( 211 ) 
Tho’ Sir Ifaac Newton , in his Trincipia , has not 
endeavour’d to give the Caufe of Gravity, or to deter- 
mine whether it be owing to an Impulfe or not j yet he 
has {hewn, what its Effe&s and Laws are, from plain 
Experiments made by others and himfelf. From the 
Laws of Gravity, and from the Ob fer vat ion of a Comet, 
* he has deduced the Annual Motion of the Earth ; and 
it muft have a Diurnal Motion, if it has an Annual one, 
other wife, it will not agree with the Than omen a. The 
Laws of the Centrifugal Force, or that Force by which 
a Body, whirl’d round in any Circle, endeavours to re- 
cede from the Center of its Motion, have been demon- 
flrated by Monf. Huygens. 
Thefe are the Principles from which Sir Ifaac New- 
ton draws his Concluhon ^ and tho’ fome Perfons, that 
will not be at the Pains to examine them, may deny 
them by the Lump, yet no Body has yet been able to 
(hew any Flaw in the Demonftrations that relate to 
them. 
NB. This ‘Differ tat ion will be continued in our 
next. 
* Princip. Lib. 3. Prop, iz, m, <Sc 42. 
1 > r • . > 
\ 
II. Some 
