Weight of Beryllium. 67 



(2) Let us consider the numbers which express the volume 

 of oxygen in the oxides (see Table II. of the preceding paper). 

 Beryllium, with the number +2*7, again finds its right place 

 between lithium ( — 11) and boron ( + 8). Further, we see 

 that berjllia is the most feeble base in the group of the alka- 

 line earths : — 



BeO MgO CaO SrO BaO 

 + 2-7 -1-8 -7-2 -12-9 -8-5 



(8) Let us next examine the specific volumes of the sul- 

 phates of the first three groups. We find numbers in this way 

 corresponding closely with the position of beryllium II. — 2 

 (Mendelejeff). The specific volumes are referred to one atom 

 of sulphur in the molecule, in order to get comparable num- 

 bers : — 



I. 





ii. ni. 



Li 





Be B 



49-8* 





43-0 — 



Na 





Mg Al 



54-6 





44-3 42-2 



K 





Ca Sc 



67-0 





46-6 48-6 



Zn 45-6 



Sr Y 



47-1 59-6 



Ag 



76-3 



Ba La 

 51-8 52-4 



In 49-9 



If beryllium were placed in the third group as a triad before 

 aluminium, the volume of its sulphate ought to be smaller 

 by some units than 43, i. e. about 40. But meanwhile, from 

 the equation 



Li:Mg = Be: Al 



it follows that the volumes of the sulphates of every couple of 

 those metals will not have very different values, as indeed we 

 have seen in the case of the oxides. 



(4) Let us next take the molecular heats of the oxides which 

 have the number of oxygen atoms corresponding to the num- 

 bers of Mendelejeff's group. Expressing the molecular heats 

 with respect to one atom of metal in the oxide, we get the 

 following numbers: — 



* Deduced from the specific gravity, which I found to be 2-21 at 15° 0. 



F 2 



