118 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ton, Mass., as given for each civil day in the Coast Survey 

 Tide-table for the Atlantic Coast. A discussion now being 

 made by Professor Mitchell of the whole tidal phenomena of 

 the Gulf of Maine will be of great interest, some hitherto un- 

 recognized laws of tidal movement having been developed. 



TIDES AND WAVES. 



Of the tidal observations made by the English Arctic Ex- 

 pedition of 1876, the preliminary report has been published 

 in Captain Nares's narrative. 



Professor Haimhton announces as the first result of the 

 tidal observations made bv the late British Polar Expedition 

 the complete confirmation of the result obtained by Dr. Bes- 

 sels on Hall's expedition i. e., the meeting of two tidal waves 

 from north and south in Smith Sound and confirming the 

 idea that Greenland is an island. 



An important paper on the Tides of the Southern Hemi- 

 sphere and the Mediterranean, by Captain Evans and Sir 

 William Thomson, was read before the Dublin meeting of 

 the British Association, and an abstract of it is printed in 

 Nature. 



A self-acting tide-computing machine has, according to Nat- 

 ure, been designed by Mr. E. Roberts, of the Nautical Alma- 

 nac office, and is being constructed for the India Office. 



The great ocean wave due to the Iquique earthquake of 

 May 9 has been considered in a memoir, by Geinitz, in the 

 December (1877) number of Petermann's Mittheilungen. 



The accurate self-reGjisterino; " limnimeter " on Lake Le- 

 man has afforded Forel the demonstration of the existence 

 of temporary rhythmic changes in the level surface of the 

 whole lake, due to a bodily vibration of the whole mass of 

 water. He has now traced these vibrations up to their pri- 

 mary origin, which is occasionally, perhaps, to be found in an 

 earthquake shock, but more usually in sudden changes of at- 

 mospheric pressure at some part of the lake. He finds that 

 the formula for the vibration of water in a basin, given by 

 Merian, at Basle, in 1828, and its simplification given by 

 William Thomson, apply well to the seiches of Lake Gene- 

 va. Similar oscillations are reported by Jansen to be record- 

 ed upon the self-recording tide-gauge (meregraph) at Brest. 



Forel also has proposed a new theory of the variations in 



