June 17, 1904.] 



SCIENCE. 



923 



THE AMERICAN CHEMICAL SOCIETY." 

 NEW YORK SECTION. 



At the eighth regular meeting of the season, 

 held on May 6, at the Chemists Club, 108 

 West 55th Street, the following papers were 

 presented : 

 A Revision of the Atomic Weight of 



Beryllium. C. L. Parsons. 



The paper opened with a summary of the 

 previous determinations of the atomic weight, 

 all of any importance having been made upon 

 the tetra-hydrous sulphate. Following this 

 the results of investigation upon the chloride 

 and sulphate were given, in which it was 

 shown that Arodejew's BeCl^ -411,0 and 

 Klatzo's BeSO, -711,0 do not exist — that the 

 chloride is extremely difficult to obtain per- 

 fectly pure, and that the hydrous sulphates 

 lose water so easily under different equi- 

 librium conditions that they are not safe com- 

 pounds for atomic weight data. 



Determinations of the atomic weight were 

 made upon carefully purified beryllium aeetyl- 

 acetonate and basic beryllium acetate. These 

 compounds lend themselves with especial ad- 

 vantage to the determination of the atomic 

 weight of beryllium as they contain no crystal 

 water and are themselves readily crystallized 

 and sublimed. This is especially true of the 

 basic acetate — a compound peculiar to beryl- 

 lium alone. . Spectroscopic examinations of 

 the residues made by Professor Charles A. 

 Hutchins, of Bowdoin College, failed to detect 

 any impurity. The average of seven analyses 

 on the acetylacetonate and of nine on the 

 basic acetate gave the result : Atomic weight — 

 Be = 9.113. 



Incidentally a new crystalline compound of 

 beryllium chloride, ether, water and hydro- 

 chloric acid was described and it was shown 

 that the black precipitate mentioned by Kress 

 and Moralit, and which they evidently thought 

 must contain a new substance, was a mixture 

 of the sulphides of zinc and iron. 



The Dissociation of Lead Nitrate: J. Liv- 

 ingston E. Morgan. 

 Using the data of Baekeland (J. Am. Chem. 



Soc, XXVI., 391-399), the author showed that 



at 357° C. the dissociation constant of the re- 

 action Pb (NO3) , g=s PbO + + 2N0, is 

 0.062 when the partial pressures in the applica- 

 tion of the law of mass action, 



y/po X p'no, = constant, 



are given in meters of mercury. The pres- 

 ence of an excess of oxygen makes the reaction 

 abnormal in that it favors the formation of 

 oxygen-richer basic salts of lead; while nitro- 

 gen peroxide retains the equilibrium in the 

 above form. 



By aid of van't Hoff's formula it was also 

 shown that at the average temperature of 262° 

 C. the heat of dissociation is 579, the experi- 

 mental value being 578 Ostwald calories. At 

 higher temperatures the variation between 

 calculated and observed values is great, point- 

 ing to the presence of other compounds pos- 

 sessing different heat values. 



The Action of Sulphuretted Hydrogen on 

 Alkaline Solutions of Zinc Salts: LeEoy 

 W. McCay. 



Sulphuretted hydrogen precipitates from 

 alkaline solutions of zinc salts zinc hydrosul- 

 phide which dissolves completely when the gas 

 is allowed to bubble through the solution for 

 some time. As, if sulphuretted hydrogen be 

 passed into a solution of zinc acetate until all 

 the zinc is precipitated as zinc sulphide, on add- 

 ing a small amount of caustic alkali and again 

 passing the current of sulphuretted hydrogen 

 through the solution the zinc sulphide dis- 

 solves. The reaction is important, as it has 

 a direct bearing on- analysis (detection of zinc 

 in the alkaline filtrate from manganese hy- 

 droxide). The solution soon becomes turbid 

 from the separation of zinc sulphide. If the 

 liquid be mixed with concentrated solution of 

 the caustic alkalies, or with concentrated solu- 

 tions of alljali salts, a white, slimy precipitate 

 instantly separates out which contains all the 

 zinc. It would seem that the oxygen and sul- 

 phur compounds of zinc are analogous and 

 that corresponding to the alkali zincates there 

 is a class of compounds which may be called 

 the alkali sulphozincates. 



