Scientific InieUigence. — Hydrology. 425 



importance of thermonietric soundings to the west and east of 

 Cape St Vincent, will be apparent. Hence it appeared desirable 

 that the Academy should recommend this series of observations 

 to the Minister of Marine, and that a vessel should make a 

 hydrographical survey of the coasts of Morocco, whose com- 

 mander, M. Berard, is already occupied in ascertaining the 

 temperature of these seas at all depths, and with a degree of 

 success which the scientific world will fully appreciate. Never 

 did a more favourable occasion occur for the solution of the 

 great problem of terrestrial physics whose elements we have 

 now dwelt upon. — Arago. 



8. Water- Spouts. — The connection of water-spouts with elec- 

 tro-magnetism, a favourite subject with some German natural- 

 ists, has been brought forward by Colonel Reid in his memoir 

 on storms, read before the British Association, and we hope it 

 will not be lost sight of. The double cones in water-spouts, 

 one pointing upwards from the sea, the other downwards from 

 the clouds, are interesting features in the phenomenon ; these 

 ought to be more particularly examined, and we should also 

 ascertain whether the cloud above and the sea below revolve 

 in the same direction with each other. We also suggest to 

 those who may have an opportunity, to examine whether the 

 rain which the spout projects in all directions is salt or fresh. 



9. Hpt-Springs. — If we admit, with some naturalists of our 

 time, that hot-springs borrow their high temperature from the 

 terrestrial strata which lie deep below them, many of these springs 

 may then throw no trifling light upon the ancient thermome- 

 tric state of the globe. An example, one of the most favourable 

 that can be adduced, will exhibit the alliance of the two phe- 

 nomena very distinctly. 



In the year 1 785, M. Desfontaines discovered, at some dis- 

 tance from Bona, in Africa, a hot-spring whose temperature 

 was at 96° 3' Cent. This spring was known to the ancients ; 

 for the ruins of baths, in the immediate neighbourhood, leave 

 no doubt upon that point. This circumstance, combined ^vith 

 the temperature 96° 3' Cent., leads, I conceive, to the conse- 

 quence that during 2000 years, the temperature of the ground, 

 in Africa, has not varied 4*> Cent. For, let us admit for a 

 moment, that during the 2000 years it had diminished 4« Cent. 



