<4v>

Sr I have here sent you ye letter I promised concerning these series. It is blo{illeg}|tt|ed in some places but rather then write it over fair, I have set down here ye places less legible. p.1, l: 17, ${\stackrel{‾}{P+PQ}}}^{\frac{m}{n}}$. lin: 34, ${\stackrel{‾}{cc}}}^{\frac{1}{2}}$. p. 4, l: 35, $\frac{{CB}^{q}}{CD}$. lin 36, $\frac{1}{14rr{c}^{4}}$ p: 6, l:{illeg}3, $+\frac{14{x}^{5}}{2025{a}^{4}}+\frac{604{x}^{7}}{893025{a}^{6}}$ p: 7, l 14, Quare $AG=\frac{3}{2}d-\frac{1}{5}x-\frac{12xx}{175d}-vel+\text{&c}$. lin: 40, in DP cape $DM=\frac{3{AD}^{q}}{4AK}$. lin 42 $\frac{4AN+A\beta }{15}×4AD$, lin 43 $\frac{21AN+4A\beta }{75}×4AD$.

I received yours concerning Mr Lucas, for whom I intend an answer. But he referring in ye Postscript to ye R. societie's tryal of ye Expt, I desire you would be pleased to send me some short information about their tryal: particularly the shape of their Image as to length & brea\d/th, & ye angle of {their Prism conteined} by ye refracting sides, & whether they caused yt angle to be very exactly measured, or {esteemed it by guesse} a less exact measure to be 60 \any number of/ degrees more or less. For I imagin ye difference between me & Mr Lucas lies either in ye different angles of our Prisms; or in this that he \perhaps/ measures ye length of ye Image by ye streight sides, I by ye middle line or axis; or in both together. In his experiments wch \he/ urges agt me you'le find want of circumspection. Sr I am in hast

Is. Newton.

Cambridge

June 13 1676

|Rec. June 13. 76. Answ. june 17. 76.|