announced to an astonished public. Some of the discoveries, such as those relating to Saturn and Venus, were of such an astonishing and revolutionary nature that Galileo first published them in the form of anagrams. The one announcing the phases of Venus, when deciphered, reads as follows: "Cynthiæ Figuras Æmulatur Mater Amonun." Freely translated: "Venus emulates the phases of the moon." The immediate result of Galileo's brilliant work was to convince all unbiased minds of the truth and to array the church in solid phalanx against both him and his system. Of Galileo personally we have not time to speak—suffice it to say that he was made to suffer most cruelly for his beliefs.
In the year he died (1642) was born—on Christmas Day—the man
who was destined to establish forever the truths for which so many had toiled and suffered before him.
We have tried to follow one of the lines of succession leading up to Newton, giving, as it were, his pedigree upon the side of astronomy. It is a noble line: Pythagoras, Eratosthenes, Hipparchus, Ptolemy, Copernicus, Brahé, Kepler, Galileo, with many lesser names unmentioned. There is another line of succession to be traced, and to this I invite your attention for a brief moment—for I have kept you all too long from the main theme of the paper.
In the study of mechanics as in the study of astronomy we must begin with the Greeks. Thus, we find Aristotle attempting to teach the law of falling bodies, and also giving the reason why heavy bodies