30 



SCIENCE- 



[Vol. LVI, No. 1436 



cium, magneaium, lead and cadmium were trans- 

 posed from 91 to 97 per cent. Silver oxalate on 

 the other hand was transposed only to the extent 

 of 77 per cent. In determining the amount of 

 transposition it was necessary to analyze the 

 insoluble oxalates for their oxalate content. In 

 this work it was necessary to devise special pro- 

 cedures wherever the oxalate content could not be 

 directly determined as in the cases of ferrous, 

 cobalt, lead and stannous oxalates. These special 

 procedures are given in the original article. 



A new method for the vohimetrio determination 

 of iron: L. J. Curtman and N. H. Hbcht.. In a 

 previous communication (Chem. News, CXXII, 

 1921, p. 254) the authors proposed a rapid method 

 for roughly estimating the iron in systematic 

 qualitative analysis. In this method the iron, if 

 not already in the ferric condition, is first oxidized, 

 treated with KCNS and the deep-red Fe(CNS)^ 

 which form is bleached with a standard solution 

 of SnCl„. The results obtained by this method 

 were so surprisingly accurate that we undertook 

 a special study of the procedure to determine 

 whether or not it could be used as a substitute for 

 the standard volumetric methods for iron. Numer- 

 ous analyses of iron ores were made by our method 

 as well as by the Zimmerman-Eheiuhart and gravi- 

 metric methods. The results agreed very well, 

 showing the new method to be a reliable one. 

 The various factors which influence the results by 

 this method were studied and a suitable apparatus 

 was devised for preventing the oxidation of the 

 standard SnCl„ solution. Once the apparatus is 

 set up, our method will be found much more rapid 

 of execution than any of the old volumetric meth- 

 ods in which the iron is first reduced and then 

 oxidized. 



Two new pieces of apparatus for use in ana- 

 lytical work: Louis J. Cubtman. Having experi- 

 mentally demonstrated that 48 per cent. HF was 

 without appreciable action on transparent bake- 

 lite, the author had prepared for him from this 

 material a 10 cc graduate and a medicine dropper. 

 The former has been found very serviceable in 

 measuring definite quantities of HP. These 

 graduates are less brittle than glass, they are non- 

 inflammable, retain their shape and can be readily 

 cleaned. They are provided with a flared top to 

 facilitate pouring the HF from the usual wax 

 containers in which HF is supplied. The medicine 

 dropper made of transpareirt bakeHte has been 

 found superior to the improvised lead tubes which 

 have heretofore been used in carrying out one of 

 tlie best qualitative teats for silica and silicates. 



Sapid electrolysis without mechanical stirring: 

 Graham Edgar and E. B. Pukdtjm. By the use 

 of an electrolytic cell consisting of a vride glass 

 tube provided with three glass ' ' air lifts ' ' sealed 

 into its side and entering tangentially at their 

 upper ends, a vigorous stirring, both rotational 

 and vertical, may be effected by blowing or suck- 

 ing an air current through the air injectors. With 

 a cylindrical platinum gauze cathode and a spiral 

 anode in such a cell, rapid and accurate deter- 

 minations of copper have been made, using a cur- 

 rent of as much as three amperes and a time as 

 low as fifteen minutes. Zinc does not interfere. 

 The apparatus is readily constructed, and the 

 technique for its use is extremely simple. 



The relation of yield value and mobility to the 

 so-called painting consistency of paints: Eugene 

 C. Bingham and Herbert D. Bruce. 



Eydroux oxide IV: Hydrous Stannic. Oxide: 

 Harry B. "Weisee. The so-called alpha or 

 stannic acid and beta or metastannic acid are not 

 isomeric compounds but are the two extremes of 

 a series of hydrous stannic oxides that differ from 

 each other in solubility, peptizability, adsorba- 

 bility, the structure of the mass and the amount 

 of water contained. Peptization and adsorption 

 experiments on stannic oxides prepared at various 

 temperatures show that each is a chemical indi- 

 vidual and not a mixture of a definite alpha with 

 a definite beta oxide. Contrary to the usual ob- 

 servation, stannic oxide jellies may be prepared 

 by precipitation of the hydrous oxide from col- 

 loidal solution, under suitable condition. 



The interfacial tension between toluol and ash- 

 free gelatin solutions: S. E. Sheppard and 8. S. 

 Sweet. Measurements were made by means of a 

 drop pipette, the interfacial tension being calcu- 

 lated from the weight of a drop by Harkin'a 

 formula, the accuracy being checked by measure- 

 ments on water. It is found that gelatin lowers 

 the interfacial tension between water and toluol 

 considerably, a one per cent, at 30° C. lowers it 

 some 10 dynes/cm, and this increases with the 

 concentration of gelatin. The interfacial tension 

 or Pjj curve was determined for 1.0 per cent, ash- 

 free gelatin at 30°, 40° and 50°. Between 

 Pjj =: 1 and Pjj := 10 there is but little variation, 

 except for a well-marked and significant "kink" 

 at Pjj = 4.8, the iso-electrie point. At 30° and 

 40° C. there is but little change with time, but at 

 50° G. the change is considerable, except at the 

 iso-electric point, indicating hydrolj'sis. 



The nitration of toluene: James M. Bell. 

 Charles L. Parsons, 



Secretary 



