94 



SCIENCE 



[N. S. Vol. XLII. No. 1072 



taining possibly some water vapor, is orange 

 red. To now introduce the illuminating gas 

 open the valve for a moment, then close it. 

 The end C of the discharge tube is instantly 

 filled with a beautiful greenish-white color 

 characteristic of illuminating gas. This color 

 will diffuse slowly towards A, each color pal- 

 ing out, and after three or four minutes the 

 discharge throughout the tube will assume a 

 uniform grayish hue. The rate of diffusion 

 is surprisingly slow and of course depends 

 upon a number of factors, e. g., the gas pres- 

 sure in the tube, the pressure of the gas that 

 is admitted, the ionization within the tube 

 due to the discharge passing through the tube, 

 the amount of moisture present, etc. 



If now the gas connection at N be removed 

 and this stem opened to the air the pump and 

 connections may be freed of gas and the in- 

 verse experiment performed; namely, that of 

 introducing a small quantity of air. The re- 

 sulting orange red color and its diffusion 

 through the grayish hue of the illuminating 

 gas is even more striking than the first. 



The success of the experiment depends 

 largely upon the skill of the operator in prop- 

 erly proportioning the quantity of gas to be 

 introduced. It is a very simple experiment to 

 perform. 



Chas. T. Knipp 



Laboeatoey op Physics, 

 xjniveesity of illinois, 

 June 2, 1915 



TEE NEW ORLEANS MEETING OF THE 

 AMEBICAN CHEMICAL SOCIETY. Ill 



DIVISION OF PHYSICAL AND INORGANIC CHEMISTRY 



Gr. A. Hulett, chairnum 



E. C. "WellSj secretary 



E. E. Weaver: A Colorimetric Determination of 



Acetylene. 



A new colorimetrio method for the determina- 

 tion of very small amounts of acetylene in gas 

 mixtures depends upon the formation of a red col- 

 loidal solution of cuprous chloride containing gela- 

 tine and alcohol. Comparison is made with a so- 

 lution of a red dye or a piece of ruby glass. In 

 the gravimetric determination of acetylene it has 

 been found necessary to exclude air during the 

 filtration and washing of the precipitate. 



Geoe<3e "W. Morey: Tlie Ternary System KjO- 

 SiOMM from 300°-700°. (Lantern.) 



E. C. Franklin: Huhidium Ammonosodate and 

 Ammonopotassiate. 



E. S. McBride: Experiments on the Distillation of 



Liquid Air in a Magnetic Field. 



Preliminary experiments on distillation of liquid 

 air in a strong magnetic field indicate that there 

 is an improvement in the separation of oxygen 

 and nitrogen due to the influence of the magnetic 

 field. 



E. P. ScHOCH and Denton J. Beown: A Syste- 

 matic, Sapid, Electroanalytical Procedure for 

 tlie Separation and Determination of Silver, 

 Arsenic, Copper, Bismuth, Antimony, Tin, Lead 

 and Cadmium. 



In our earlier work, published elsewhere, we 

 have shown that copper, tin, lead, bismuth and 

 antimony can be determined accurately by electro- 

 deposition out of acidified chloride electrolytes 

 which contain suitable reducing agents such as 

 hydroxylamine or formalin. We have found since 

 that copper, bismuth and antimony can be de- 

 posited simultaneously, and can be separated from 

 tin and lead; that tin and lead can be deposited 

 simultaneously and separated from cadmium ; that 

 copper or bismuth can be separated from anti- 

 mony by dissolving alloys of these metals in nitric 

 acid plus tartaric acid and electrolyzing the so- 

 lutions with a limited cathode potential; that bis- 

 muth phosphate can be precipitated quantitatively 

 out of the same solution; that tin may be sepa- 

 rated completely from lead by dissolving an alloy 

 of these two metals in nitric acid plus potassium 

 nitrate; and that silver in silver chloride may be 

 determined by dissolving the latter in ammonia, 

 adding ammonium nitrate and electrolyzing. 



These facts are all combined in the following 

 systematic procedure for the rapid electroanalytical 

 determination of all the common metals the poten- 

 tials of which are more noble than that of cad- 

 mium. 



{A) Dissolve sample in hydrochloric acid or in 

 aqua regia; an insoluble residue — silver chloride — 

 is dissolved in ammonia plus ammonium nitrate, 

 and the silver determined electrolytically. 



(B) Treat solution A with hydroxylamine — mer- 

 cury, gold and platinum will be precipitated and 

 can be determined by well-known methods. 



(C) Out of filtrate B, remove arsenic by distil- 

 lation with hydrochloric acid, and determine ar- 

 senic iodometrically. 



