their Pro^mtionf Suspensiqn, and Destruction, 7 



ances, and compare them with the changes that ensue In 

 the atmosphere. A number of observations, made hitherto 

 chiefly in one place, and without system or aid from con- 

 current ones in other places, have furnished the preceding 

 data (see vol. xvi. p. 100), which may serve as hints for fu- 

 ture investigation. 



At present we can only conjecture that the local detached 

 cirri which ramify in all directions are collecting particles 

 of water from the surrounding space, and at the same time 

 equalizing their own electricity with that of the air or va- 

 pour. 



That when numerous oblique short tufts appear, they are 

 conducting between the air above and that below them. 



That a decided direction of the extremities of pendent 

 or erected cirri from the mass they join towards any quar- 

 ter, is occasioned by the different electricity of a current of 

 air which is pressing upon the space they are contained in 

 from thence. This is the most important point to attend 

 to, as these tails sometimes veer half round the compass 

 in the course of a few hours ; and many observations have 

 confirmed the fact that they point towards the coming wind, 

 and are larger and lower as this is about to be stronger. 



Lastly, that cirri in parallel lines stretching from horizon 

 to horizon denote a communication of electricity carried 

 on through these clouds over the place of observation ; the 

 two predisposing masses of atmosphere being very distant, 

 and the intermediate lower atmosphere not in a state to 

 conduct it. It is at least a circumstance well deserving in- 

 quiry, by what means the clouds in stormy seasons become 

 arranged in these elevated parallel bars, which must be at 

 least 60 miles long, and are probably much more, considering 

 their elevation, and that both extremities are often invisible. 



Of the Nature of the intermediate Modifications, 

 The conversion of the cirrus into the cirro-cumulus is a 

 phaenomenon which at some seasons may be daily traced, 

 and serves to confirm the opinion that there exists some- 

 what of the same difference between the cumulus and the 

 cirrus, as between a charged and a transmitting or an in- 

 fluenced conductor among solid bodies. On this supposi- 

 tion, the orbicular arrangement of the particles ought to take 

 place as soon as the mass has ceased to conduct from par- 

 ticle to particle, or to be so acted on by a contiguous con- 

 ductor as to have n plus and minus state within itsdf at the 

 same time: and as this sort of communication in a cloud 

 may be as slow as in other imperfect conductors, the equi- 

 A 4 librium 



