July 21, 1905.] 



SCIENCE. 



75 



This method consists in slowly drawing a 

 known volume of air over the liquid whose 

 vapor tension is to be measured, the liquid 

 being placed in a large horizontal glass 

 tube which is constantly agitated to insure 

 complete saturation of the air with the 

 vapor, but not so as to produce spray. The 

 material thus carried over by the air is 

 absorbed in appropriate apparatus and 

 weighed. In the case of solutions a meas- 

 urement is also made with the pure solvent. 

 Apparatus for Vapor Heating: H. R. 

 Cakveth and J. P. Magnusson. 

 The paper reviews the various forms of 

 apparatus which have been suggested for 

 the determination of molecular weights by 

 the vapor heating method and presents a 

 new form. Its distinguishing feature is 

 that while it still permits of the return of 

 the condensed liquid to the boiling flask the 

 latter, being separate from the vapor 

 heater, may in case of breakage be readily 

 replaced. 



Tensile Strengths of Aluminum Zinc Al- 

 loys: AV. D. Bancroft. 

 A New Use for the Dilatometer: W. Lash 



Miller. 

 The Hydrolysis of Ammonium Acetate and 

 the Ionization of Water at High Tem- 

 peratures {100°-156°) : Arthur A. 

 NoYES and Yogoro Kato. 

 The figures below are computed from 

 conductivity measurements made with a 

 specially constructed apparatus previously 

 described. Percentage hydrolysis of am- 

 monium acetate at one one-hundredth nor- 

 mal (values vary but slightly with con- 

 centration) : at 18°, 0.5 per cent.; at 100°, 

 5.2 per cent. ; at 156°, 17 per cent. Ioniza- 

 tion constants: 



18° 

 100 

 156 

 218 



Water. 



0.66X10'* 

 48 

 155 

 200 " 



Acetic Acid. 



18.3 X IQs 



11.4 " 

 5.6 



1.9 " 



Ammonium 

 Hydroxide. 



17.1 X 106 

 14.0 

 6.6 



It will be noticed that the increase in the 

 constant of water and the decrease in those 

 of the acid and base act together in pro- 

 ducing increased hydrolysis at high tem- 

 peratures. 



Equilibrium in the ^System, Beryllium 



Oxide— Oxalic Acid— Water: Chas. L. 



Parsons and W. 0. Robinson. 



Equilibrium studies of the oxalates of 



beryllium show that the basic oxalates 



Avhich have found their way into chemical 



literature have no basis in fact, but are 



solid solutions of indefinite composition. 



The acid oxalate of beryllium also can not 



be made. The one definite compound of 



these three components is BeCo04 -\- SH^O 



at ordinary temperature and BeCaO^ -j- 



H2O obtained by heating the first to 100°. 



The Phosphates of Calcium: F. K. Cam- 

 eron. 



In the system Ca— Po^— HoO, the equi- 

 librium is reached at 25° C. at a slow rate. 

 The ratio P04/Ca in the solid phase was 

 found to be 4.6 at a concentration of Ca 

 above 55 grams, and of PO4 above 423 

 grams, per liter of solution. Between this 

 point and the second point, whose exact 

 position is still under investigation, the 

 ratio PO^/Ca in the solid phase was 2.4. 

 At lo-wer concentrations of PO4 the ratio 

 P04/Ca in the solid phase varied contin- 

 uously from about 2.1 to 0. This shows 

 that at higher concentrations the solid 

 phase is monocalcium phosphate; at inter- 

 mediate concentrations the solid phase is 

 dicalcium phosphate, and at lower concen- 

 trations there is one, or possibly tAvo, series 

 of solid solutions. 



The Transmutation of the Elements: H. 

 J. Barnes. 



A Strong, Sterilizahle, Dialyzing Mem- 

 brane: H. W. Hill. 



Some Notes on Rock Decompositions : Al- 

 lerton S. Cushman. 



