of Cumulus, Cirrus, and their Varieties. 367 



motion, very slightly inclined to the n.e., while the motion 

 of the lower range was due e. Upon comparing these mo- 

 tions with that of the fibrati, and taking into consideration 

 the position of the fibrati, it appears probable that their mo- 

 tion was not occasioned by wind. (?) As some of the speci- 

 mens of fibratus approached the s. e., they presented the 

 appearance of a brush, the head of which was bounded by 

 curvilinear fibres, and directed to the s. e., while the portion 

 towards the n. w. was drawn out into fine points, which 

 diverged from each other. It is worthy of remark, that the 

 velocity of these specimens was the same as the usual velo- 

 city of the varieties of cirrus, which is much slower than the 

 usual velocity of cumulus. Whatever agent contributed to 

 the formation of these clouds, it is evident that it caused 

 them to move forward against the wind ; the motion of the 

 fibrati and cumuli being nearly opposite in direction, and 

 the fibres of the former being driven back by the current 

 against which they were advancing. A very clear afternoon 

 and evening followed : a few specimens of cirrus were noticed, 

 varieties which had not occurred previously to the exhibition 

 of fibratus. 



The mares' tails are usually regarded as an indication of 

 wind. I find in my journal the following remarks : — " May 

 29., 2 p. m. Little wind." At this time the cumulus usually 

 seen in foul weather, with a superior sheet of cloud, was 

 observed. "May 30. I and 2 p. M., Sunshine with wind. May 

 81., 1 and 2 p. m. Same, with the extended variety of cirro- 

 stratus and fibrus filiformis, a modification of cirrus." These, 

 with the usual occurrence of wind after displays of the aurora, 

 appear to connect these clouds with electricity. It is remark- 

 able, that the phenomena of wind should have been observed 

 at the time of the observation of crinis fibratus, the day be- 

 fore, at the same time, and the day after, also at the same 

 time. 



June 15. 1833. t— In the evening of this day, cirro-cumulus 

 was observed. The modifications noticed were, quintus, 

 quartus, and tertius : they were seen forming on a fine blue 

 sky, and gradually augmenting in size, as on May 3. At this 

 time, crinis fibratus was very prevalent, and was observed 

 both above and below the cirro-cumuli: the inferior specimens 

 were very well defined (similar to those of May 30.), and 

 drawn out into fine hairy-form points. I particularly remarked, 

 that the motions of the superior and inferior specimens were 

 identical, and that the motion of the cirro-cumuli crossed 

 their path at an acute angle. The cirro-cumuli, which had 

 been prevalent during the whole day, were moving w. by s. ; 



