Prof. Wartmann on two Extraordinary Meteors. 177 



colours sparkled so that it was impossible to determine the 

 spot where the separation of the tints between the two arcs 

 took place. The development of these various phases com- 

 menced at a quarter to six o'clock ; the last continued eight 

 to ten minutes, and all vanished some instants before sunset. 

 Mr. Frederick Chavannes, mathematical instructor in the 

 Gymnasium of Lausanne, and member of the Society of Na- 

 tural Sciences in that city, witnessed this phaenomenon, and 

 agreed in describing it as I have done. 



Does this extraordinary eccentric arc proceed from a second 

 illuminating point placed at the same height as the sun, or 

 from a very resplendent nubilous band? I am inclined to 

 think that it is produced by the reflexion of the luminous 

 rays on the surface of the lake. This circumstance, in dimi- 

 nishing their intensity, must have caused all trace of the ex- 

 ternal arc to disappear. The little height of the eccentric 

 above the common arc will be explained, on this hypothesis, by 

 the short distance of the luminary from the horizon. Lastly, 

 we may compare the appearance of which I have spoken to 

 that of other bows which have been observed in analogous 

 circumstances, such as that of the 10th of August 1665, ob- 

 served by the Canon-Etienne on the banks of the Eure, near 

 Chartres; that of the 17th of August 1698, which was ob- 

 served by Halley at Chester, in the vicinity of the Dee ; that 

 of the 8th of August, 1 74-3, so well described by Celsius, who 

 witnessed it at Husbi, in Dalecarlia, on the left bank of the 

 Dale, &c. All these meteors, and that of the 25th of April, 

 occurred between the hours of six and seven in the evening. 

 But the very regular spectral coloration of the portion com- 

 mon to the two arcs has still to be accounted for. The cause 

 of its being more brilliant than the rest is explained by the 

 superposition of the refracted rays in relation to the observer ; 

 but how are the two partial spectres expanded so as only to 

 form one of twice the width ? 



The second meteorological phaenomenon was seen in all 

 its beauty on Saturday the 30th of May last. The Bise had 

 blown the whole day, and not a vapour obscured the perfect 

 clearness of the sky. The moon was only five days old. 

 Shortly after sunset I remarked and pointed out to several 

 persons who were with me, a very luminous band of that deep 

 red which sometimes tinges the clouds in the west. It was 

 single, vertical, and about 35° high. It presented no appear- 

 ance of divergence; on the contrary,. its sides, exactly parallel, 

 were distant 1^° to 2°. It rested on the perfectly defined 

 ridge of the Jura, near the spot where the sun went down. 

 From this inferior limit, its brilliancy remained sensibly con- 



