observed at Leith in 1825. 89 



tance. The effect of the whole was exceedingly rich. — (See 

 this Journal, vol. iii. p. 55.) 



The morning of the 8th of July was clear, and the sun 

 shone very brightly. About noon, a thin sheet of cirrostra- 

 tus formed in the zenith, which did not sensibly diminish the 

 effect of the solar beams, neither could it be easily perceived ; 

 but its existence was rendered evident by the appearance of 

 a coloured halo, which remained till about 3 o'clock. It 

 consisted of a circle, which subtended an angle of about 45°, 

 and of an ellipse, tangential to this circle at the two extremi- 

 ties of its vertical diameter, the horizontal axis of which was 

 about 56°. At the two points north and south of the sun, where 

 the bands coincided, they were very vivid, and at one time as- 

 sumed quite the appearance of parhelia. The intensity of the 

 colours diminished in both towards the east and west ; and in 

 these quarters it was that the halo first began to fade. Ther. 

 59°.0, sol. rad. 45°, "Bar. 30.08, falling. Wind east, moderate. 

 17th August. — After a very wet day, during which 

 the temperature remained steadily at 59°, and the barome- 

 ter at 29-75, a display of the Aurora Borealis was seen at 

 10 p. m. It was neither vivid nor long continued, and pre- 

 sented only the usual appearances of that meteor. In allusion 

 to the notice of this observation, inserted by Mr Foggo and 

 myself in the Edi?iburgh Philosophical Journal, the same 

 writer in the Annates de Chimie, whose words I before quoted, 

 says, — " I suspect that this was the termination of an Aurora 

 Borealis of the day ; I find, in fact, that, on the morning of 

 the 17th, at half-past eight o'clock, the declination was cer- 

 tainly about 5' greater than the mean of the month at the 

 same hour ; whilst, in the evening, the needle had returned to 

 its ordinary position ;" and he adds, — " In this same month 

 of August, on the night of the 21st, the morning of the 22d, 

 the night of the 26th, and, particularly, on the night of the 

 29th, great anomalies were observed in the extent of the oscil- 

 lations of the needle. On all these occasions, the sky was, I 

 believe, clouded at Leith. If not, and the observers there did 

 not see the aurora, for instance, on the night of the 29th of 

 August, we will be obliged to admit, that there exist other 

 causes, of which we are still ignorant, which exert a considera- 



