Extract from 'Of Colours'
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58 I tooke a bodkin {sic} gh & put it betwixt my eye & ye bone as neare to ye end of Backside of my eye as I could: & pressing my eye wth ye end of it (soe as to make ye curvature a, bcdef in my eye) there appeared severall white darke & coloured circles r, s, t, &c. Which circles were plainest when I continued to rub my eye wth ye point of ye bodkin {sic}, but if I held my eye & ye bodkin still, though I continued to presse my eye wth it yet ye colours circles would grow faint & often disappeare untill I renewed ym by moving my eye or ye bodkin.
59 If ye experiment were done in \a/ light roome so yt though my eyes were shut some light would get through their lidds There appeared a {illeg} or redish spot in ye midst at {illeg} greate broade blewish darke circle outmost (as ts), & wthin that another light spot srs whose colour was much like yt in ye rest of ye eye as at k. Within wch spot appeared still another blew spot r, especially if I pressed my eye hard & wth a small pointed bodkin. |& outmost at vt appeared a verge of light|
60 But on ye contrary if I tryed ye experiment in very darke roome ye circle ts apeared of of a {illeg} Reddish light sr of a darkish blew & ye middle spot r appeared lighter againe; & there {sic} seemed to be a circle of darke blew \tv/ wthout ye circle ts ye outmost of all [I conceive (in ye 60th experiment) where ye curvature \of ye Retina/ at ma & fn began & was but little ye blew colour tv was caused; at ab & ef where ye Retina was most concave, ye bright circle ts was caused: at bc. & de where ye Retina was not much incurved nor strained ye darke blew circle sr was caused & at cd where ye Retina was stretched & made convex ye light spot r appe was caused. In ye 59th Experiment ye spirits were str perhaps strained out of ye Retina at ab, ef, & cd or otherways made incapable of being acted upon by light & soe {illeg} made darker colours \a lesse appearance of light/ yn ye rest of ye {eye} Retina]