H 



VRB NATURAl- HISTORY «» CLnUSS. 



ere i^lso certain forms of it, more deep and dense than or-? 

 liinaiy, and arranged on a cuivfid base, which euter into the 

 peculiar features of thundtr-storra. 



U is usuully found to accord with a rising baroojeter. 



CH^^a stratus 



la4ieatior*3. 



Of the Cirro-stratus. 



This is a muUifonn cloud, and can only be detected iq 

 it8 various appearances by an attention to its distinctive cha- 

 racters. It is always an attenuated sheet, or patch, floating 

 00 tl)e air, in a position nearly or quite horizontal, As we 

 have compared the cirrus to dry fiax, we ijaay here consider 

 it as drenched in water, and having its spveadiijg fibres re?: 

 quced to a closer and recumbent form. Viewed over head, 

 it is remarkable for its uuiform hazy continuity, and in the 

 . horizon for its great appearance of density, the consequencp 

 of its being seen edgewise. In this situation, also, it aome- 

 titpes cuts the sun's pr mpop's disk across with a dark line j 

 pf vvhich Virgil, 



♦« J[He ubi nascentem maculis variaverit ortum 

 Conditus in nuberp, medioque retugerit orbe, 

 3uspecti tibi sint imbres; namque urget ab alto 

 ^rhpribusquej satisque uptus, pecorique sinister." 



Georgic, lib, i. 



Or should his rising orb distorted shine 



Through spots, or fast behind a cloud's dark line 



K^Mre eclipsed ; then let the swain prepare 



For rainy torrents: a tempestuous air, 



^wjft from the southern deep, cotnes fraught with ill. 



The corn and fruits to waste, the flocks to chill. 



The rirro-str^tus is the natural indication of depression of 

 temperature, wind, and rain. In order ro make a proper use 

 pf it in this respect, it is necessary to attend to the tirneof its 

 /ippearance, to its continuance, and its accompaniments. 

 This cloud sometimes alternates with the cirro-cumulqs, 

 either at different intervals of the day, or in the same sky, or 

 <?ven in the saiiu* straturtj, which may consequently be seer) 

 (tgccessiytly in each modiBcation, and at interva'e, partly in 

 ope, p^i't\y iu the other. In ihi^ case the prognostic is 



doubtful. 



