<45r>

Cambr.
Decemb 14th. 1675.

Sr

The notice you gave me of ye R. Societie's intending to see ye expt of glass rubb'd to cause various motions in bits of paper unde{illeg}|r|neath, put me upon recollecting my self a little further about it, & then remembring yt if one edge of ye brass hoop was laid downward ye glass was as neare again to ye table as it was when ye other {illeg}|e|dge was laid downward & yt ye papers plaid best when ye glass was nearest to ye table: I began to suspect yt I had set down {illeg}|a| greater distance of ye glas from ye table then I should have done, for in setting down yt experimt I trusted to ye Idea I had of ye bignes of ye hoop \in wch I might easily be mistaken having n{illeg}|o|t s{illeg}|e|en it of a long time/. And this suspicion was increased by trying ye experimt wth an object glass of a Telescope placed about ye 3d part of an inch from ye Table: for I cou{illeg}|l|d not see ye papers play any thing neare so well as I had seen them formerly. Whereupon I lookt for ye old hoop wth its' glas, & at length found ye hoop ye glass being gone, but by ye hoop I perceiv'd that when one edge was turnd down ye glas was almost ye third part of an inch from ye table & when ye other \edge/ was down wch made ye papers play so well ye glass was scarce ye 8th part of an inch from ye Table. This I thought fit to signify to you that if ye expt succeed not well at ye distance I set down it may be tryed at a less distance, & that you may alter my paper & write in it an eighth part of an inch instead of $\frac{1}{2}$ or $\frac{1}{3}$ of an inch. The bits of paper ought to be very little & of thin paper. <45v> Perhaps little bits of ye wing of a fly or other light substances m{illeg}|a|y do better then paper. Som{illeg}|e| of ye motions as that of hanging by a corner & twirling about, & that of leaping from one side of {illeg} part of ye glas to ye another \wthout touching ye table/ happen but seldom but it made me take ye more notice of them.

Pray present my humble service to Mr Boyle \wn you see him/ & thanks for ye favour of ye convers I had wth him at spring. My conceit of trapanning ye common Ether, as he was pleas{illeg}|d| to expres it, it makes me beg{illeg}|i|n to have ye better thoughts on yt he was pleasd to entertein it wth a smile. I am apt to think yt wn he has a set of expts to try in his air pump, it will he will make that one to see how ye compression {illeg} or relaxation of a muscle will shrink or swell, soften or harden, lengthen or shorten it.

As for Registring ye two discourses you may do it, only I desire you would suspend till my next letter, in wch I intend to set down something to be altered & something to be added in ye Hypothesis, being in ye mean while

Sr

Yor humble Servant

Is. Newton.

<45av>

For Henry Oldenburg Esq at
of ye old Pal-mall
in Westminster

London

|2|

|Mr Newton to Mr Oldenburg concerning an Experiment of gl{illeg} glas rubbed to cause various motions in litle bits of paper underneath ye glas.|