CATALOGUE. — PHYSICAL OPTICS, 



305 



Macfait. Ed. ess. I. 29". 



October. 



Musschenbroek. A. P. 1753.11. 7.5. 



A parhelion about 30° from the sun, with arcs crossing 

 in it. 

 Boscovich on a halo. A. P. 1754. H. 32. 



No clouds were visibk, but the sun was obicure. 



NoUet. A. P. 1755. H. 37. 

 Braun's observations in Siberia. N. C. Pctr. 

 VI. 425. X. 375. 



One March J760, 21° above the sun 25° below it; 

 another in August, the thermometer 65.6° F. in the 

 shade: thin clouds floating from e o'clock to two. 

 Pingre. A. P. 1758. H. 23. 

 Moeren. Coll. Acad. VI. 299. 

 Barker on a halo. Ph. tr. 1761. 3. 



. H. 22°i. Vertical diameter of the external halo 45°, 

 with an elliptical curve 4° narrower or wider horizontally, 

 coinciding with it at the summit, without parhelia. May 

 30, 1737, {before 11, 



Aepinus; N. C, Petr. VIII. 392. 



An ellipsis, including the interior halo, touching it above 

 and below ; another with the horizontal diameter of the 

 ellipsis about 51°, the Yeitical 45°. 



Swinton on an anthelion. Ph, tr, I76I, 94, 



July 24, -very cold. 



Dunn on a parhelion. Ph. tr. 1763. 351. 



Many days in September and October. 



•Wales, Ph, tr. 1770. 129- 



There are constant parhelia in Hudson's Bay, the sun's 

 rising being preceded by two streams of light about 20" dis- 

 tant from him ; these accompany the sun the whole day 

 in the winter, with three parhelia. 



Saint Amans. Roz. XI. 377, 

 Atkins. Ph.tr. 1784.59- 



Terminating in a field of snow. 



Rozi^res on a paraselene. A, P. 1786. 44. 



With a tail. In a halo 7° or 8° in diameter, but not es- 

 sentially connected with it. 



Hamilton. Ir. tr. 1787. I. 23. 



An obscure light at 00°. Parh. 2e". 

 •Baxter on hales seen in North America, 



Ph, tr. 1787. 44. Fig. 



Ji. 33° i*'- An anthelion in the boiizontal circle, like a 



VOL. U. 



St. Andrew's cross : A second and third anthelion about 

 halfway between the first and the halo. 



Reynier. Roz. XXXVII. 308. 



23 Jul. 7 evening. 



Ussheron two parhelia, Ir, tr, 1789, III, 143. 



Parhelia at Caumont. Ph. M. I. 



Hall. Ed. tr. IV, 174. Nich. II. 485, Gilb. 



III. 257. 



A large circle not horizontal. Scheiner's was also oblique. 

 Wrede on a paraselene. Ph. M. XII. 346. 



Elliptic, the horizontal diameter being about 60°. 



*Lowitz. N. A. Petr. 1790. VIII. 384. 



At Petersburg, isJune 1700; the most complicated halos 

 and parhelia that have been observed. 



Sargeant on parheha in Cumberland. Nich. 



IV. 178. 



A third concentric halo. Ph. M. XII. 373. 



Not very circumstantially described. 



Englefield. Journ. R. I. II. 1. Nich. VI. 54. 



H. 24°, 48°. 



Brandes. Gilb. XI. 414. 



H. 21° to 22°. 

 See Weigelsgrundriss der cheniie. 



May 14, IS 04, J before 12 at night, I observed a lunar 

 halo, the internal limit passed nearly through gamma leonis, 

 but more accurately half way between gamma and Regulus. 

 Hence the distance from the middle of the illuminated part 

 of the raoon was accurately 21° 20' or 22', without a proba- 

 bility of an error of more than a few minutes. 



June 16, 1804. I saw a portion of a halo in the evening, 

 the clouds were light and high. 



Out of 58 of these observations 2 only were in July, 

 3 in August, 4 in January, 4 in September, s in March, 

 5 in June, 6 in February, 6 in October, 6 in December, 1 

 in April, and 9 in May. 



Theory of Halos and Par/ielia. - 



tHugens. Ph. tr. 167O. V. 1065. 



Hugenius de coronis et parhehis. Op. rel. 



II. 

 ♦Mariotte Trait6 des couleurs. Paris, 1 686. 



Oeuvr. I. 272. 

 Wood's theory of halos. Manch. M. ill, 



336. 



B t 



