Historical Relations i 3 5 



in the event of a refusal, to command him to abstain altogether 

 from teaching or defending or even discussing these opinions. If 

 he do not acquiesce he is to be imprisoned." A few days later a 

 decree was issued ordering the work of Copernicus to be " suspended 

 until corrected." 



During the following years the agitation against Galileo 

 gathered further strength. In 1623, however, something was 

 hoped by him and his supporters from the accession to the Papal 

 throne of Urban VIII, who as Cardinal had appeared not unfriendly 

 to scientific research in general and to Galileo in particular. In 

 1624 Galileo visited him but failed to obtain promise of any tolera- 

 tion, even in a passive form, for the new doctrines. For the next 

 six years little was heard publicly from Galileo on the subject. 

 Then in 1630 he broke silence and between that date and 1633 

 was played the final scene in the great drama of his contest with the 

 Church. 



By the beginning of 1630 Galileo had after many years' work 

 completed the composition which was finally published as the 

 " Dialogue on the Two Chief Systems of the World " (i.e.^ the 

 Ptolemaic and Copernican). Galileo obtained an interview with 

 the Pope, who gave him to understand that no objection would 

 be raised to publication if certain conditions were accepted. The 

 more important of these may be thus set forth : 



{a) The title must clearly indicate the character of the book. 



[b) The subject must be treated from the theoretical standpoint 

 and this must be clearly set forth in the preface. 



[c) The book, being largely concerned with the tides, must be 

 made to terminate with the following argument : " God is all- 

 powerful. All things are thus possible to Him. Therefore the 

 tides cannot be adduced as a necessary proof of the double motion 

 of the earth without limiting His omnipotence." 



The suggestions were accepted, as were some other minor 

 revisions and alterations made by an official, and this great work 

 was issued at the beginning of 1632. It is full of prophecies of the 

 development of cosmic theory. Thus, it foreshadows the concep- 

 tion of universal gravitation and of the first law of motion. We 

 turn, however, to those elements in the work which had a more 

 immediate effect on the attitude of the theologians. 



The dialogue is represented as between three persons, an open 

 advocate of the Copernican doctrine, an obtuse and obstinate 



