August 13, 1920] 



SCIENCE 



161 



per cent, in some cases, and shifted the minimum 

 to 10°. The authors find no evidence of a mini- 

 mum at 10° and that Estreicher 's results are about 

 65 per cent, too high and the recalculated ones 

 from 16 to 93 per cent, too high. 



WasMng in hard water in the presence of col- 

 loidal organic hydrosols: I. N. Kugelmass. 



Mineral ail-soap jellies as a foundation for 

 greases: Haekt N. Holmes. 



A photometric method for the study of colloids 

 and some applications to gelatine : S. E. Sheppaed 

 and Felix A. Elliott. 



Protoplasm and fuller's earth: G. H. A. Clowes. 



On colloidal absorption: the heterogeneous equi- 

 librium between colloids and ions: A. Mut- 

 scheller. The subject matter of the paper con- 

 sists of two parts; the first is experimental and 

 the second part is theoretical. The experimental 

 data given are those of changes caused by the 

 addition of zinc sulphate in increasing concentra- 

 tions to uniform solutions of gelatine. The ex- 

 periments performed are on (1) The migration ve- 

 locities of the ions; (2) the changes of the con- 

 centrations of the anions and cations; (3) the 

 velocity of motion of colloidal particles; (4) the 

 surface tension of the solutions; (5) the viscosity 

 of the solutions; (6) the swelling of gelatine. 

 The conclusions from these experiments are com- 

 pared with the process of ion adsorption by oil 

 drops as studied by Millikan and from the kinetic 

 theory and Einstein equation, adsorption equa- 

 tions of the type generally employed (H. Freund- 

 lieh & C. G. Schmidt) are derived. Various types 

 of adsorption and the general properties of col- 

 loids are reviewed as expressed by the equations 

 derived. (1) Swelling, (2) Hofmeister series, (3) 

 Valency rule, (4) the exponent, (5) the constant 

 and temperature coefiicient. 



A new form of hydrogen electrode apparatus: 

 Felix A. Elliott and S. F. Acree. 



Preliminary note on the use of the hydrogen 

 electrode for measuring the separate ionization con- 

 stants of polyaoids and bases; specifically tartaric 

 acid: Felix A. Elliott and S. F. Agree. 



The use of the hydrogen electrode in measuring 

 the ionization of acid salts: Felix A. Elliott and 

 S. F. Agree. 



A surface condensation error in certain measure- 

 ments of vapor pressure by the gas current satu- 

 ration method: Alan W. C. Menzies. The con- 

 densation of saturated water vapor on the surface 



of not too drastically steamed and washed glass- 

 wool, and also asbestos, was investigated under 

 conditions arranged to parallel as closely as pos- 

 sible those that have obtained in the case of many 

 published investigations in which the gas current 

 saturation method was employed. The results indi- 

 cate that certain annoying irregularities, which, 

 indeed, appear to have led some investigators to 

 abandon their work by this method, become com- 

 pletely explicable if the importance of this ne- 

 glected source of error is fully realized. 



The explanation of the Tammann-Schottky-Par- 

 tington anomaly: Alan W. C. Menzies. Tam- 

 mann found values, by the gas current saturation 

 method, for the dissociation pressure of salt hy- 

 drates from 2 to 5 per cent, higher than Frowein 

 had found by the tensimetrie method. Partington 

 by new measurements confirmed Tammann 's anom- 

 alous results, in harmony with Schottky's finding 

 that the initial readings in tensimetrie measure- 

 ments are higher than the equilibrium readings. 

 Explanations of the anomaly by Tammann, Nernst, 

 Campbell, Partington and Brereton Baker are dis- 

 cussed. Mindful of notorious precedent in the ease 

 of Charles II. and the Royal Society of London, 

 the author re-examined the facts experimentally, 

 and found that the real facts exhibit no anomaly. 



A differential thermometer: Alan W. C. 

 Menzies. 



The crystalligation of glass: a surface phenom- 

 enon. The repair of crystallized glass apparatus: 

 Albert F. O. Geemann. 



The separation of the element chlorine into 

 chlorine and meta-chlorine : William D. Habkins 

 and C. E. Broeker. 



A force, apparently due to mass, acting on an 

 electron, and the non-identity of isotopes in spectra 

 and other properties: William D. Harkins and 

 Lester Akonberg. 



A study of the system ammonia, magnesium, mer- 

 cury: Albert G. Loomis. 



The influence of pressure on the electrolytic con- 

 duction of aqueous solutions: Ealph E. Hall. 



A new form of portable standard cell: C. J. 



EOTTMANN. 



Hydrous oxides: II. Hydrous aluminum oxide: 

 Harry B. Weiser. 



Factors determining the degree of reversibility 

 of precipitation of colloidal hydrous oxides: 

 Harry B. Weiser. 



