50 Notice of the Rarer Atmospherical Phenomena in 1824. 



midity ; and, during this period, the cymo'id cirrostratus was 

 very prevalent. 



In February, we had very variable and stormy weather. 

 Temperature lower than in January ; quantity of rain, 1.81 

 inch. Vegetation was much retarded, and diseases of all 

 kinds prevailed. 



On the 1st, The following observations were made on the 

 Formation of Clouds. About an hour after sunrise, the sky 

 was partially overcast by lengthened cumuli, leaving rather 

 wide spaces between them quite free from clouds. The colour 

 of the sky was then equal to the 18th degree of Saussure's 

 Cyanometer. These large cumuli, urged by a very gentle 

 wind, were in motion towards the N.E. ; and it was seen, that 

 one of them, which moved over a wide free space of the hea- 

 vens, at the elevation of 50°, was furnished with pendant cir- 

 rose streamers. The portion of the sky over which it moved, 

 had been for a considerable time quite free from clouds ; but 

 whenever this cumulus approached it, several minute strips of 

 cloud suddenly appeared in various parts. These quickly in- 

 creased on all sides, and inosculating, formed together a large 

 cumulus, which immediately began to move upwards, and, in 

 fine, was blended intimately with the larger one, which con- 

 tinued moving to the N.E. : all this passed in four or five mi- 

 nutes. Immediately after the inosculation of one subordinate 

 cumulus, another and another formed in the same manner, and 

 were likewise attached to the larger one. When it had near- 

 ly passed, a few other flocculent masses began to form, but on 

 attaining a moderately large size, they were suddenly redissolv- 

 ed. The sky now assumed a much lighter tint in that 

 quarter, the colour not being equal to 18° of Saussure, and 

 some other masses still continued to form ; but they were 

 enlarged with extreme slowness, and retained, for a long time, 

 a thin spongy form, and so were carried onwards by the aeri- 

 al currents. (Therm. 40°, Bar. 29.80.) 



The 11th of Feb. produced a most singular phenomenon. 

 About noon, when the sky was rather free of clouds, the 

 pressure considerable, (Bar. S0.40.,) and the wind, W., gen- 

 tle, there appeared in the north-east, an extensive cirrostratus, 

 completely and distinctly divided in a perpendicular direction, 



