1893.] President's Address. 379 



went to Cambridge to consult Mr. Newton on the subject of the pro- 

 duction of the elliptic motion of the Planets by a central force,* and 

 011 the 10th of December of that year he announced to the Royal 

 Society that he " had seen Mr. Newton's book, ' De Motu Corporum.' " 

 Some time later, Halley was requested to " remind Mr. Newton of 

 his promise to enter an account of his discoveries in the register of 

 the Society," with the result that the great work ' Philosophise 

 Naturalis Principia Mathematica ' was dedicated to the Royal Society, 

 was actually presented in manuscript, and was communicated at an 

 ordinary meeting of the Society on the 28th of April 1686 by Dr. 

 Vincent. In acknowledgment, it was ordered "that a letter of 

 thanks be written to Mr. Newton, and that the printing of his book 

 be referred to the consideration of the Council ; and that in the 

 meantime the book be put into the hands of Mr. Halley, to make a 

 report thereof to the Council." On the 19th of May following, the 

 Society resolved that "Mr. Newton's k Philosophise N"aturalis Principia 

 Mathematica ' be printed forthwith in quarto, in a fair letter ; and 

 that a letter be written to him to signify the Society's resolution, and 

 to desire his opinion as to the volume, cuts, &c." An exceedingly 

 interesting letter was accordingly written to N"ewton by Halley, 

 dated London, May 22, 1686, which we find printed in full in Weld's 

 * History of the Royal Society* (vol. 1, pp. 308309). But the 

 Council knew more than the Royal Society at large of its power to do 

 what it wished to do. Biology was much to the front then, as now, 

 and the publication of Willughby's book, * De Historia Piscium,' had 

 exhausted the Society's finances to such an extent that the salaries 

 even of its officers were in arrears. Accordingly, at the Council 

 meeting of the 2nd of June, it was ordered that " Mr. Newton's book 

 be printed, and that Mr. Halley undertake the business of looking 

 after it, and printing it at his own charge, which he engaged 

 to do." 



It seems that at that time the office of Treasurer must have been 

 in abeyance ; but with such a Senior Secretary as Dr. Halley there 

 was no need for a Treasurer. 



Halley, having accepted copies of Willughby's book, which had 

 been offered to him in lieu- of payment of arrears of salaryf 



* Whewell's ' History of the Inductive Sciences,' vol. 2, p. 77. 



f It is recorded in the Minutes of Council that the arrears of salary due to 

 Hooke and Halley were resolved to be paid by copies of Willughby's work. 

 Halley appears to have assented to this unusual proposition, but Hooke wisely 

 " desired six months' time to consider of the acceptance of such payment." 



The publication of the ' Historia Piscium,' in an edition of 500 copies, cost the 

 Society 400. It is worthy of remark, as illustrative of the small sale which scientific 

 books met with in England at this period, that, a considerable time after the publi- 

 cation of Willughby's work, Halley was ordered by the Council to endeavour to 

 effect a sale of several copies with a bookseller at Amsterdam, as appears in a letter 



