November 7, 1919] 



SCIENCE 



443 



counts made on both Palmer and high tension sus- 

 pensions, showed, on a percentum basis, that the 

 Palmer apparatus collected 59.9 per cent, of total 

 particles counted in the high tension suspensions, 

 63.3 per cent, of the total sedinient, 66.6 per cent, 

 organic portion, and 55.2 per cent, inorganic por- 

 tion collected by the electrical machine. Based on 

 total sediments collected per 240 cubic feet of air 

 in each process whose air was sampled, the Pal- 

 mer collected 63 per cent, of the amount retained 

 by the electrical method. The conclusions are that 

 the Palmer apparatus under similar conditions is 

 61.6 per cent, as efficient as the electrical method 

 (•average of above figures). The electrical appa- 

 ratus used is too bulky for ordinary field work, 

 and suggestions are made for its simplification. 

 It is felt that the findings warrant further study 

 of the electrical precipitation method as applied 

 to the sanitary analysis of air. 



DIVISION OF PHYSICAL AND INORGANIC CHEMISTRY 



W. E. Henderson, Clmirman 

 W. A. Patrick, Secretary 



The vapor pressures of mercury in the range 

 ISO" to S50° : Alan W. C. Menzies. Two Mc- 

 Leod gauges containing dry hydrogen over pure 

 mercury were connected with the same pressure 

 reservoir. One of the gauges was raised to the 

 desired temperature and both gauges then operated 

 simultaneously. The vapor pressure of mercury 

 was calculated from the difference, due to mer- 

 cury vapor, of the pressure readings given by the 

 hot and the cold gauges respectively. 



The vapor pressure^ of tetranitromethane : Allan 

 W. C. Menzies. These measurements covered the 

 range 40° to 126°, thus including the solution of 

 War Problem No. 142 of the National Research 

 Council. The entropy of vaporization of this 

 liquid appears to be normal. 



Production of hydrochloric deid from chlorine 

 and water: H. D. Gibbs. 



Opening up minerals with phosgene: Charles 

 Baskeeville. The bleaching of ferruginous 

 silicous bricks by the action of phosgene in plants 

 where that poisonous gas was manufactured has 

 been noted. The useful application of this method 

 of conversion of iron oxides into volatile ferric 

 chloride, with a bleaching, for glass-sand, was 

 suggested by Hulett. Phosgene under the influ- 

 ence of heat is very reactive at temperatures of 

 450° C. and above. We have converted oxides of 

 aluminum and cerium, insoluble in acids, oxides of 

 zirconium and thorium, insoluble in acids except 



boiling concentrated sulphuric acid, directly into 

 water soluble chlorides or oxy-chlorides. Bauxite 

 and carborundum yield ferric and aluminum 

 chlorides. Zirconium chloride has been distilled 

 from zircon (silicate), ferric chloride from the 

 contaminating iron being fractioned away due to 

 its greater volatility. The silica remains behind. 

 Thorianite yields soluble thorium and uranium 

 chlorides. The procedure is very simple. The 

 pulverized material is heated in a quartz tube in a 

 stream of gaseous phosgene. It is proposed to ex- 

 tend the work to a large number of the rare- 

 earth minerals. 



The preparation of colloidal gold and silver by 

 new reducing agents: Harry N. Holmes. 



P7ia.se rule studies of the nitrotoluenes : C. H. 

 Herty, Jr. 



Compression by adsorption: William D. Har- 

 KiNS and D. T. Ewmo. 



The worh done by the attraction between a mer- 

 cury surface and the surface of an organic sub- 

 stance : W. D. Harkins, E. H. Grafton and D. T. 



EWING. 



The change of molecular Tcinetic into molecular 

 potential energy: William D. Haekins and L. E. 



EOBESTS. 



The separation of yttrium from the erbium 

 earths: P. H. M. P. Beinton and C. James. 



A new method for the determination of zircon- 

 ium: M. M. Smith and C. Jambs. 



The effect of lead upon thorium nitrate in aque- 

 ous solution : Fanny R. M. Hitchcock. 



An electrometric study of the neutralization of 

 monocalcium phosphate: Gerald Wendt, A. H. 

 Clarke and S. M. Weisman. 



The existence of an ozone form of hydrogen: 

 Geeald L. Wendt and Rob. S. Landauek. 



Action of thiosulfate on arsenate in acid 

 solution: Geo. Shannon Forbes and O. J. 

 Walker. Thiosulphate in excess precipitates 

 AsA from H3ASO4 in HCl (Vortmann, 1889). We 

 combined reactants, varying one concentration at a 

 time, and plotted S.^Oa/HsAsO, against HCl/HsAsO, 

 for incipient precipitation. Given one concentra- 

 tion constant, any curve has a horizontal part 

 along which S2O3/H3ASO4 :;= k = 2, meeting a 

 nearly vertical part when HCl/HjAsO., = 2. This 

 indicates a complex, H3As04(HS203)"2, but its 

 average hydrogen content decreases with increas- 

 ing S;0"3. Trithionate, with thiosulphate, ac- 

 companies A&iSb along the "vertical" lines. 



2H3As04. (HSA)/' -f 6HS3O3' 



= AS2S5 -f 5S3O/' + 8H,0. 



