with the Cofidensation of Vapour. 165 



Ixvii and Ixviii), that the resolution of this haze into the two 

 diverse niodifications (taking these, of course, as types of two 

 distinct classes of clouds), cirrus and cirrostratus^ depends 

 entirely on the electric state of the circumambient air. If the 

 equilibrium between the two masses of atmosphere, either su- 

 perposed or on the same level and at a great distance from 

 each other, is disturbed, the particles of water separated by 

 condensation immediately partake (as suggested) of the nature 

 oi conductors, and are then drawn out into fine lines or pencils 

 of condensed vapour, which transmit the electric force from 

 one portion of the atmosphere lo the other, until in some cases 

 the equilibrium is restored. Thus cirrus is formed. On the 

 other hand, if there is not such a disturbance of the electric 

 state of the atmosphere as here contemplated, but the charged 

 particles of water gradually subside so as ultimately to form, 

 from the accumulated haze, a thin extended sheet of cloud, 

 seen through which the heavenly bodies appear with increasing 

 dimness, the larger luminaries being not unfrequently sur- 

 rounded by well-defined halos, then the cirrostratus is formed. 

 In the former instance, the production of cirrus, while the 

 electric force is in process of transmission from one portion of 

 atmosphere to another, rain is not produced. When the equi- 

 librium is restored, and the fine lines of cirri cease to transmit 

 the electric force, the small orbicular masses of cirrocumulus 

 are produced ; and it may be that not only each particle may 

 retain its charge and sustain the character of an insulated 

 conductor, but the congeries of particles of water forming the 

 orbicular mass itself may possess such a character ; the mass, 

 as in the case of the cumulus, being an insulated conductor, 

 possessing such an amount of electric tension as is necessary 

 to preserve its independence among the other orbicular masses 

 forming the entire cloud ; each orbicular mass being consi- 

 dered as a component part thereof, just as each particle of 

 water is a component part of a cumulus. According as these 

 congeries of clouds may exist in dri/ or moist air, so evapora- 

 tion or condensation may take place on their surfaces. In 

 dry air they would gradually disappear; in moist air they 

 would not only augment in size, but their electric tension might 

 be so modified as to produce electric attraction, by which they 

 might pass into the modification of cirrostratus. 



In the foregoing remarks we have contemplated the passage 

 of the condensed vapour in the higher and middle regions of 

 the atmosphere, through the successive stages of cirrus and 

 cirrocumulus to cirrostratus. Still keeping in mind the 

 essential character of cirrus, and viewing its progress without 

 a restoration of the equilibrium, we may inquire into the result 



