428 



SCIENCE. 



[N. S. Vol. XIX. No. 480. 



of root hairs. — J. W. T. Duvel records the 

 germination of seeds buried in soil at least 

 three and a half years, the seedlings obtained 

 being 128 in number and representing seven 

 genera and nine species. — Conway MacMillan 

 describes cumaphytism in Alaria, showing how 

 strongly the Alaria-type of body may become 

 modified by existence in the surf. 



SOCIETIES AND ACADEMIES. 

 PHILOSOPHICAL SOCIETY OF WASHINGTON. 



The 579th meeting was held January 30, 

 1904. 



Mr. 0. H. Tittmann, superintendent of the 

 Coast and Geodetic Survey, gave a brief ac- 

 count of the meeting of the International 

 Geodetic Association during the past summer, 

 at Copenhagen. The most important ques- 

 tions considered during the nine days' meet- 

 ing were longitude, gravity on land and sea, 

 and variation of latitude. 



Mr. L. A. Fischer, of the Bureau of Stand- 

 ards, read a paper on ' The International 

 Bureau of Weights and Measures,' which was 

 established in accordance with an agreement 

 signed by seventeen of the principal nations 

 of the world, including the United States, at 

 Paris, in 1875. A description was given of 

 the laboratory and other buildings, situated 

 on neutral territory in the Park of St. Cloud, 

 at Sevres, near Paris. An account of the 

 principal work of the bureau was given. This 

 included the comparison of the various na- 

 tional prototypes of the kilogram and meter 

 with one another and with the international 

 kilogram and meter, at present deposited in an 

 underground vault at the International 

 Bureau. The investigation of nickel-steel 

 alloys, the determination of the volume of the 

 kilogram of water, and the establishment of 

 the present standard hydrogen temperature 

 scale were also mentioned. The paper closed 

 with a brief account of the recent comparison 

 of the IT. S. Prototype Meter No. 27 with 

 the two standards of the International 

 Bureau. Only preliminary results of this 

 comparison were given, the final results be- 

 ing deferred until further comparisons have 

 been made between No. 27 and the two other 



copies of the International Meter in possession 

 of the Bureau of Standards. 



Mr. James Page, of the Hydrographic Office, 

 then presented the modern view of ' ocean 

 currents.' 



Two independent circulations are involved 

 in the movement of the waters of the sea: 

 (1) The vertical, sustained by differences of 

 temperature; (2) the horizontal, having its 

 source in the energy supplied by the wind. 

 The phenomena ordinarily described as ocean 

 currents belong wholly to the latter. These 

 currents have their origin in the impulse given 

 the layer of water immediately at the sur- 

 face by the wind. This impulse, by virtue 

 of internal friction, is communicated down- 

 ward, but with extreme slowness; the rate of 

 propagation being expressed by the formula 



V~t = 1736 • a; ■ ^ 

 n 



in which v^ is the velocity at the surface, and 

 t the interval (in seconds) required to com- 

 municate a velocity v„/n to a layer at a depth 

 of X meters. Immediately at and near the 

 surface the currents will thus be quite as 

 variable as the winds themselves. The truth 

 of this was shown by a comparison of the ob- 

 served frequency of winds from the several 

 quadrants with the observed frequency of 

 currents towards the opposite quadrants for 

 various portions of the sea. For the area 

 in the North Atlantic Ocean bounded by the 

 parallels 40°-45° N., and the meridians 30°- 

 35° W. the percentages were as follows: 



Winds. . . .N. E. 16, S. E. 20, S. W. 36., N. W. 28. 

 Currents. . S. W. 20, N. W. 18, N. E. 31, S. E. 31. 



At some little distance below the surface 

 these irregularities disappear, in consequence 

 of the sluggishness with which the impulse 

 given by the wind is transmitted downward. 

 Here the changes of the wind, as they occur 

 from day to day, are no longer felt; and the 

 waters probably move in a fixed direction and 

 with a constant velocity, namely, that which 

 the above formula would give them if there 

 prevailed continuously at the surface a wind 

 having the force and direction of the resultant 

 of the actual winds. 



At the 580th meeting, held February 13, 



