258 On Water-Spouts. 



ing. This result is sufficiently remarkable to make us desirous 

 of possessing further observations of a similar nature ; but, as I 

 have already said, my notes contain no others ; and on referring 

 to the books in my possession, I have found no information on 

 this subject. 



Foi'matioji and PheJiomena of Water-Spouts. — In most ac- 

 counts it is stated that water-spouts are formed from above. Some 

 observers, however, expressly say, that they have seen them in 

 the act of being formed from below. Michaud, who in 1789, 

 observed some water-spouts in the harbor of Nice, laid much 

 stress on this commencement from the surface of the sea ; it will 

 appear, however, from what is to follow, that this only seems to 

 be the case, and proceeds from the circumstance that the whirl 

 of wind which forms it, so long at it is not impregnated with va- 

 por or drops of water is not visible. 



When a water-spout begins to be formed over the sea, there is 

 generally to be observed a circular portion of the surface of which 

 is uneven, and has a black appearance. Soon after, the water is 

 elevated in the form of a pillar, in which a violent internal move- 

 ment is observable, the height being several fathoms. It foams, 

 and produces drops of water above, which it scatters in great 

 quantity on all sides, so that it distinctly exhibits an ascending 

 and descending course, which moves in parabolic curves, like 

 spring water ascending in a slanting direction. The internal 

 movement has been compared to boiling, and it has been believ- 

 ed that this idea was confirmed by the mass of vapor and fog 

 which generally floats above the water-spout. De la Nnx, how- 

 ever, who, for forty years, lived in the Island Bourbon, where 

 water-spouts are extremely common, maintains that this vapor is 

 only apparent, and that it proceeds from the great number of 

 drops of water spurted about. He also says, that, in order to be 

 convinced of this, it is only necessary to see the phenomenon in 

 a proper light, it would, however, be to bold too assert that this is 

 always the case. It is not impossible that vapors may be formed 

 around the agitated water, if that water possessed a lower tem- 

 perature, than the air and thus cooled the moisture contained in 

 it. That this takes place, must not be assumed, until the circum- 

 stances observed shall give suflicient support to the idea. 



On land, the nature of the phenomenon does not easily allow 

 observers to see the beginning of the formation of the lowest 



