B. TERRESTRIAL PHYSICS AND METEOROLOGY. io7 



of the wind. In the southern hemisphere, the bearing of the 

 centre is nearly eight points to the left of the direction of the 

 Avind. Again, in managing the vessel when you find your- 

 self in the right-hand semicircle, heave to on the starboard 

 tack. If in the left-hand semicircle, heave to on the port 

 tack. This is true in both hemispheres. By following this 

 latter rule, it will be seen that a ship laying to in the right- 

 hand semicircle in the northern hemisphere will be on the 

 starboard tack, and heading oft" from the centre, and in the 

 left-hand semicircle will be on the port tack, and heading to- 

 ward the centre; also, in the southern hemisphere, a ship lay- 

 ino- to in the rio-ht-hand semicircle will be on the starboard 

 tack, but heading toward the centre, and when in the left- 

 hand semicircle will be on the port tack, but heading off 

 from the centre. Japan Weekly Mail^ June^ 1873. 



CYCLONES AND AVAT:ER-SP0UTS. 



A work published during the past year by Dr. Reye, of the 

 University of Strasburg, on the above subject, has attract- 

 ed, deservedly, very much attention and received very high 

 encomiums. This gentleman has treated the subject, both 

 by an inductive process of reasoning, and also, to a certain ex- 

 tent, has elucidated the more obscure phenomena by a math- 

 ematical treatment of the problems relating to the deposition 

 of water from atmospheric vapor. Especially interesting is 

 liis study of the storms in the sun's atmosphere, to which he 

 devotes a chapter based upon the spectroscopic observations 

 of solar protuberances. In great part, Reye's work is a re- 

 view of what has been done by many previous meteorologists 

 in this field of study. He, however, himself merits the thanks 

 of his brother scientists in that he has, with scientific accuracy, 

 co-ordinated the various facts. The cause of the spiral move- 

 ment, which is proved to exist in the smaller tornadoes as 

 Avell as in the most extensive storms, is attributed by Reye to 

 the heat, which causes certain portions of the air to expand 

 and to rise, and allows other portions of the neighboring at- 

 mosphere to flow forward to fill up the space thus vacated; 

 but since this flow can not take place uniformly from all 

 sides, there begins often from the very commencement an ec- 

 centric flow and a feeble spiral movement of the rising air. 

 The air flowing inward, always with increasing accuracy, fol- 



