1825.] M. Berzeliits on Uranium. 271 



this analysis as more decisive than that of any of the preceding; 

 for if the oxide of uranium were otherwise constituted, a very 

 dift'erent quantity of muriate of silver ought to have been 

 obtained. If, for example, we suppose that the uranium in this 

 experiment had been combined with 4*96 instead of 4*47 parts 

 of oxygen, the quantity of muriate of silver ought to have been 

 r684 grm. ; but the difi'erence between this and the experimen- 

 tal result greatly exceeds what could possibly be occasioned by 

 any errors of observation. Indeed if the oxide of uranium con- 

 tained 5 atoms of oxygen, it is not probable that it could have 

 existed associated with potash in the above-mentioned relation, 

 where the oxygen of the oxidule is two-thirds that of the potash, 

 but that the oxygen both of the oxide of uranium and of the 

 potash would most probably have been the same : still, on this 

 supposition, there ought to have been received 1-67 grm. of 

 muriate of silver. The proportions which, next to these, would 

 approach most nearly to the analytical result, would be when 

 the oxygen of the oxide is to that of the potash as 5 : 4 ; but 

 this would presuppose still greater differences both in the quan- 

 tity of muriate of silver, and in the relative proportions of the 

 potash and oxide of uranium. 



Since the quantity as well as the number of atoms of the oxy- 

 gen may in this manner be regarded as known, the information 

 thus acquired may be applied to the analysis of other compounds 

 of uranium. 



The oxalate of uranium gave, in one experiment, from 2*67 

 grm. of the desiccated salt, 0'353 grm. water, 0'5835 grm. car- 

 bonic acid, and 1"7335 grm. metallic uranium. This approaches 

 to the neutral oxalate of uranium, combined with a quantity of 

 water of crystallization whose oxygen is thrice that of the oxide. 



By calculation. By experiment. 



Oxide of uranium. .. 70-76 69*00 



Oxalic acid 16-73 17-99 



Water 13-51 13-01 



Another quantity of the oxalate which I subjected to analysis 

 appeared to be a subsalt, in which the oxygen of the oxalic acid 

 and of the water was the same, and each double that of the 

 oxide. But the tendency of oxide of uranium to combine with 

 a different base is so powerful, that I do not consider this expe- 

 riment as in any respect decisive. 



The hydrate of oxide of uranium is readily soluble in bicar- 

 bonate of potash, and the solution after some time deposits an 

 incrustationof lemon yellow coloured crystals, which constitute 

 a double salt, composed of carbonic acid, oxide of uranium, and 

 potash. When these crystals are ignited, they give ofl' water 

 and carbonic acid, and assume a tile red colour. Water extracts 



