Of Colours, Experiment 7

From Cambridge University Library Add. MS 3975.

7 Taking a Prisme, (whose angle fbd was about 60^gr into a darke roome into w^ch y^e sun shone only at one little round hole k in such manner y^t y^e rays, being equally refracted¨ at (n & h) their going in & out of it, cast colours rstv on y^e opposite wall. The colours should have beene in a round circle were all y^e rays alike refracted, but their length to about 7 or eight inches, & y^e centers of y^e red & blew, (q & p) being distant about 2 3/4 or 3 inches. The distance of y^e wall trsv from y^e Prisme being 260^inches.

This experiment may have been carried out in the study of Woolsthorpe Manor.