S36 HISTORY OF 



earth, and produce an instant inundation,* which 

 could not readily have happened had they been 

 caused by the gyration of a whirlwind only. In- 

 deed, every conjecture regarding these meteors 

 seems to me entirely unsatisfactory. They some- 

 times appear in the calmest weather at sea, of 

 which I have been an eye-witness ; and, there- 

 fore, these are not caused by a whirlwind. They 

 are always capped by a cloud ; and, therefore, 

 are not likely to proceed from fires at the bot- 

 tom. They change place ; and therefore suction 

 seems impracticable. In short, we still want 

 facts upon which to build a rational theory ; 

 and, instead of knowledge, we must be contented 

 with admiration. To be well acquainted with 

 the appearances of nature, even though we are 

 ignorant of their causes, often constitutes the 

 most useful wisdom. 



t[" Dr Franklin, in his Physical and Meteorolo- 

 gical Observations, supposes a water-spout and a 

 whirlwind to proceed from the same cause ; their 

 only difference being, that the latter passes over 

 the land, and the former over the water. A 

 fluid moving from all points horizontally towards 

 a centre, must at that centre either mount or des- 

 cend. If a hole be opened in the middle of the 

 bottom of a tub filled with water, the water will 

 flow from all sides to the centre, and there descend 

 in a whirl ; but air flowing on or near the sur- 

 face of land or water, from all sides towards a 

 centre, must at that centre ascend, because the 

 land or water will hinder its descent. 



Phil. Trans, vol. iv. p. 2. 108. f Encycl. Brit WATER-SPOUT. 



