CHAP. 2. 17. HEIGHT OF CLOUDS. 91 



order of them is inverted : many instances of 

 which may be found by consulting journals. 

 I have seen the cirrus in tufts moving along 

 rapidly in the wind, below cirrocumulus, and 

 even cumulus in a higher region. Towards 

 evening on Sunday, April 12, 1812, I observed 

 from Clapton a small fibrous cirrus moving 

 rapidly along in the wind, lower than fleecy 

 cirrocumulus which appeared in a comparatively 

 calm region above. There were, however, other 

 cirri more elevated in the sky at the same time. 

 The following spring, on Sunday, the 21st 

 March, 1813, at Cambridge, about 11 A. M., I 

 remarked a long cirrus moving rapidly along 

 in a North wind, not lengthways, but abreast. 

 At one end of it fibres pointed backward to the 

 North, while at the other they pointed to the 

 East. Higher up, light cumuli passed over from 

 the South ; and higher still were flimsy ill de- 

 fined masses of cirrocumulative cirrostratus in 

 an air comparatively calm, but they were 

 found to be passing over gently from North 

 West. Many other cases of inverted order 

 might be noticed. Sometimes cirrocumulus may 

 be seen under a spreading sheet of cirrus of a 

 milky appearance, which looks like a bas relief. 

 I have once or twice noticed the nubeculae of 



