to be viewed by man on their great 
fcale. 
The recognition of the principles of this paper may be 
expected to lead to more preciflon in the dodlrines of 
projedliles. Many incomprehenfible irregularities in Dr. 
Hutton’s and Mr. Robins’s experiments on gunnery may 
be found to arife from the contrariety, oppofition, or neu¬ 
trality, of the diredtion of the rotary motion, in relation 
to that of the orbicular motion. It will likewife be 
found that periodical fludluations in the weight and 
defledtions of the atmofphere and other fluids, may be 
traced to periodical variations in the relative diredlions 
of the mechanical forces, as in the tides, monfoons, trade- 
winds, See. 
To extend thefe principles to the folution of the phe¬ 
nomena of nature, and to deduce from them all the refults 
of which they are lufceptible, would be, in regard at leaft 
to nomenclature, to remodel the Principia of Newton, 
and to arrange a new fyftem of phyfics. Neverthelefs, 
I feel it proper to Hate, that thefe demonftrations of the 
true and neceffary caufes of the phenomena hitherto 
aferibed to an unknown power, called by the name of 
gravitation, merely fill fome important connedting terms 
in the feries of mechanical caufes afeertained by modern 
philofophy ; while they difturb none of the known rela¬ 
tions of bodies, as determined by experiment and obferva- 
tion, or by the geometrical and analytical inveftigations 
of Galileo, Kepler, Defcartes, Newton, Euler, La Grange, 
Herfchel; or La Place. 
A fummary of thefe dodlrines may, perhaps, without 
material error or omiffion, be expreffed in the following 
paragraphs: 
1. That bodies moved in the annual orbit of any planet 
acquire a momentum in the diredlion of the increments 
of that orbit fuperior to the influence of any other per¬ 
manent force which is communicated to them. 
2. That all variations in the diredlion of this orbicular 
motion are eftedted by defledtions of that paramount mo¬ 
tion, either by the rotary diurnal motion, or by fome 
mufcular, mechanical, or chemical, force. 
3. That the refiftance which bodies exhibit in being 
lifted, or thrown, or in any way turned, into any new 
diredlion, is the meafure of their weight, which is as their 
quantity of matter, becaufe it arifes from a velocity com¬ 
mon to the terreftrial fyftem in the diredlion of the orbit. 
4. That the phenomena of falling bodies are produced 
by the deftedtion of the circular rotary motion from the 
comparatively ftraight line of the orbicular motion. 
5. That every body, which has had any new diredlion 
of force given to it, is nevertheiefs lubjedt to .the perma- 
