B. TERRESTRIAL PHYSICS AND METEOROLOGY. 55 



Wolf has found, from an examination of the chronicles of 

 Zurich, that in Switzerland the maximum of solar spots 

 agrees with dry and fruitful years ; while Gautier finds, from 

 a more extended series of observations, an exactly opposite 

 conclusion. It is quite possible, however, that both may be 

 true that, in reality, the result of greater solar energy might 

 produce in one region a greater desiccation, while in another 

 a greater precipitation followed. 



The correspondence between the fluctuations of the lakes 

 and the solar spots seems to be sufficiently close to open a 

 very interesting field of inquiry, and to show that a sun-spot 

 cycle actually exists in all branches of terrestrial meteorol- 

 ogy as well as in the temperatures, the latter question hav- 

 ing been definitively established by the researches of Kop- 

 pen 12 A, 1873, IX., 504. 



TIDES IX THE ARCTIC OCEAX. 



One of the most interesting results of the Polaris arctic 

 exploration has beeu the deduction based upon the constant 

 and careful tidal observations that w T ere made at Thank-God 

 Harbor. Dr. Bessels says that it was found that, for that 

 place, the co-tidal hour is about 16 hours 20 minutes. Rens- 

 selaer Harbor, being the northernmost station, has a co-tidal 

 hour of 18 hours 4 minutes. Consequently the tide comes from 

 the north. The rise and fall at spring tides amount to about 

 5 feet ; at neap tides, 2.3 feet. Most likely the Atlantic and 

 Pacific tidal waves meet somewhere in Smith's Sound, near 

 Cape Frazicr. 12 A, IX., 404. 



THE ACTION OF TIDES OX THE SEA-BOTTOM. 



Mr. Reade communicates to the Geological Society of Liv- 

 erpool tUe result of a series of novel investigations on the ac- 

 tion of tides on the sea-bottom. He shows that, at various 

 points in the St. George's and English channels, and in the 

 Irish sea, tidal currents exist capable of destructive erosive 

 action on the sea-bottom, and that the materials of the Irish 

 sea-bottom are principally composed of rearranged glacial 

 drift, either eroded oft* the bottom or oft' the coast by the sea 

 itself, or poured into it by the many rivers. These materials, 

 notwithstanding the oscillatory character of the tidal streams, 

 have in the main a slow progressive motion down the chan- 



