C. _The Mock-Sun, all white, and far less shining, than the two others._ I. _A space very dark betwixt_ R. _and_ D. [Sidenote: * _Those _Five_ Suns, that appear'd the 29 _March_, A. 1629. at _Rome_, between 2 or 3 of the Clock, in the afternoon, were thus posited; that the two of them, which were in the intersection of two Circles, appear'd in that of a Circle, which passed through the Sun's Diske, with another, that was _Concentrick_ to the Sun: as may be seen in _Figure III_. borrow'd (for the easier comparing them together) out of _Des-Cartes_ his _Meteors_, cap. X._] This Appearance is look't upon as one of the notablest, that can be seen, by reason of the _Excentricity_ of the Circle H D N, and because that the _Parhelia_ * were not in the Intersection of the Circle D E B O with the great Circle S C H N, but in that of the Semi-circle H D N. As for the two odd _Rainbows_; they appear'd at _Chartres_ the 10. of _August_, 1665. about half an hour past six in the Evening; and did cross one another almost at right Angles, as may be seen by _Fig._ IV. [Illustration] The Rainbow, which was opposite to the Sun, in the usual manner, was more deeply colour'd, than that, which cross'd it; though even the Colours of the first _Iris_ were not so strong, as they are now and then seen at other times. The greatest height of the stronger Rainbow, was about 45. degrees; the feebler Rainbow lost one of its Legs, by growing fainter, about 20 degrees above the stronger; and the Leg below appear'd continued to the _Horizon_. These Rainbows did not _Just_ decussate one another at right Angles; there was some 6 or 7 degrees difference. The fainter, seem'd to be a Portion of a great Circle; and the stronger was but a Portion of a small Circle, as usually. The Sun, at their appearance, was about 6 degrees high above the _Horizon_, and towards the 17 _Azimuth_ of the West, Northward. {222} The Observer, M. _Estienne_, notes, that, when he made this Observation, the River of _Chartres_, which runs very near from _South_ to _North_, was betwixt him and the Rainbow; and that he stood Level with this River, whence he was distant not above 150 paces: which he adds, that the Curious may the better judge of this Observation. * * * * * _A Relation of an Accident by Thunder and Lightning, at _Oxford_._ This was imparted by Dr. _Wallis_ in a Letter, written at _Oxford_, May 12, 1666. to the _Publisher_, as follows: