my third book, it is all found among the celestial motions, not indeed
in the manner which I imagined (that is not the least part of my
delight), but in another very different, and yet most perfect and
excellent. It is now eighteen months since I got the first glimpse of
light, three months since the dawn, very few days since the unveiled
sun, most admirable to gaze on, burst out upon me. Nothing holds me; I
will indulge in my sacred fury; I will triumph over mankind by the
honest confession that I have stolen the golden vases of the Egyptians
to build up a tabernacle for my God far away from the confines of Egypt.
If you forgive me, I rejoice, if you are angry, I can bear it; the die
is cast, the book is written; to be read either now or by posterity, I
care not which; it may well wait a century for a reader, as God has
waited six thousand years for an observer." He gives the date 15th May,
1618, for the completion of his discovery. In his "Epitome of the
Copernican Astronomy," he gives his own idea as to the reason for this
Third Law. "Four causes concur for lengthening the periodic time. First,
the length of the path; secondly, the weight or quantity of matter to be
carried; thirdly, the degree of strength of the moving virtue; fourthly,
the bulk or space into which is spread out the matter to be moved. The
orbital paths of the planets are in the simple ratio of the distances;
the weights or quantities of matter in different planets are in the
subduplicate ratio of the same distances, as has been already proved; so
that with every increase of distance a planet has more matter and
therefore is moved more slowly, and accumulates more time in its
revolution, requiring already, as it did, more time by reason of the
length of the way. The third and fourth causes compensate each other in
a comparison of different planets; the simple and subduplicate
proportion compound the sesquiplicate proportion, which therefore is the
ratio of the periodic times." The only part of this "explanation" that
is true is that the paths are in the simple ratio of the distances, the