chap, viii.] THE GULF-STREAM. 393 



Scottish Meteorological Society, Mr. Buchan, with 

 regard to the temperature of the sea on the coasts 

 of Scotland, 



5. Prom the publications of the Norwegian Insti- 

 tute on sea-temperatures between Norway, Scotland, 

 and Iceland. 



6. Prom the data furnished by the Danish Rear- 

 Ad miral Irminger on sea-temperature between Den- 

 mark and the Danish settlements in Greenland. 



7. Prom the observations made by Earl Dufferin 

 on board his yacht 'Poam' between Scotland, Ice- 

 land, Spitzbergen, and Norway. 



And finally, from the recent observations collected 

 by the English, Swedish, German, and Russian ex- 

 peditions to the arctic regions and towards the 

 North Pole. 



Dr. Petermann has devoted the special attention 

 of a great part of his life to the distribution of heat 

 on the surface of the ocean, and the accuracy and con- 

 scientiousness of his work in every detail are beyond 

 the shadow of- a doubt. Plate VII. is in the main 

 copied from his charts, with a few modifications and 

 additions derived from additional data. The remark- 

 able diversion of the isothermal lines from their 

 normal course is undoubtedly caused by surface ocean- 

 currents conveying warm tropical water towards the 

 polar regions. This is no matter of speculation, for 

 the current is in many places perceptible through 

 its effect on navigation, and the path of the warm 

 water may be traced by dipping the thermometer 

 into it and noting its temperature. 



In the North Atlantic every curve of equal tem- 

 perature, whether for the summer, for the winter, for 



