Page:Philosophical Transactions - Volume 001.djvu/232

 H N. The two Mock-Suns, in the intersection of the Semicircle H D N, and the Circle S C H N: The midst of which two False-Suns was white and very luminous; and their Extremities towards D I ''were tinged with the Colours of a Rainbow. The False Sun, mark'd N, was fainter than that, which is mark'd'' H.

C. The Mock-Sun, all white, and far less shining, than the two others.

I. A space very dark betwixt R. and D.

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.

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.

Rh