324 



SCIENCE 



[N. S. Vol. XLIV. No. 1131 



precipitant instead of ammonium salicylate, but 

 the latter is preferable. 



The Electromotive Forces of Concentration Cells 

 and their Relation to the Transference Number: 

 D. A. MacInnes. 

 The Complete Solubility Curve of Calcium Car- 

 bonate: John Johnston. 

 The Specific Conductivity of Pure Water in Equi- 

 librium with Atmospheric Carbon Dioxide: 

 James Kendall. 

 An Apparatus for Determining Freezing -Point 

 Lowering: K. G. Van Name and W. G. Brown. 

 The Colloidal Phosphates and Arsenates of Iron: 



Harry N. Holmes. 

 The Formation of Crystals in Gels: Harry N. 



Holmes. 

 The Potential of Iodine Concentration Cells: 



Grinnell Jones. 

 A Supposed Effect of the Form of Container upon 

 the Density of a Gas: William A. Notes and 

 Laurence C. Johnson. 



In an effort to explain the difference in the vol- 

 umetric ratio of hydrogen to oxygen in water as 

 determined by Morley and by Scott, the volume oc- 

 cupied by a gas in a system of tubes has been com- 

 pared with that occupied by the same mass of gas 

 in a bulb. It has been shown that there is no dif- 

 ference in volume larger than one part in ten 

 thousand, whereas the two determinations referred 

 to differ by one part in one thousand. 



A Demonstration of the Selective "Action" of 

 Clay on Soluble Sulphides: John C. Ingram. 



The Theory and Mecha7iism of Adsorption : Irving 

 Langmuir. 



The Oxides of Iron. II. Magnetic Properties of 

 the System Fe 2 3 -Fe s i : E. B. Sosman and 



J. C. HOSTETTER. 



The Dissociation of Ferric Oxide in Air: J. C. Hos- 



tetter and R. B. Sosman. 

 On the Measurement of the True and Apparent 

 Electrical Conductivities of Solutions: Induc- 

 tance, Capacity, Frequency and Resistance Re- 

 lations: H. P. Hastings, W. A. Taylor and S. 

 P. Acree. 

 Separation of the Elements of the Tin Group: J. 

 M. Welch and H. C. P. Weber. 

 A very characteristic combination of tin and 

 antimony sulfide, which is always formed when tin 

 and antimony are precipitated together, is utilized 

 as an indication of the presence of these two ele- 

 ments. The compound formed, which is probably 

 a salt of thioantimonic acid, has not been isolated 



as yet, but a few compounds of the type are known. 

 The reaction is characteristic for all mixtures of 

 tin and antimony lying between 1:20 and 20:1. 



The procedure consists in obtaining this brown- 

 black color reaction, redissolving the sulfides with- 

 out separation, precipitating the antimony as sul- 

 fide from an oxalate solution and reducing the 

 stannic chloride in the filtrate to stannous chloride 

 with metallic lead. 



The process described is shorter and its use by 

 students has resulted in a material decrease in the 

 number of errors (as shown by statistics) in the 

 work done. 



Differential Iodimetry. III. Determination of 

 Vanadium in the Presence of Iron and Uranium: 

 O. L. Barnebey. 

 Differential Iodimetry. II. Determination of 

 Chromium in the Presence of Iron: O. L. Bar- 

 nebey. 

 Precipitation of Magnesium Ammonium Ortho- 

 phosphate: Edward G. Mahin. 

 Some Laboratory Experiments on the Extraction 

 of Radium from Camotite Ores: A. G. Loomis 

 and Herman Schlundt. 

 A System for Reports on Quantitative Analysis to 



be used in Teaching: E. Gill. 

 The Action of Anhydrous Aluminium Chloride 

 upon Unsaturated Hydrocarbons: W. E. Hen- 

 derson and W. C. Ganglopf. 

 The Determination of Solubility Curves by the 

 Method of Flotation: W. E. Henderson and 

 Gebhart Stegeman. 

 Determination of Transition Points by the Meas- 

 urement of Electromotive Force: W. E. Hender- 

 son and I. W. Geiger. 

 A Systematic Procedure for the Separation of the 

 Anions: First Group: H. A. Winckelmann and 

 H. C. P. Weber. 



The problem of the systematic separation of 

 acids, which has received very little attention in 

 analytical methods, is an especially important one 

 in connection with instruction in chemistry, and 

 possibly of more importance generally than is 

 realized. Actually, very little has been done in 

 the subject. 



By means of the plan outlined mixtures contain- 

 ing any or all of the radicals, ferrocyanide, ferri- 

 cyanide, cyanide, thiocyanate, chloride, bromide, 

 iodide, sulfide, in quantities varying from to 100 

 mg. may be satisfactorily analyzed, and their 

 amounts estimated. The steps can not well be 

 presented in abstract, but the manipulations are 

 the customary ones of qualitative analysis, the 



