SELENIUM. 103 



R GoDEFFROY : 85.476 (0 = 16). 



Determined by four analyses of rubidium chloride prepared 

 and analysed exactly as Godeffroy determined caesium, q. v.; 

 extreme difference, 0.04. CI = 35.5 ; Ag = 108. [Liebig's 

 Ann., 181, 1877, 189.) 



RUTHENIUM. 



Bunsen has determined the specific heat of ruthenium. 

 It corresponds to an atomic weight of about 104. [Gmelin- 

 Kraut, I. c.) 



C. E. Glaus : 104,.S7 (0 = 16). 



Determined from three analyses of potassium chlororuthe- 

 niate by the same method Berzelius had employed for other 

 platinum metals. Glaus found an average of 28.783 per 

 cent. Ru ; extreme difference 0.48, and 41.063 KCl ; ex- 

 treme difference, 0.51. [If K = 39.137, Gl = 35.457; this 

 composition gives Ru = 104.57. Tlie weighings as given 

 in the memoir are misprinted.] Glaus also determined 

 the chlorine with silver; the results were such as to show 

 that the salt was not anhydrous, though it had been dried 

 at 200° in an atmosphere of CI. The salt was prepared by 

 the evaporation of a solution of ruthenium and potassic 

 hydrate in aqua regia, solution of other chlorides of Ru in 

 dilute HGl, and removal of basic compounds by mechanical 

 concentration in water. Glaus later takes the atomic 

 weight of Ru = 104. In this memoir he puts it at 651.387 

 (0 = 100,) 104.£2 (O = 16,) without mentioning the values 

 of K and Gl. {Poggend. Ann., 65, 1845, 218.) 



SELENIUM. 



Regnault determined the specific heat of selenium, which 

 accords with an atomic weight of about 79. {Gmelin- Kraut, 

 I. c.) 



