5G ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



THE OCEAN. 

 DENSITY, ETC. 



Mohn contributes to Petermann's Mittheilungen a memoir 

 on the temperature of the Atlantic east of Greenland. He 

 shows that a belt of warm water extends northeastward to 

 beyond the North Cape. This belt moves eastward in sum- 

 mer and westward in winter. He also accurately defines 

 the limits of the bottom stratum of cold water at maximum 

 density, and shows how it is limited by the configuration 

 of the sea bottom. 



Schmidt, of Dorpat, has extended his memoir on the salin- 

 ity of natural waters to the ocean and salt seas, and in a 

 comprehensive table gives the results of all known observa- 

 tions. 



TIDES. 



The tidal observations made by the English Polar Ex- 

 pedition of 187G have been reduced by Professor Haughton, 

 and. in a preliminary account of his results read before the 

 British Association, he stated that the results obtained by 

 Dr. Bessels from the Polaris expedition were confirmed by 

 the English expedition, viz., that there was a junction of 

 two important tides in the largest portion of Smith's 

 Sound. A new type of tide had been found confirming Dr. 

 Bessels' reasoning to show that Greenland is an island. 



At the same meeting of the B. A. A. S., papers " On the 

 Tides of Port Louis and of Freemantle" were read by Sir 

 William Thomson, and " On Solutions of Laplace's Tidal 

 Equation for certain Special Types of Oscillation." 



^VAVES. 



Forel, of Morges, on the north shore of Lake Geneva, has 

 from the study of the self-recording tide-gauge of large 

 scale shown that the surface of the lake oscillates rhyth- 

 mically in fixed periods about two axes, i. e., the longest 

 and shortest diameters of the lake. The times of vibration 

 are respectively seventy and ten minutes. 



Numerous notices have appeared in the Monthly Weather 

 Review of remarkable fluctuations in the waters of our Great 

 Lakes. These, however, appear mostly to be due to earth- 

 quakes, and have as yet never been shown to have any such 



