observed at Gotha on the 12lh of May 1824. 107 



Another circle KGL appeared with very brilliant colours, 

 and, touching the circle AHGIB in the point G, the red of 

 its outer border being turned towards the sun, and the green 

 being in its inner circumference. This circle seemed to me 

 to have a radius smaller than that which immediately sur- 

 rounded the sun. It is possible, however, that, from an op- 

 tical illusion, they might appear of different sizes, though 

 their magnitude were the same. The upper circle KGL was 

 not complete, from the want of white clouds to receive it; 

 but at the part where it touched the other circle, and at some 

 distance beyond its two sides, the colours had an extraordi- 

 nary brilliancy. 



The Zenith was nearly at Z. A great shining circle 

 S S"" S'"" S""" passed through the centre of the true sun and 

 the two parhelia S' and S". It was parallel to the horizon, 

 and had its centre in a line which passed from the Zenith to 

 the Nadir. The two parhelia S' S" were confounded with the 

 small tails opposite to the sun. The parhelia appeared at A 

 and B. 



This great horizontal circle did not appear at the beginning 

 of the phenomenon. Some parts of it appeared at the parhe- 

 lia. It was quite entire at 7 h . 



Three parhelia S"" S'"" S""" appeared upon this great cir- 

 cle ; the two first being 90° from the real sun, and the last 

 180°. They were white and iheir light feeble. 



Two luminous arches OP and QR, which seemed to be 

 portions of two great circles cut the false image of the sun at 

 right angles. M. Kreis saw them differently, as shown in 

 Fig. 16. He says that they crossed the horizontal arch 

 nearly in a vertical direction. 



Professor Kreis observed the portion of a circle MS'"N a 

 little after seven o'clock, and Dr. Buch saw it re-appear near- 

 ly at eight o'clock. 



This singular parhelion began to appear at 6^ h , M. de 

 Hoff saw it at three quarters of an hour after 6". At 7 h in the 

 morning the barometer stood at 27 inches 1 line 4. At 5 h in 

 the morning the thermometer was +2° Reaumur, 36|° of 

 Fahrenheit, so that at no great height in the atmosphere the 

 temperature must have been so low as freezing. 



