B. TERRESTRIAL PHYSICS AND METEOROLOGY. 89 



portional to the extent of the period that precedes it. Siq>- 

 plemento alia Meteor ologia Italia, Home ^ 1875, 28. 



THE SIMULTANEOUS EXISTENCE OF DIFFERENT CUKEENTS 



OF AIR. 



The exact knowledge of the presence of several currents 

 of air in the atmosphere around us is of so great importance 

 to meteorology that we record here the observations made 

 by Chapelas in France. On the 30th of April, at noon, he 

 observed a clear sky with a feeble northeast wind. At two 

 o'clock P.M. a slight thread of cirrus was seen moving rap- 

 idly from the west-southwest or southwest, the surface wind 

 remaining still northeast. On the first of May both wind 

 and clouds moved from the southwest at ten o'clock A.M. ; 

 and at one thirty P.M. a strong storm, followed at night by 

 clouds and wind from the northwest. On the second of May 

 at seven P.M. there appeared a balloon driven by a wind 

 from the west-northwest to the northeast, Avhile at the sur- 

 face of the earth it was quite calm. The balloon descending 

 in the Luxembourg quickly, when it arrived at an altitude 

 of about one hundred and fifty feet met a current diamet- 

 rically opposed to that which it had experienced above, and 

 "svas carried by it toward the southeast. 6 ^,LXXX., 1176. 



ON THE LAWS OF CYCLONES. 



The distinguished astronomer, Faye, of Paris, having been 

 led from his study of solar spots to investigate the subject 

 of terrestrial storms, has developed numerous novel views, 

 which will be found fully noticed elsewhere, and has lately 

 applied these views to the study of the hurricane of Febru- 

 ary 25, 1860, in the Indian Ocean. In this hurricane some 

 forty vessels were destroyed, and their loss is attributed by 

 him in great part to implicit confidence of the navigators in 

 the law\s for avoiding the centres of hurricanes that have 

 hitherto been promulgated. It is well known that Mr. Mel- 

 drum, by studying this same storm, was led to certain modi- 

 fications of the ordinary hurricane laws, but Faye differs 

 widely from his conclusions. Similarly Captain Ansart pro- 

 posed to reject the circular theory of cyclones, and to sub- 

 stitute ellipses for the spirals of Mr. Meldrum. By referring 

 to the original observations, so far as they are available for 



