NOVEMBEB ], 1907] 



SCIENCE 



571 



heat, which increased regularly with the 

 temperature at which determined, until be- 

 tween 400° and 500° it approached normal 

 with a value of 6.2. A determination of 

 the vapor density of the bromide, of the 

 acetylacetonate and of the basic acetate, all 

 seemingly in agreement with the idea of the 

 divaleney of the element, would have 

 seemed to have settled the matter and prob- 

 ably has done so, but the controversy itself 

 goes merrily on. Wyrouboff still argues in 

 his articles for the trivalency and Tanatar 

 claims that the basic acetate can only be 

 explained on the supposition that the ele- 

 ment is in reality tetravalent. 



Of the binary compounds of beryllium 

 only the oxide, the carbids and the halides 

 have any real standing in literature, 

 although the sulphide has been made by 

 Lebeau. Of these the oxide is the only one 

 that is stable in ordinary moist air and even 

 it shows decided variability in its hydro- 

 scopicity for reasons not yet determined. 

 Ordinarily white, it is said to be blue by 

 Levi-Malvano when made from his hexa- 

 hydrated sulphate, although it is almost in- 

 conceivable that the difference of two mole- 

 cules of water in the sulphate should cause 

 this change and the existence of the hexa- 

 hydrate itself is not yet confirmed. The 

 halides, with the possible exception of the 

 fluoride, can only exist in the complete ab- 

 sence of water, which causes them immedi- 

 ately and violently to lose part of their 

 anion as hydraeid. In this respect they 

 are even more sensitive than the corres- 

 ponding compounds of aluminum. On 

 evaporating their solutions in water they 

 lose more or less of the remainder of the 

 gaseous hydracids, the residue becoming 

 more and more basic and remaining soluble 

 until a surprising degree of basicity is 

 reached. This hydrolytic action is com- 

 paratively small in the case of the fluoride, 

 but is practically complete in the case of 

 the chloride, bromide and iodide. By care- 



ful manipulation residues of almost any 

 degree of basicity, up to the pure oxide, 

 can be obtained, and these mixtures of base 

 and normal salt have given rise to claims 

 for numerous oxyfluorids and oxychlorides 

 for the existence of which there is no other 

 evidence than the analysis of the variable 

 residues obtained. 



The hydroxide of beryllium is one of the 

 most interesting of its compounds and one 

 that has properties which vary greatly with 

 the conditions of its preparation. Among 

 the most noteworthy may well be mentioned 

 its great solubility, of from two to five 

 equivalents, in concentrated solutions of its 

 own salts, and its precipitation therefrom 

 on dilution ; its solubility in saturated solu- 

 tions of acid sodium and ammonium car- 

 bonates, and its very much diminished sus- 

 ceptibility to reagents when dried at high 

 temperature or boiled in water, as instanced 

 by the fact that when freshly precipitated 

 and washed with cold water it will take up 

 one third of an equivalent of carbon diox- 

 ide, but on boiling becomes so immune to its 

 action that the gas has been passed through 

 it for three months without any consider- 

 able absorption. 



Probably the fact which has the greatest 

 bearing upon the chemistry of beryllium 

 and has caused more failures of researches 

 undertaken upon the element than any 

 other one thing, is the great infiuence which 

 water has upon all of its salts, acting to 

 many of them almost as if it were itself a 

 strong hydroxide and in a manner that is 

 hard to understand from our ordinary con- 

 ceptions of solution and hydrolysis. 



For this reason normal salts of the non- 

 volatile acids only can be crystallized from 

 water, and indeed but very few of them, 

 such as the sulphate, the selenate and the 

 oxalate have been so prepared. These are 

 so strongly acid in reaction that they act 

 almost as solutions of the acids themselves, 

 attacking metals with evolution of hydro- 



