836 



SCIENCE 



[N. S. Vol. XXXIX. No. 1014 



and fruits. Others believe that in its present float- 

 ing form the gulf -weed is a distinct species which 

 has lost the power of fruiting and increases only 

 by offshoots. In recent years the species of Sar- 

 gassum growing in different parts of the West 

 Indies have been more carefully studied and a 

 comparison with the floating gulf -weed shows that 

 mixed with the latter are found in small quantity 

 fragments of at least two species known to grow 

 in the West Indies. In only one instance has 

 there been found mixed with the gulf-weed a sea- 

 weed which must have come not from the Ameri- 

 can coastj but from Africa or southern Europe. 



In spite of the fact that most recent writers 

 consider the gulf -weed as a distinct species, there 

 is reason to think that it is really derived from 

 some Sargassum growing in the West Indies, 

 fragments of which are carried by the Gulf 

 Stream to the Sargasso Sea. There are, however, 

 still many doubtful points to be settled. 



THURSDAY EVENING, APRIL 23 



Meeting of the Officers mid Council 

 At 8:30 O'clock 



FRIDAT, APRIL 24 



Executive Session — 9:30 o'clocTc 

 Proceeding of the oflScers and council sub- 

 mitted. 



Morning Session — 9:35 o'clooh 

 Albert A. Michelson, Ph.D., Bc.D., LL.D., 

 F.R.S., Vice-president, in the chair. 

 Fhase Changes Produced hy High Pressures: 

 Percy W. Bbidgman. (Introduced by Pro- 

 fessor Goodspeed.) 



The packing and the form of apparatus were 

 described with which it has been possible to reach 

 high pressures. These pressures have been pushed 

 as high as 30,000 or 40,000 kgm. per sq. cm., or 

 15 or 20 times as high as that in modern ar- 

 tillery. The methods were then described by 

 which it is possible to tell when a liquid is frozen 

 to a solid or one solid changed into another by the 

 application of pressure. One of the problems of 

 particular interest is as to the character of the 

 melting curve. There have been theories pro- 

 posed, but hitherto sufficient pressure has not 

 been obtainable to submit these theories to ex- 

 perimental test. Examination of the melting of a 

 number of liquids over a wide pressure range has 

 shown that the theories hitherto proposed do not 

 hold at high pressures. The fact seems to be that 

 as far as we can judge the melting curve con- 



tinues to rise indefinitely, so that a liquid may be 

 frozen by the application of sufficient pressure, 

 no matter how high the temperature. A number 

 of results are also obtained for the reversible 

 transition from one crystalline form to another. 

 Several new solid forms have been obtained ; of par- 

 ticular interest are the new forms of ice, which 

 are denser than water. In addition to these 

 changes, which are completely reversible, one ex- 

 ample has been found of an irreversible reaction 

 produced by high pressure; yellow phosphorus may 

 be changed by 12,000 kgm. and 200° to a modifi- 

 cation in appearance like graphite, which is 15 

 per cent, more dense than the densest red phos- 

 phorus. 



The Influence of Atmospheric Pressure on the 

 Forced Convection of Heat from Thin Electric 

 Conducting Wires: Arthur E. Kennelly. 



Some New Tests of Quantum Theory and a Direct 

 Determination of "h": Robert Andrews 

 MiLLiKAN. (Introduced by Professor Good- 

 speed.) 



It has been known for 25 years that when light 

 of sufficiently short wave-length, i. e., of suffi- 

 ciently high frequency, falls upon a metal, it has 

 the power of ejecting electrons from that metal. 



It has been known for seven years that the 

 kinetic energy possessed by the electrons thus 

 ejected is larger the higher the frequency of the 

 light which ejects them. In other words, blue 

 light throws out electrons with greater speed than 

 does red light. 



Whether or not the energy of ejection is di- 

 rectly proportionate to frequency has been a mat- 

 ter of some uncertainty and of considerable dis- 

 pute up to the present time. 



The work herewith presented furnishes in the first 

 place the most conclusive proof which has yet been 

 found that there is exact proportionality between 

 the energy of the ejected electrons and the fre- 

 quency of the light which ejects them. 



The second and most important contribution 

 which it makes is the proof, given here for the 

 first time, that the factor of proportionality be- 

 tween the energy of the ejected electrons and the 

 frequency of the incident light is exactly the same 

 quantity which has figured so largely in the re- 

 cent developments of theoretical physics, namely, 

 the fundamental constant which appears in 

 Planck's theory of the discontinuous or explosive 

 character of all radiant energy of the electro- 

 magnetic type. This constant is known as 

 Planck 's "h" and its value is directly deter- 



