1880.] On the Absorption Spectra of Cobalt Salts. 



51 



leading member of which beryllium unquestionably is, stands certainly 

 in the nearest proximity with an other series, that of aluminium 

 (Al 2 , Gra 3 , Tn 2 , Cr 3 , Mn 2 , Fe 2 ), but this nevertheless decidedly differs 

 from the former by an other typical double sulphate, 



K 2 S0 4 +R 2 3S0 4 + 24H 2 0. 



or alum. 



The fact, which has been alleged as a proof of the bivalence of 

 beryllium, namely, that the chloride fuses and sublimes at a higher 

 temperature than aluminium chloride is of no importance, for it will 

 be found that amongst the members of the former series, with its 

 difficultly fusible and volatilisable chlorides, many analogies exist for 

 beryllium, not only in this but in many other respects. 



Lastly, we subjoin a table showing the magnetic properties of the 



o 



rare earths. Mr. Knut Angstrom kindly undertook this research, 

 employing a powerful electromagnet of RuhmkorfF, between the poles 

 of which the oxides showed the following properties : — 



Magnetic. Diamagnetic. 



Cr 2 3 Be 2 3 



Fe 2 3 A1 3 3 



T 2 3 Sc 2 3 ? 



Di 2 3 ln 2 3 



•A 



Tb 9 8 



Er 2 3 La 3 3 



— Zr0 2 



Ce0 2 ThOg 



III. " On the Absorption Spectra of Cobalt Salts." By W. J. 

 Russell, Ph.D., F.R.S., Treas. C.S., Lecturer on Chemistry 

 at the Medical School, St. Bartholomew's Hospital. Re- 

 ceived August 4, J 880.. 



(Abstract.) 



The following investigation was commenced with Mr. Lockyer, and 

 although he has been unable to continue the work, the author is 

 indebted to him for much aid and many suggestions. 



The cobalt salt first examined was the anhydrous chloride. In order 

 to establish clearly its absorption spectrum, different samples of this salt 

 were made by various processes. All, however, gave the same spec- 

 trum. The bromide of cobalt yields a similar spectrum, but its posi- 

 tion is different, it is nearer to the red. 



