<4v>

Sir I have here sent you the letter I promised concerning these series. It is blotted in some places but rather then write it over fair, I have set down here the 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: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 the Postscript to the R. societie's tryal of the Experiment, I desire you would be pleased to send me some short information about their tryal: particularly the shape of their Image as to length & breadth, & the angle of {their Prism conteined} by the refracting sides, & whether they caused that angle to be very exactly measured, or {esteemed it by guesse} a less exact measure to be any number of degrees . For I imagin the difference between me & Mr Lucas lies either in the different angles of our Prisms; or in this that he perhaps measures the length of the Image by the streight sides, I by the middle line or axis; or in both together. In his experiments which he urges against me you'l find want of circumspection. Sir I am in hast

Is. Newton.

Cambridge

June 13 1676

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