NO. 17.] ATMOSPHERIC PRESSURE AROUND THE NORTH POLE. 571 



6. Report on the Scientific Results of the Voyage of H. M. S. Challenger 

 during the years 1873—76. Physics and Chemistry. Vol. II. Part V. 

 Report on atmospheric circulation. By Alexander Buchan, M. A., L. L. D. 

 London, 1889. 



7. Repartition de la pression atmospherique sur I'ocean Atlantique septen- 

 trional d'apres les observations de 1870 a 1889. Par G. Rung. Copen- 

 hague, 1894. 



Besides these printed publications, I have been able to utilise the observa- 

 tions made by Capt. Sverdrup's Fram-Expedition at Hayes Sound and Jones 

 Sound, in the years 1898 to 1902. 



The charts. Plates XI — XIII, give the pressure at sea-level and the stan- 

 dard gravity. 



As we have no means for reducing the barometer-observations of the 

 Fram to monthly normals, the position of the ship being too far from any 

 regular meteorological station with a long series of observations, I have been 

 obliged to use the Fram-observations with a certain freedom in drawing the 

 isobars, taking sometimes a kind of mean for 2 or 3 years, and making allowance 

 for the direction of the wind in accordance with the baric wind-law. Great 

 assistance in drawing the isobars in the interior arctic regions is given by 

 the observations from the continents and their shores, and from the islands 

 repeatedly visited by scientific expeditions. 



In all months we find the North Atlantic minimum of pressure more or 

 less developed. With the exception of June, in which month it lies over 

 Southern Greenland, we find it in Davis Strait, southwest or west of Iceland, 

 over the Norwegian Sea, and in the colder months farther eastwards in the 

 north of Russia and Siberia. 



On the other side we find the Pacific minimum south of Bering Strait 

 and in Alaska. 



The divide between these two regions of lower pressure extends from 

 North America generally to Eastern Siberia. Its existence and position has 

 already been pointed out by Prof. Supan, who has given it the name of 

 "Die arktische Windscheide" (The arctic wind-divide).^ 



Petermanns Mitteilungen 1891, p. 191. 



