54 Causes of Water Sponts. 



be destroyed ; from the statements that are given, these spouts are 

 sometimes broken, and instantly assume the aspect of a broken 

 column. This arises from an increased velocity in the superior cur- 

 rent, or in that of the inferior. 



The phenomenon of an ascending spout in action, may be imagin- 

 ed as a vast column of air composed of two cylinders, one contained 

 in the other, having a movement of rotation in the same direction, the 

 inside one being very small, rises, while the exterior, which is much 

 larger, descends. At the bottom of the column the exterior cylinder 

 folds itself towards the centre in grazing the sea, and forms the inte- 

 rior cylinder, like a bag turned in at the bottom ; the rapidity of the 

 movement of the cylinders is in inverse proportion to their mass, 

 and in direct proportion to the swiftness of the primitive whirl which 

 produces the phenomenon. 



When the whirl "is fully established, it lasts as long as the winds 

 which produced it in the clouds. It sustains itself — the air on the out- 

 side gives it no support, which explains the calm that exists at a short 

 distance from the spout. 



At the moment when, from the heights where it commenced, the 

 whirl of invisible air, folding continually upon itself, grazes the sur- 

 face of the sea ; and drives the water from the circumference to the 

 center, as the winds push the waves ; then, it bubbles up, divides, 

 and as it revolves, mixes itself with the air, forming a mixed spout of 

 water and air, the weight of which is greatly inferior to a similar co- 

 lumn of pure water. It must also be observed, that when the exterior 

 part of the whirl reaches the sea in a spiral direction, it strikes the 

 latter obliquely in pressing on the surface, which favors the adhesion 

 of the two fluids, and causes the center of the air subjected to its ope- 

 ration to rise in the form of a cone. The truth of these observations 

 is proved by the accounts given by different navigators. 



Dr. Mercer, saw at Antigua, three spouts; the water was violently 

 agitated in a circle of twenty rods, whence it was swept and carried 

 into the air, with great rapidity and tumult. 



It has been constantly remarked, that when the ascending spouts 

 rise as high as the clouds, their density augments rapidly ; they are 

 seen accumulating, and growing darker, until the phenomenon ends 

 in a tremendous fall of rain. This effect cannot be attributed to the 

 water alone which lises from the sea. An ascending spout cannot 

 take place from the sea to the clouds, without a corresponding de- 

 scending current, from the regions of air above the cloud, which 



