Of Newton's Principia

                                proposed to the Contemplation of Naturall philosophers, whether 
the surprizing phenomena of the Elasticity of the air and some 
other fluids may not arise from their being composed of particles 
which flie each other, which being rather a physicall than 
Mathematicall Inquirie our Author forbears to discuss.
Next the Opposition of the Medium and its effects on the Vibra 
tions of the pendulum is considered, which is followed by an inqu 
iry into the rules of the opposition to bodies, as their bulk, shape 
or density may be varied <s>where among other things the motion 
of water running through a hole in a vessel is determined <\s>
here with great exactness is an account given of severall Ex
periments tried with pendula in order to verifie the afore 
going speculation, and to determine the quantitie of the 
Airs opposition to bodies moving in it.
From thence is proceeded to the undulation of fluids, the 
laws wherof are here laid down, and by them the <s>phenomena <\s> motion &
propagation of light and sounds are explained. The Last section 
of this book is concerning the circular motion of fluids 
wherin the nature of <u>their Verticall Motions is considered 
and from thence the Cartesian doctrine of<\u> the Vortices 
of the Celestiall matter carring with them the Planets about 
the Sun is proved altogether impossible.
The IIId and last book is entituled de Systemate Mundi, wherin 
the demonstrations of the two former books are applyed to the 
explication of the ..l phenomena of nature: Here the 
verity of the Hypothesis of Kepler is demonstrated; and a full 
solution given to all the difficulties  that occurr in the Astro