B. TERRESTRIAL PHYSICS AND METEOROLOGY. 73 



as high as 50. The Molucca Passage, however, is open to 

 the depth of 1200 fathoms, and the China Sea to that of 1500 

 fathoms. 12 A, Dec. 31, 1874, 174. 



INFLUENCE OF WINDS UPON THE TIDES. 



In the appendix to the recent volume of the report of the 

 United States Coast Survey, Mr. Ferrel presents a revision 

 of his discussion of the tides of Boston Harbor, in which, 

 among other matters, he investigates the effect of winds and 

 barometric pressure on the height of the tides. After com- 

 paring the actual observations with the ordinary formula for 

 computing the heights of the tides, certain residuals remain, 

 which may possibly be in part explained as due to the influ- 

 ence of the winds and the barometer. He shows that this 

 influence varies very much in different parts of the world. 

 Thus, at Boston, a rise of an inch in the barometer is followed 

 by a fall of seven and one-third inches of water. At Brest, 

 however, for the same change in pressure, the change in the 

 water is fourteen and one-ninth inches, and at Liverpool 

 eleven and one-tenth inches, while at London it is only seven 

 inches, being even less than the value obtained for Boston. 

 The direct effect of atmospheric pressure is probably to a 

 large extent inextricably complicated with the influence of 

 the winds. Mr. Ferrel suggests as an explanation that when 

 the barometer is rising we usually have clearing weather on 

 the New England coast, with westerly winds, which tend to 

 lower the sea level ; they consequently more than counteract 

 the direct effects of inertia and friction. When the barome- 

 ter is falling there are usually east winds, or, at least, an ab- 

 sence of west winds, and the sea level at this time is a little 

 above the mean level. Very strong winds change the sea 

 level in Boston Harbor a foot or more, ten such cases occur- 

 ring in the course of one year. Report of the XI. JS. Coast 

 Survey, 1871,94. 



THE CHALLENGER OBSERVATIONS ON THE DEEP-SEA BOTT03L 



Professor Huxley, in a recent lecture at the Royal Institu- 

 tion upon the work of the Challenger expedition and its 

 bearing upon geological problems, sums up the general re- 

 sults, in regard to the composition of the ocean bed, by show- 

 ing that from the researches of Sabine, Ross, Pennv, Ehren- 



D 



