230 NINTH ANNUAL REPORT OF 



State; and, consequently, the nnass which they constitute must be dila- 

 ted proportion ably to the intensity of the charge. Moreover, a mass 

 so electrified must be repelled by the earth proportionably to the 

 charge, so that in this way a diminution of barometrical pressure and 

 atmospheric density may ensue. 



31. But, according to Dalton's observations, the temperature being 

 constant, the quantity of moisture in the air is as the space occupied 

 by it, since it is the capacity of the space, not that of the air, which 

 regulates the proportion of moisture associated with the latter. 



32. It follows that when by electrical repulsion the air is dilated it 

 will have an increase of its capacity for moisture, proportional to its 

 dilatation, and when the electricity causing the increase of capacity is 

 discharged the moisture must precipitate. 



33. And further, when two masses of air, oppositely electrified, 

 coalesce proportionably to the neutraUzation, moisture must be de- 

 posited. 



34. Such masses tnust acquire by a reaction with the earth, and an 

 ascensional tendency arising from repulsion between them and the ter- 

 restrial surface. Mr. Wise's observations respecting the influence of 

 the electric medium upon the gas within his balloon, by which it was 

 so attenuated as to create a surprising ascensional power, is altogether 

 confirmatory of my inferences. 



35. It appears that Mr. Wise was enabled to vary the direction of 

 his sailing by varying the altitude at which he floated. Hence, as 

 there are al^a3^s two currents during gales, it would be possible for an 

 aerial navigator to determine his course by his elevation, as Mr. Wise 

 appears to have done. In a northeastern gale he might first use one 

 current in order to go to a sufficient distance, and then use the other to 

 return. 



