Porta, on the Reflection of Cold ^c. 171 



application of the pendulum to clocks, spake of it, in like 

 manner: Horolog. Oscillat. 1673, parti, p. 7> and part iv. 

 p. 151 ; and the Royal Society of London proposed to adopt 

 it." The learned Encyclopedists then go on to mention 

 the similar proposal oi Amontons in 1703, and others of a 

 later date, particularly that of ili. Condayn'ine, who in 1747 

 very philosophically recommended the equatorial pendulum, 

 as preferable to all others, for an universal standard. 

 M. Berthoiid, in his late excellent piece above quoted, as- 

 signs the san:e date (16/3) to the proposal of Huifgens, in 

 p. 151 ; and, in the title of his 2d article, which is ^'^ JMo7/ens 

 d'etallir, Sec. Away to establish an universal and perpetual 

 measure, by a pendulum, proposed by Hinjgcns in 1613." 



Thus it appears tliat {Fright proposed the derivation of 

 an universal standard from the mensuration of the meridian 

 in 1599, and Monion not till 1670; and that Sir Chris- 

 topher PVren reconnnended the pendulum some years before 

 1668; Moittoji in ]670; and Hmjgcns not till 1673. 

 How viany years before 166S*, I cannot say; for Sir Chris- 

 topher did not publish any of his numerous discoveries him- 

 self; but many of them were recorded or epitomized in the 

 Philosophical Transactions, and in the works of IFatlis and 

 otiicrs. Not having the early volumes of the Transactions 

 nt hand, I have searched in vain for .S7;' Christopher's pro- 

 posal, now in question, throughout the'first seven volumes 

 of the old Abridgement, which for want of a good index 

 (for it has several bad ones) is mere " confusion worse 

 'onfounded." / 



Thus the mere date of Wilklns^s " Real Character," though 

 a reprint, carries JVren's claim decisively beyond those of 

 both Mouton and Hiiygtns. 1 may add, as the book is 

 before me, that Dr. Sprat includes, in a catalogue of the 

 original discoveries of Wren, " a natural standard of mea- 

 sure from the pendidum ;" for he savs '' vt was never before 

 attempted f-" Dr. Derhavi is equally explicit in favour of 

 Wren. His words are: ('i'he pendulum) " to be, as Sir 

 Christopher IVren first proposed, a perpetual and universal 

 measure and standard, to which all lengths may be reduced, 

 and by which they may be judged of in all ages and coun- 



'* I rnij<lit say It/fare j666, vvlien IVUiim's fust inipiession wis burnt. 



+ Sprat's Hist, of the R. Society, pp. 147. 3 14, edit, id, 1703. This 

 history contains scarcely any datci\ but in his i20tli pace the autlior says 

 he was jntcrniptcd in writinj; it by the plague in Lojulon in 1665, and 

 ihc tire in 1^66. Dr. Hut/on siiys, in liis art. IFun, iliat S/irat brings 

 down the Society's Transactions to 1665, when it iiad existed nboat 

 twenty years, though only about five with a charter. 



7 tries. 



