66 Dr. B. Brauner on the Atomic 



earths and tlioir sulphates ; and they find therein a further 

 confirmation of their views respecting beryllia. 



The first part of the paper of Messrs. Nilson and Pettersson 

 has been thoroughly discussed by Professor Lothar Meyer*, 

 who showed that from their own experiments a conclusion 

 opposite to that of the above-named authors may be drawn, 

 viz. that beryllium is a dyad, inasmuch as it belongs to a class 

 of elements in which the specific heat increases with the tem- 

 perature, but in which the increment for 1° C. regularly dimi- 

 nishes, the opposite of this being the case with metals obeying 

 the law of Dulong and Petit. Lothar Meyer concludes there- 

 from that beryllium is a dyad, Be // = 9*1. 



The aim of the present communication is to discuss the 

 second part of the researches of Messrs. Nilson and Pettersson. 

 These experimenters find that beryllia possesses a molecular 

 heat and molecular volume nearly equal to those of the other 

 rare earths ; and they go on to state that, if the formula BeO 

 for beryllia be accepted, values for the above relations are ob- 

 tained which are without analogy in the whole range of the 

 science. 



On this point I would beg to remark: — 



(1) If we consider beryllia as BeO, its molecular volume is 

 8'3. And if the oxides be arranged according to the periodic 

 law (see the preceding paper), this number exactly corresponds 

 to the position of a dyad beryllium. For beryllium thus 

 stands between lithium and boron. The same is the case if 

 we consider the vertical groups 



I. 



II. 



III. 



Li 7 



Be 8 



B 19 



Nail 



Mgl2 



A113 



K 17 



Ca 18 



Scl8 



If we consider the specific volume of beryllia, compared 

 with the same quantity of oxygen as that contained in alumina, 

 we get the same number as would be given by the supposed 

 oxide of trivalent beryllium, -JBe 2 3 . We get the number 

 12'5, which is nearly equal to that of ^Al 2 3 = 13. But in 

 the same way the double volume of lithia, 2 x 7 = 14, is nearly 

 equal to that of magnesia = 12. The same relations are shown 

 by the oxides of boron and silicon; for f vol. B 2 3 (25*3) = 

 1 vol. Si0 2 (23). But the explanation of this relation is given 

 by the equation 



Li:Mg = Be : A1 = B : Si, 



following from the periodic law. 



* Berliner Beriehte, xiii. p. 1780. 



