AND THE PREVAILING WINDS OVER THE GLOBE. 583 



no respect from what occurs on particular days on which the isobaric lines present 

 the same conditions of pressure. Mr Francts Galton first drew attention to this 

 peculiarity, under the name of Anticyclones, by which name he intended to convey 

 the idea that in cases of high pressure occurring over a limited area, the course of 

 the winds is exactly the reverse of what is seen to prevail in cyclones in which 

 the winds blow round and in upon a space of low pressure. 



The outflow of the air from a region of high pressure, and the inflow upon a 

 region of low pressure, appears to be reducible to a single principle, viz., the 

 principle of gravitation. Given as observed facts the differences of pressure, it 

 might almost be predicted, before calculating the averages, what the prevailing 

 winds are. Indeed, so predominating is the influence of gravitation that it may be 

 regarded as the sole force immediately concerned in determining the movements of 

 the atmosphere. If there be any other force or forces which set the winds in mo- 

 tion, their influence must be altogether insignificant as compared with gravitation. 



The effect of a mountain range interposed in the course of one of these great 

 atmospheric currents is interesting. Of this, the best example is furnished by the 

 mountain range of the Scandinavian peninsula, in its effect on the prevailing winds 

 in winter. It will be observed that this mountain range lies between the low 

 pressure about Iceland, and the high pressure in the interior of Asia. 



The following are the mean directions of the wind at different places in Norway 

 in January, deduced from Table II., to which are added the winds at other points, 

 courteously sent by Professor Mohn : — Christiania, N.E. ; Sandosund, N.N.E. ; 

 Lindesnes, N.E. ; Mandal, N.E. by E. ; Lister, E. ; Skudesnes, S.S.E. ; Udsire and 

 Bergen, S. ; Christiansund, S.S.E. ; Villa, S.E. ; Hammerfest, S.E. by S. ; and 

 Vardo, S.W. Thus at Christiania, Sandosund, and Lindesnes, which lie on the east 

 side of the south spur of the mountain range, the prevailing winds are N.E. or 

 N.N.E. ; at Mandal, at the extreme south point of Norway, the wind is N.E. by E., 

 and calms also largely prevail ; and at Lister, a little to the west, the wind is 

 E. ; along the whole west coast from Skudesnes to Hammerfest, near the North 

 Cape, winds are chiefly S., S.S.E., or S.E. ; while at Vardo, to the east of the north 

 spur of the mountain range, the prevailing winds are S.W. These directions are 

 very much the directions water should take in flowing past and round a rock 

 lying in the bed of the current ; the Scandinavian mountains being in this case 

 the obstacle which diverts the winds from what may called their normal course 

 in flowing towards and round the low pressure in the north of the Atlantic, 



On the other hand, in July it is seen from the Chart (Plate XXVI.) that the 

 lowest pressures occur in the interior of Asia, towards which there is an extensive 

 aerial current from W.S.W., W., and N.W. over Europe and Western Asia. Here 

 also the influence of the mountain system of Norway is very perceptible. The 

 following are the prevailing winds in July:— Christiansund, N.W. by N. ; Bergen, 

 N.; Skudesnes, N.W. ; Lindesnes, W. ; Mandal, W. by S.W.; Sandosund, S.W. ; 



VOL. XXV. PART II. 7 M 



