Invention of the Pendulum or balance Spring, amyt 



giving a wrong account of the bufinefs in qtiejlion, but all the others, as Perthenjisy Londi- 

 nenfts. It becomes neceflary to mention this, from the manner in which the conduftor of 

 tlie fupplement to the Encyclopedia Britannica has introduced the fiibjefl: in queftion. 



Believe me, 



With great refpedV, 

 Tour's, &c. 



N.L.* 



XII. 



On the Inventions of Robert HooKEfor regulating Time Pieces, By a Correfpondent. 



> 



To Mr. NICHOLSON. 



SIR, 



London f July 15, iSoo. 



XN that fcarce publication of the famous Robert Hooke, entitled " A Defcription of 

 JHeliofcopes and fonie other Inftruments," printed in quarto, for Robert Martyn, printer to 

 the Royal Society, 1676, I obferve (befides the heliofcopes by repeated reflexions of the 

 folar light, and the univerfal joint at prefent fo well known and efteemed) a poftfcript 

 refpefting the regulation of time pieces by a fpring, of which I fend you an abflraft, in 

 hopes that fome of your ingenious readers will inform the world, whether any farther 

 difclofure was ever made of the fubjecSl there hinted at ; and alfo that fome of your cor- 

 refpondents, who underftand the univeifal and real character of Bifliop Wilkins, will 

 tranflate the communication of which I fend you a faithful copy. It feems to me as if this 

 wonderful man had been well acquainted with all that'has fince appeared as the particular 

 difcaveries of individuals during the laft century. 



The author firft vindicates his title to the invention of what is now called the pendulum 

 fpring, contrived by him in 1658, and made the fubjefl: of a treaty between himfelf and 

 fome men of fortune, in 1660, which broke off upon their infifting that he Ihould have no 

 fhare in fuch improvements as might be afterwards made on his principles. They aiTured 

 him that his invention would be difcovered by others in fix months, to which he 

 anfwered, he would give the world feven years; and he remarks, that more than fourteen; 

 had elapfed without that effcO: taking place. 



In 1664, at the earneft entreaty of a friend, the doctor read feveral of his firft Cutlerean 

 leftures on the fubjedl of time pieces, and fhewed the ground and reafon of the applications 

 of fprings to the balance of a watch for regulating its motion, as the fame time that he 



• I am forty that this letter having been miflaid, renders it neceffary to apologize to fo valuable a cor- 

 refpondent. 



3 explained. 



