PHYSICS OF THE GLOBE. 173 



barometer rises less in proportion as the angle is larger which 

 the direction of the lower clouds' movement makes with the 

 direction of the barometric gradient. 



Dr. W. Koppen, of the Deutsche See warte, calls attention to 

 the fact that Professor Erman,in 1853, in PoggendorfF's An* 

 nalen, vol. lxxxiii., proved that the direction of the wind Avas 

 inclined to the barometric gradient in accordance with the law 

 now frequently, but wholly erroneously, called Buys-Ballot's 

 law. Furthermore, he shows that Dr. Dippe published in 1860 

 a still more elaborate investigation into the relations between 

 isobars and winds, and determined the angular deviation, and 

 also the strength of the wind, in terms of the gradient. The 

 present writer has previously called attention to the fact 

 that Buys-Ballot's law, as enunciated by him, is simply a rule 

 for predicting the winds in Holland, and is not at all a general 

 physical law of storms. The inclination of the winds to the 

 isobars was elaborately worked up by James Henry Coffin, 

 and published in the Proceedings of the American Associa- 

 tion for the Advancement of Science, 1 853 ; while in the same 

 year Rev. Humphrey Lloyd deduced the angle between the 

 winds and the radius drawn to the centre of the system of 

 winds. The physical explanation of the laws of the winds is 

 due to Ferrel, whose first publications date 1856, although 

 lie had then for some years perceived and taught the cor- 

 rect views. 



An important memoir, by Hofimeyer, is published in the 

 Zeitschrift of the Austrian Meteorological Society for Octo- 

 ber, on the Distribution of Atmospheric Pressure over the 

 North Atlantic Ocean during the Winter, and its Influence on 

 the Climate of Europe. He prefaces his remarks by reference 

 to Buys-Ballot's law, and to the researches of Ley, Ferrel, 

 Mohn, Guldberg, Loomis, and Broun. As an improvement 

 on the charts of isobars published by Buchan and WoeikofF, 

 he gives tables and charts based upon a much larger num- 

 ber of observations, which, he thinks, must be recognized as 

 the most reliable that can be produced at present. 



According to this new chart, for January, the principal i 

 minimum for the North Atlantic is to the southwest, and 

 not to the northeast of Iceland; while a partial minimum 

 extends from this point towards the North Cape on the one 

 hand, and towards Davis Strait on the other hand. 



