ROYAL SOCIETY OF LONDON. 145 



In 1686 the MS. of Newton's immortal work, Philosopliice Naturalis Prtn- 

 dpia Matlicmatica, was presented to tlie Society ; and being accepted with 

 thanks, it was ordered "that the printing of the book be referred to the con- 

 sideration of the council, and that it be put into the hands of ]Mr. Hailey to 

 make a report thereof." The council, duly sensible of the slenderness of the 

 Society's finances at that time, were glad to devolve upon Ilalley, who agreed 

 to accept it, the " business of looking after and printing the Avork at his own 

 charge." In the course of the preparations for that purpose, it became neces- 

 sary for Ilalley to inform the author that Ilooke claimed to have " some pre- 

 tensions upon the invention of the rule of the decrease of gravity being recip- 

 rocally as the squares of the distances from the centre," though he admitted 

 the demonstration of the curves generated thereby to belong wholly to Newton. 

 When apprized of this claim, the illustrious geometer determined upon the sup- 

 pression of the entire third book of the Principia. "Philosophy," he said, "is 

 such an impertinently litigious lady, that a man had as well be engaged in law- 

 suits as have to do Avith her. I found it so formerly, and now I am no sooner 

 come near her again but she gives me warning." In the controversy relative 

 to his optical discoveries he had written to Oldenburg : " I intend to be no 

 further solicitous about matters of philosophy, and therefore I hope you will 

 not take it ill if you find me never doing anything more in that kind." It 

 required much remonstrance and entreaty on the part of Ilalley to induce New- 

 ton to abandon his intention of suppressing the third book, De Sijstcmatc Mundi, 

 without which the celebrated work might have borne the title, Dc m<Au Cor- 

 ponwi Libri duo. In view of all the circumstances it is difficult to deny the 

 justice of the remark made in Rcgaud's Essaf/ o?i the First Publication of the 

 Principia, that " it is hardly possible to form a sufficient estimate of the im- 

 mense obligation which tlie world owes in this respect to Ilalley, without whose 

 great zeal, able management, imwearied perseverance, scientific attainments, 

 and disinterested generosity the Principia might never have been published." 



Ilalley had been elected a Fellow of the Society in 1G73, on his return from 

 his voyage to St. Helena, made chiefly with a view to astronomical observa- 

 tions, of Avhich the fruit remains in his Catalogus stellarum australium, but 

 rendered subservient also to the science of terrestrial magnetism, of Avhich he is 

 styled by a high authority the father and founder. " To liim," says Sir John 

 Herschel, "Ave owe the first appreciation of the real complexity of the subject 

 of magnetism. It is Avonderful, indeed, and a striking proof of the penetration 

 and sagacity of tiiis extraordinary man, that Avith his means of information he 

 should have been able to draw such conclusions, and to take so large and com- 

 prehensive a vicAV of the stibject as he appears to have done." Ilalley's com- 

 munications to the Society on this subject consist of a chart, the first of its 

 kind, showing the A^aiiation of the compass, based on the idea of employing 

 curA'es draAvn through points of equal declination, and of papers published in 

 the ISOth and ]95th numberKS of the Philosnp/iical Tranm'iions. In the last 

 of these occurs a striking passage, in Avhich he expresses his belief " that he 

 has put it past doubt that the globe of the earth is one great magnet, having 

 four magnetical poles or points of attraction ; near each pole of the equator tAvo; 

 and that in those pails of the Avorld Avhich lie near adjacent to any one of those 

 magnetical poles, the needle is chiefly governed thereby, the nearest poles 

 being always predominant over the more remote." Amid the efforts Avhich are 

 noAv directed to this sitbject, it Avill not be uninteresting to observe Avith how 

 much modesty this early explorer defers the solution of his difficult problem 

 to later times. " The nice determination," he says, " of this and of several 

 other particulars in the magnetic system is reserved for remote posterity ; all 

 that Ave can hope to do is to leave behind us observations that may be confided 

 in, and to propose hypotheses Avhich after ages may examine, amend, or refute." 

 And he proceeds to urge upon all navigators and lovers of natural truths to 

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