( 281 ) 



On the Cause of Storms. By Mr G. A. RowELL. Communi- 

 cated by the Author.* 



In the paper read before the Ashmolean Society in 1839, 

 explaining the hypothesis by which I endeavoured to shew 

 the cause of evaporation, the suspension of clouds, &c., 1 at- 

 tempted to explain the cause of barometrical fluctuation and 

 atrial currents by the same hypothesis. 



The following is intended to shew, that the causes therein 

 assigned are sufficient to account for the variable winds and 

 storms in temperate climates and high latitudes ; the storms 

 of tropical regions, and the barometrical changes previous to 

 and during rains; and the probability that these phenomena 

 are caused by the precipitation of vapour, and the escape of 

 its electricity, in a much greater degree than by any change 

 of temperature in the atmosphere. That the action of the 

 sun and changes of temperature have great influence on the 

 atmosphere, is clearly shewn by the trade- winds, land and 

 sea breezes, &c. ; but these changes of temperature come on 

 steadily, and the heated air near the earth's surface is in 

 most cases driven gradually away by the colder and heavier 

 air ; but the vacuum or rarefaction caused by the precipita- 

 tion of rain, and the escape of its electricity, is often very 

 sudden and of great extent. According to the hypothesis,* 

 each particle of vapour is surrounded and buoyed up by its 

 coating of electricity, and each particle, together with its 

 coating of electricity, must occupy the space of an equal 

 weight of air ; therefore, as water is about 860 times heavier 

 than air at the level of the sea, every particle of water that 

 falls to the earth must have occupied 860 times the space 

 when suspended in the air ; and if, in a given time, 1 inch 

 of rain falls to the earth, it must, during that time, have 

 caused a vacuum or rarefaction in the space above to the 

 extent of 860 inches. The vacuum would, in fact, be greater 

 than this, for, as the density of the atmosphere decreases as 

 we recede from the earth, the vapour and its coating must 



* Lately read at a meeting of the Ashmolean Society, Oxford. 



t See Edinburgh New Philosophical Journal, vol. xxxviii., page 50. 



VOL. XL. NO. LXXX. — APRIL 1846. T 



