CATAIOOUE. — PHVSICAi:, OPTICS. 



303 



In lat. 96' 45' the sun was three diameters above the ho- 

 rizon, 14 June at midnisht. The Dutch are said to have 

 seen it 4° too high in Nova Zembla. At Stockhelm the 

 horizontal refraction is sometimes 47'. 



Mairan on llie sun apj)eaiing oval at 10° al- 

 titude. A. P. 1733. 329. H. 23. 



Elliptic appearance of the sun at a consider- 

 ablehcight. A. P. 1741. H. 134. 



Dicquemare on a distorted iris. Roz. X. ISG. 



Probably by irregular refraction. 



Beams of Light from Atmospherical Refrac- 

 tion or Reflection. 



Hevelius on a mock sun and a vertical train 

 of light seen in Russia. Ph. tr. IG74. IX. 

 26. 



A red mock sun below the real sun, and a vertical train 

 from the sun upwards. At first the mock sun was at the 

 distance of a few degrees, at last the sun descended and 

 united with it. A severe frost followed. 



Derham on a pyramidal light. Ph. tr. 1707. 

 2411. 



April 7, 1707, after sunset, perpendicular to the horizon, 

 succeeded by a halo. I have also observed such a beam in 

 June. Y. 



Messier on two vertical cones of light at- 

 tached to the moon. A. P. 1771. 434. 

 The moon being covered with thin clouds. 



Gilbert on a singular meteor. Giib. III. 360. 



A perpendicular beam of light above the sun after sunset, 

 in August. 



Remarks on the zodiacal light. Zach. Mon. 

 corr, VII. 



Observations of Parhelia^ or Paraselenes, and 

 Halos of about 22° or 44°, in general. 



Zahn Mundi oeconomia. 2 v. f. M. B. 

 Li/coithenis chronicon prodigiorum. f. Bas. 



1557. M. B. 

 Fritsck on meteors. 



Particular Accounts. 



In order of time, with the angles, where they have been 

 measured. 



Roman parhelia. Descartes meteorol. C. X. 

 Journal dessavans. 1666. Ph. tr. l665 — 6.1. "" 



219. 

 Brown on parhelia in Hungary. Ph. tr. 



1669. IV. 953. 



Observation of the French academy. Ph. tr. 



1670. V. 1065. 



A halo 22" 0'. 

 Petto on parhelia at Sudbury. Ph. tr. I699. 



XXI. 107. 



Stephen Gray on parhelia at Canterbury. 



Ph. ,r. .699. XXI. 126. X^^fUm^. 



H. 23» O'. /7 ^ " "" ^ 



Lahire. A. P. II. 208. ' ■ — VKKS'TV , 



Lahire. A.P. X. 47. 



H. n. 1. 21" 30'. n. a. 23" 20'. n. s. aa" 45'. n. 4. 

 21° 0'. 

 Cassini and Grillon. X. 152, I68, 275, 454. 



A circle 22" above and 23° below the sun, 168. 

 A. P. X. 411. 



Chazellesand Feuillee. A. P. I699. H.82. 

 St. Gray on a parhelion and halo. Ph. tr. 



1700. XXII. 535. 

 ♦Halley. Ph. tr. 1702. XXIfl. 1127. 



The arches touching the halo appeared to be portions of 

 circles having their centres near the opposite side ofth« 

 halo : the upper one was continued across the horizontal 

 circle, and at the intersections were parhelia 31 °i. distant 

 from the sun. The sun's altitude was from 40° to 4S°. 

 The clouds were seen to drive under the circles : they were 

 therefore formed high in the atmosphere. 



A circle at Clermont. A. P. 1708. H. 109. 

 Cassini. A. P. 1713. H. 67. 

 Halley. Ph. tr. 1721. XXXI. 204. 



The air apparently replete with snowy particles. Ok- 

 serves, that an explanation " seems wanting." 



Whistoa. Ph. tr. 1721. XXXI. 212. 



An inverted arch not much bent touched the halo. The 

 external tangent arch was without a halo, it seemed 00° 

 long: its centre near the aenith ; sun's altitude 23°i, distance 

 of the extctnal arch from the zenith 2o°. The halo became 



