July 8, 1904.] 



SCIENCE. 



41 



therefore, it seems that the moisture left in 

 a gas by phosphorus pentoxide is nil. A 

 gas may be made as dry as the figures indi- 

 cate, by passing at the rate of two liters an 

 hour through 25 c.c. of phosphorus pent- 

 oxide. The difficulty often experienced in 

 filling a glass apparatus with a perfectly 

 dry gas is due to the wetting of the dried 

 gas by the water persistently adhering to 

 the surface of the glass. 

 Bromides of Ruthenium: Jas. Lewis Howe. 

 These compounds were prepared by 

 the action of hydrobromie acid upon 

 ruthenium tetroxide. Addition of alkali 

 bromides gives brom-ruthenites of the 

 formula Xj'RuBrj, which, when boiled 

 with dilute alcohol acidified with hydro- 

 bromie acid, give aqua brom-ruthenates, 

 X,'Ru(H20)Br5. The latter form, on ad- 

 dition of bromine, the salts Xa'RuBrg. All 

 of these salts are analogous and similar to 

 the corresponding chlorides. 

 Changes in the Composition of the Ferro- 

 cyanides of Cadmium, Zinc and Man- 

 ganese after Precipitation: E. H. Miller 

 and M. J. Falk. 



Several new double ferrocyanides of 

 cadmium, ammonium and potassium were 

 described. The investigation also showed 

 that the precipitate formed in the ordinary 

 titration of zinc in the presence of am- 

 monium chloride is an ammonium potas- 

 sium zinc ferroeyanide, and not K2Zn3Fe 

 (CN)^ as given heretofore. 

 Silica Determinations : Harrison Everett 



Ashley. 

 The Atomic Weight of Beryllium: C. L.. 

 Parsons. 



An abstract of this paper has recently 

 appeared in Science in a report of a meet- 

 ing of the New York section (p. 923). 

 The ' Drop ' Method for Surface Tension 

 as a Means for Ascertaining the Molec- 

 ular Weight in the Liquid State: J. 

 Livingston R. Morgan. (By title.) 



Tlie Constitution of the Brasses: Wilder 



D. Bancroft. 



Six sets of solid solutions crystallize from 

 molten mixtures of copper and zinc. Be- 

 low 400° only five of these are stable. The 

 a crystals (100-63 per cent, copper at 

 400°) are yellow, the /? crystals (54^-51 

 per cent, copper) are reddish, while the 

 other four series are silvery. Brasses con- 

 taining 51-40 per cent, copper consist of 

 a mixture of brittle silvery crystals and 

 ductile reddish-yellow crystals. An alloy 

 containing 43 per cent, of copper was 

 shown in which the fracture was silvery, 

 while the polished surface was yellow. 

 The Transport Number of Sulphuric Acid: 



0. F. Tower. 



Experiments were made with normal, 

 one half normal, one fifth normal, one tenth 

 normal, one twentieth normal and one 

 fiftieth normal acid and at the tempera- 

 tures 8°, 20° and 32°. 



It was found that the transport number 

 decreases with the concentration and is 

 practically constant at the concentrations 

 one twentieth and one fiftieth normal. The 

 average value found at these concentrations 

 was 0.180 at 20°. At other temperatures 

 between 8° and 32° the following equation 

 holds : 



«,=:0.18° -f 0.0011(^ — 20°). 

 The Hydration of Milk Sugar in Solution: 



C. S. Hudson. 



By determinations of the initial and final 

 solubility of solid milk sugar hydrate and 

 milk sugar anhydride, conclusions are 

 drawn as to the state of hydration of milk 

 sugar molecules in solution. The change 

 in the hydration proceeds so slowly as to 

 be accurately followed, and the results ob- 

 tained by other methods are in entire 

 agreement. 

 Migration of Colloids: W. R. Whitney 



and J. C. Blake. (By title.) 

 The Vapor Pressure of Sulphur at 100° C: 



HrppoLYTE Gruener. 



