CLOUDS. 443 



of the cirrus down to those nearest the earth where the fracto-cumulus 

 is produced, as the vapor of water passes from the state of frozen par- 

 ticles to that of aqueous globules, or vice versa. However, the pallio- 

 cunndus, which serves as a transition from the two types and their deri- 

 vatives, is found a little more elevated than the cumulus. 



I have thought it proper to modify Forster's nomenclature hy substi- 

 tuting names more in harmony with the form and nature of clouds. I 

 give, in continuation, the old and the new classification : 



Forster's nomenclatm-e. Poey'8 nomenclature. 



Cirrus Ctfj-Z-cloud Curl-cloud. 



Cirro-stratus Tr«»e-cloud. Thread-cloud. 



Cirro-cumulus Sonder-cloud - Curdled-cloud. 



Pallio-cirrus *S/ice<-cloucl. 



Cumulus Staclcn-cloud Mount-cloud. 



Pallio-cumulus Eain-cloud. 



Fracto-cumulus TTiJifZ-cloud. 



With the exception of cirrus, whose name c?«r^cloud approaches near- 

 est the form of that cloud, ail the determinations have been changed. 

 Tho, ])aUio-cu)nulus replaces the nimbus, also named rain-clond. ' 



I. — CiRKus, (Howard.) 



Curl-cloud — cirrus, so named by Howard, (the "cafs-tail" of sailors, 

 illustration Ko. I, figs. 1, 2,) is composed of filaments which resemble a 

 twisted tuft of curled hair, (illustration No. I, figs. 3, 4,) plumage, (fig. 

 5,) the flowing tail of a horse, (illustration liso. 11, fig. 0,) or a fine pencil, 

 (illustration E"o. HI, fig. 7;) at other times are disposed in long, straight 

 bands, parallel to each other, or divergent, palmated, or like a herring- 

 bone or vertebral column, (illustration j^o. TV, fig. 8,) their greater axis 

 oriented according to the sailing of the cloud and the direction of the wind 

 at that altitude, which soon makes itself felt at the surface of the earth. 

 When it forms two or more systems of straight, parallel bands, by an 

 effect of perspective they appear to diverge from their point of depart- 

 ure at the horizon, and to converge toward the point of the horizon op- 

 posite, as do the rays of the rising and setting sun. 



The cirrus is always white — sometimes brilliant, sometimes pearly- 

 dull. The earliest and latest reflections of the solar rays upon these 

 clouds color them with a delicate rosy tint, more or less intense, accords 

 iug to their density. Their movement is exceedingly slow, and their 

 altitude is not less than 10,000 yards, (more than six and a quarter 

 miles.) These clouds are the highest, apparently, slowest, most rarified, 

 most variable in their forms, and the most extended. The appearance 

 or disappearance of cirrus i3roclaims the end or the commencement of 

 good weather. The barometer sinks and then rises, all the accompany- 

 ing meteorological iflienomeua undergoing a similar change. We quote 

 from Howard: 



They are first iudicatcd by a few threads penciled, as it were, on the sky. These in- 

 crease in length, and new ones are iu tlic mean time added to them. Often the first- 

 formed threads serv.e as stems to support numerous branches, which in thein.turn give 



