1 so 0)1 the Rate of Clocks. 



mean daily rate +0'-33, and for the least +0'"1 1, and the mean 

 of these five periods is -f 0''216 as the mean daily rate. 



These two clocks coming to keep time so close and near to- 

 gether, and for such a length of time, was a matter merely acci- 

 dental : I should consider it a very vain pursuit, to attempt to 

 make any two clocks do so, nor do I think that there is any pro- 

 bability of my seeing the like to take place again. It is not im- 

 possible to make two clocks to go very nearly together, and for 

 a considerable length of time too, but in this veiy nearly, and 

 in that g'/ile close, tlieie is a very wide difference. 



It has been said in some of the numbers of your Phil. Journal, 

 where I think that I have seen it, that a clock with a dead 

 beat sca)5ement was made by the late Mr. Grignion, and given 

 by him to the Society for the Encouragement of Arts, Manu- 

 factures, &c. " that any addition or diminution of the motive 

 force would produce no alteration in the time-keeping of the 

 clock." Now, sir, being well acquainted with the principle of 

 the dead beat scapemeut, I cannot easily admit this. When 

 this circumstance was mentioned, it should surely have been 

 stated hi what manner this was obtained by Mr. Grignion, in 

 the dead beat scapement. Where this takes place in any scape- 

 ment, I humbly presume it can then no longer have the pro- 

 perties of tliat of the dead beat scapement. However, if you 

 or any of your correspondents will have the goodness to take 

 the trouble to explain this, it will be estef'med a considerable 

 favour. 



From the same respectable authority of Mr. Grignion, we are 

 informed that in the year IG41 a clock was made and put up 

 in the church of St. Paul's, Covent-garden, by a Richard Harris, 

 who had applied a pendulum to it. This is rather singular, con- 

 sidering the cavilling which took place many years afterwards, as 

 to the priority or right of having first applied the pendulum to 

 a clock. Father Alexander tells us, that there were no clocks 

 made with pendulums to them in Paris, till after the year 1660 ; 

 and yet there was a duodecimo pamphlet of Galilei's, On the 

 nature and properties of pendulous bodies, translated from the 

 Italian into French, published at Paris in 1639. May we not 

 hazard a conjecture for Richard Harris in this case ' Our coun- 

 tryman Inigo Jones travelled twice into Italy, and was at Venice, 

 about the time that Galilei was there. It is not improbable 

 that Mr. Jones when there may have heard of what Galilei had 

 suggested regarding the pendulum, and of the "propriety of ap- 

 jilying it to a clock, and afterwards may have communicated 

 these ideas to Richard Harris on his returning to London. It 

 niuot be observed, that Inigo Jones was not in life at the time 



when 



