442 Mr. T. Dobson on the Theory of Cyclones, Waterspouts, fyc. 



to Singapore. In Oct. 1841, 1 saw sice in action attached to one 

 cloud. In Aug. 1838 one passed over the harbour and town of 

 Singapore, dismasting one ship, sinking another, and carrying 

 off the corner of the roof of a house in its passage landward/' — 

 Journal of Indian Archipelago. 



" 1809. An immense waterspout broke over the harbour of 

 Honolulu. A few years before one broke on the north side of 

 the island (Oahu), washed away a number of houses, and drowned 

 several inhabitants." — Jarves's Hist, of Sandivich Islands. 



7. Cyclones begin in the immediate neighbourhood of active 

 volcanos. 



The Mauritius cyclones begin near Java; the West Indian 

 near the volcanic series of the Caribbean Islands ; those of the 

 Bay of Bengal near the volcanic islands on its eastern shores ; 

 the typhoons of the China sea near the Philippine Islands, &c. 



8. Within the tropics, cyclones move towards the west ; and in 

 middle latitudes, cyclones and waterspouts move towards the 

 N;E. in the northern hemisphere, and towards the S.E. in the 

 southern hemisphere. 



9. In the northern hemisphere, cyclones rotate in a horizontal 

 plane in the order N.W.S.E. ; and in the southern hemisphere, 

 in the order N.E.S.W. 



By applying the principles of electro-dynamics to the electricity 

 of the atmosphere, I shall endeavour to connect and explain the 

 preceding well-defined facts. The continuous observations of 

 Quetelet on the electricity of the atmosphere from- 1844 to 1849 

 (Literary Journal, Feb. 1850), show that it is always positive, 

 and increases as the temperature diminishes. It therefore in- 

 creases rapidly with the height above the earth's surface. We 

 may consequently regard the upper and colder regions of the 

 atmosphere as an immense reservoir of electric fluid enveloping 

 the earth, which is insulated by the intermediate spherical shell 

 formed by the lower and denser atmosphere. Now, whenever a 

 vertical Column of this atmosphere is suddenly displaced, the 

 surrounding aqueous vapour will be immediately condensed and 

 aggregated, and the cold rarefied air and moisture of the column 

 will form a vertical conductor for the descent of the electric fluid. 

 This descent will take place down a spiral, gyrating in the order 

 N.W.S.E. in the northern hemisphere, since the electric current 

 is under the same influence as that of the south pole of a mag- 

 net; and in the order N.E.S.W. in the southern hemisphere. 

 The air exterior to the conducting cylinder will partake of the 

 violent revolving motion, and a tornado or cyclone will be pro- 

 duced. The facts marked 9 are thus accounted for, as well as 

 the numerous circumstances indicative of intense electrical action, 



