On Sal Nitrum and Nitro- Aerial Spirit 125 



CHAPTER XI 



OF THE AERIAL VORTEX, OR ASCENT OF SEA- 

 WATER. Anglice: A SPOUT 



Seeing that we have treated of the elastic power of air 

 and of its motion, let me be permitted to submit here 

 some observations regarding the wonderful pheno- 

 menon familiar to sailors, which is in English called 

 a Spout ; that, namely, in which a huge mass of water 

 rises up on high like a pillar, and besides a whirlpool 

 of water is carried aloft. For I think that that pheno- 

 menon is caused by a whirling movement of the air 

 and by a diminution of its elastic force and pressure. 

 For I cannot agree with those who maintain that an 

 ascent of water such as this, arises solely from the 

 circumgyration of the water, as though on being 

 driven into a circle, whether by winds rushing from 

 opposite points or in any other way, it were thrust 

 on high at the centre of its vortex. For it is scarcely 

 credible that from this cause water could be raised to 

 so great a height as in the aforementioned pheno- 

 menon, since there is nothing to hinder water raised 

 above the surface in that manner from soon flowing 

 over to the sides. But indeed it has been ascertained 

 by experiment that water, when made to rotate, rather 

 falls downwards at the middle of its vortex than 

 ascends in that way. 



But in order that the reason of the phenomenon 

 may be known, I have thought it desirable to present 

 a representation of it, as it was delineated by a clever 

 sailor who had much experience of these things, 

 in Plate VI., Fig. i. In this figure: 



