CORRESPONDANCE. 1664. 171 



pended by a very curions hair, which feems as likely a way as any to find eut to 

 what point of the globular body, hung at the end of a ftring, the length of fuch a 



pendulum is to be reckoned. Monfieur Zulichem fays , it is - parts of a third 



proportional below the center of the bail c, the firft of which proportionals are, 



ab + bc (that is, ac^ and bci namely, ab H- bc^ bc : : bci —, j--, which we 



ab -\- bc 



will fuppofe ce-^- of which taken below the centre gives// the point, to which 



the length of the pendulum ad is to be meafured from ^ , the point of fufpen- 

 fion. Sure it is, that this point is below c, the center of the body; but whetherat 

 ^, I cannot pofitively y et affirm. 



The plate for your book ^) was graven before I received your lail of Monfieur 

 Evelyn's. I hâve only taken notice of feven inftruments, which you in thofe fhcets 

 I looked on hâve defcribed; and thofe I fo put into one fmall plate, that they will 

 fold out of the book, when there is occafion. This lail of Monfieur Evelyn î») I 

 hâve given a fmall draught of alfo to the engraver, who is not an Englifhman, but 

 one that I find a very good workman, and very punéhial to his word; which was 

 the reafon I did not eniploy Mafter Faithorne, as you direéted, he having fo 

 very often and often difappointed my expcdation. I hâve fince my lafl: made an 

 anatomy of a dog, and hope, that I hâve madc a confiderable new difcovery; but 

 this being the firil time I hâve feen it, at leafi: taken notice of it, I cannot, till fur- 

 ther trial, pofitively affirm any thing, which, as foon as ever I am afl^ured of it, you 

 fhall thereof receive an account from. 



Sir 



Your moft faithfnl and moft humble fervant 



R. HOOKE. 



I hope. Sir, you will pardon this harty fcribble, for it was very near elcven a 

 clock this night, before I could get from fome company, met '°) about th'e bulinefs 

 of Sir J. Cutler. 



8) L'ouvrage cité dans la Lettre N°. 1 289 , note 6. 



^) Probablement pour son ouvrage: 



Kalendarium Hortenfe. London. Printed by Jo. Martyn and Jac, AUerftay, Printers to 

 the Royal Society, and are to be sold attheir shop at the Bell in St. Paul's Church Yard. 

 MDCLXiv. in-folio. 



'°) Dans la séance de la Société Royale du 7 décembre 1664 (V. st.), sir W. Petty, Dr. Wilkins 

 et W. Graunt furent chargés de rédiger le programme des cours de R. Hooke et de le mon- 

 trer à sir J. Cutler, le fondateur de ce „lecturerfhip"\ pour en savoir son opinion. 



