76 



SCIENCE. 



[N. S. Vol. XXII. No. 551. 



In studying the action of water on rock 

 powders, the principles of electrolysis and 

 electrical endosmosis were resorted to, since 

 on simple extraction and filtration the in- 

 soluble colloid or 'pectoid' decomposition 

 products retain the alkalis. These investi- 

 gations are as yet unfinished, but it is 

 hoped by this means to study the actual 

 kaolinization of the feldspars in the labora- 

 tory. It is also hoped that the determina- 

 tion of the endosmotic constant, according 

 to Wiedermann 's formula, of different rock 

 powders will furnish a means of accurately 

 ascertaining the relative rate of decom- 

 position under the action of water. 



Some Observations on the Deposition of 

 Alloys from Mixed Solutions: C. B. 

 . Jacobs. 



In studying the simultaneous deposition 

 of two metals from a mixed solution of 

 their salts, the author found that the diffi- 

 culty of preventing the solution from at- 

 tacking and dissolving the more electro- 

 positive metal after deposition could be 

 overcome by the use of two anodes, one of 

 the electropositive metal and one of the 

 electronegative metal, connected to separate 

 generators running at different voltages, the 

 current returning through the cathode in 

 the bath by a common third leg to the gen- 

 erators. Alloys of zinc and nickel and of 

 zinc and copper were deposited in this 

 manner from neutral sulphate solutions. 

 With cyanide solutions of copper and zinc 

 a great variety of brass work was plated 

 from the same bath by changing the volt- 

 age on either anode, so as to deposit a 

 brass running high in copper and low in 

 zinc, or vice versa. 



Some Properties of the Metal- Ammoniums : 



C. A. Kraus. 



A study was made of the conductivity 

 and of the conductivity temperature coeffi- 

 cient of the metal-ammonium solutions, 

 from which it develops that the properties 



of these solutions are very different from 

 those of salt solutions in ammonia. Migra- 

 tion experiments were carried out which 

 show that a metal-ammonium solution may 

 behave like a metallic electrode. The proc- 

 ess of solution of a metal in ammonia is 

 not accompanied by electromotive forces. 

 The bearing of the optical properties on 

 the problem of the metal-ammoniums was 

 briefly pointed out. 



A Determination of the Coefficient of Ex- 

 pansion of Oxygen: Edward W, Morley 

 and Dayton C. Miller. 

 The method employed is a differential 

 one, in which two globes, both filled with 

 hydrogen, are connected to a differential 

 manometer, and the difference of pressure 

 of the gas in the two globes is measured at 

 zero and at one hundred degrees, the ma- 

 nometer being at a constant temperature. 

 Oxygen is then put in one of the globes, 

 and by means of the differential manom- 

 eter the expansion of the oxygen is com- 

 pared with that of the hydrogen which 

 previously filled the same globe. A value 

 obtained some time ago w^s not final, since 

 the glass of the globes would not endure 

 repeated exposure to steam. 



"With the present apparatus, a value has 

 been secured which is not subject to much 

 uncertainty. The coefficient of expansion 

 of "hydrogen as determined by the Bureau 

 International des Poids et Mesures being 

 0.00366,254, the value of the authors for 

 the coefficient of expansion of oxygen is 

 0.00367,00. 



Tlie Isolation and Properties of Some 

 Electro-Positive Radicals: C. A. Kraus. 

 (By title.) 



On the SoluMlity and Specific Rotatory 

 Poicer of Carbohydrates and Various Or- 

 ganic Acids and Bases in Pyridine and 

 Other Solvents: J. G. Holty. 

 Pyridine, the solvent chiefly used in the 



