Next after Euclid's Elements the Elements of ye Conic sections
are to be understood. And for this end you may read either the first part of
ye Elementa Curvarum of John De Witt, or De la Hire's
late treatise of ye conick sections, or Dr Barrow's epitome of
For Algebra read first Barthin's introduction & then peruse such
Problems as you will find scattered up & down in ye
Commentaries on Cartes's Geometry & other Alegraical writings of Francis
Schooten. I do not mean yt you should read over all those
Commentaries, but only ye solutions of such Problems as you will
here & there meet with. You may meet with De Witt's Elemenla
curvarum & Bartholin's introduction bound up together
wth Carte's Geometry & Schooten's commentaries.
For Astronomy read first ye short account of ye
Copernican System in the end of Gassendus's Astronomy & then so much of
Mercator's Astronomy as concerns ye same system & the new
discoveries made in the heavens by Telescopes in the Appendix.
These are sufficient for understanding my book: but if you can procure
Hugenius's Horologium oscillatorium, the perusal of that will
make you much more ready.
At ye first perusal of my Book it's enough if you understand
ye Propositions wth some of ye Demonstrations
wch are easier then the rest. For when you understand
ye easier they will afterwards give you light into ye
harder. When you have read ye first 60 pages, pass on to
ye 3d Book & when you see the design of that you may
turn back to such Propositions as you shall have a desire to know, or peruse
the whole in order if you think fit.