June 18, 1920] 



SCIENCE 



607 



way from the mid-point (as measured from the 

 nucleus). If we take the radius Tector at the 

 mid-point to be unity then the radius at the 

 end of the arc is 1.138. The angular velocity 

 of the electron at the mid-point of the path is 

 such that if it continued with this velocity it 

 would travel through 105° 23' during the time 

 that it actually takes to move to the end of 

 its orbit (i. e., through 77° 58'). 



By imposing the quantum condition that 

 the angular momentum of each electron at 

 the mid-point of its path shall be h/2'^, it 

 becomes possible to calculate the radius vector 

 and the velocity in absolute units. The 

 radius vector for the electron at its mid- 

 point is 0.2534 X 10"^ cm. which is 0.8359 of 

 the radius of the orbit of Bohr's model 

 (0.3031X10"^ cm.). Even at the end of the 

 orbit the radius (0.2882X10"* cm.) is less 

 than that of the Bohr model. The angular 

 velocity at the mid-point is 1.431 times that 

 of electrons of the Bohr atom. The num- 

 ber of complete oscillations per second is 

 24.63X101=, which is 1.222 times as great 

 as the nrnnber of revolutions in the Bohr 

 atom (20.16 XIO^^ per second). The total 

 energy (kinetic plus potential) of the oscilla- 

 ting atom is 0.9615 of that of the Bohr atom. 

 The ionizing potential of helium according 

 to the new model should be 25.59 volts which 

 agrees with Franck and Knipping's experi- 

 mental determination within the limits of 

 error given by them, but differs from the 28.8 

 volts given by Bohr's theory by nearly ten 

 times the experimental error. 



The oscUlating model is thus not only 

 satisfactory from a chemical point of view 

 but is in quantitative agreement with the 

 properties of helium. The fact that there 

 can be no corresponding structure with three 

 electrons is in accord with the fact that 

 lithium (which has three electrons) is an ele- 

 ment having totally different properties from 

 helium. 



The calculation for the hydrogen molecule 

 involves greater difficulties. Bohr's model 

 with the two electrons moving in a single 

 circular orbit gives a heat of dissociation 

 of about 63,000 calories, whereas experiment 



gives about 90,000. The calculations for 

 helium have shown that the radius of the 

 oscillating atom is considerably smaller than 

 that of the Bohr atom, so that the force of 

 attraction between the electrons and the 

 nucleus is much (20 per cent, or more) 

 greater. In the hydrogen molecule this in- 

 creased force may result in drawing the two 

 nuclei closer together thus increasing the 

 stability of the molecule. Calculations of the 

 orbits of the electrons in the hydrogen mole- 

 cule are in progress. 



The final residts with a description of the 

 methods of calculation will be published prob- 

 ably in the Physical Review and the Journal 

 of the American Chemical Society. 



Irving Langmuie 

 Eeseakch Laboeatoet op the 



GENEEAIi ELECTEIC COMPANT, 



: Schenectady, N. Y., 



June 5, 1920 



ALFRED WERNERi 



Alfred Werner, professor of chemistry in 

 the University of Zurich, died on ITovember 

 15, 1919, at Zurich, Switzerland. 



Professor Werner was elected an honorary 

 member of the Ajnerican Chemical Society at 

 the general meeting held in ISTew Orleans, La., 

 April 1, 1915. It is now desired to leave upon 

 the permanent records of this society a tribute 

 to his genius and indomitable energy, and to 

 the wealth of the contributions which he 

 made to our science. 



Born at Mulhausen in Alsace on December 

 12, 1866, he was educated at the technical 

 schools of Mulhausen, Karlsruhe, and Zurich. 

 Later he studied with Berthelot at Paris. 



His first published work of note was upon 

 the stereoisomerism of organic compoxmds 

 containing nitrogen. Applying these theories 

 to the unclassified mass of complex inorganic 

 ammonia compounds, he realized the inade- 

 quacy of accepted ideas of valence to explain 

 their constitution. Largely from a study of 

 isomers among these complexes, whose eonsti- 



1 Tribute prepared by a committee of the Aineri- 

 can Chemical Society consisting of C. H. Herty, 

 H. L. Wells and Arthur B. Lamb. 



