Letter

 1 XII|        in express terms, the new attraction, the invention of which
 2 XIV|        Isaac Newton, it is by an attraction, the cause of which is as
 3 XIV|          and subtile matter; but attraction prevails even in chemistry
 4 XV |                    Letter XV: On Attraction~The discoveries which gained
 5 XV | necessary to prove the system of attraction.~The instant we know the
 6 XV |          therefore, the power of attraction causes all the planets to
 7 XV |       very simple effect of this attraction. The proximity of the moon,
 8 XV |          power of gravitation or attraction acts on all the celestial
 9 XV |         on in infinitum.~This is attraction, the great spring by which
10 XV |  understood, rather than that of attraction, which is unintelligible?"~
11 XV |          impulsion as of that of attraction; and in case you cannot
12 XV |          Thirdly, I use the word attraction for no other reason but
13 XV |      existence was never proved. Attraction, on the contrary, is a real