418 Campbell — Caesium- Cobalt and Cozsium- Nickel 



specimens as to the process or details of its manufacture ; a 

 fact which is greatly to be regretted since, for instance, a 

 knowledge of the circumstances to which the failure in the 

 case of the imperfect glass was due would throw light on the 

 crystallization of the copper. 



It seems that the glass is produced by melting together glass, 

 cuprous oxide and some reducing agent, such as siderite,* and 

 that FeO is in this case the reducing agent is shown by the 

 greenish color of the imperfect glass, which is not the blue 

 green of copper but the yellow green of ferrous glass, and 

 perhaps due to too large a quantity of reducing agent. This 

 part of the subject, however, as well as the chemical composi- 

 tion of the glass I must for the present leave aside. 

 Venice, Italy, Aug. 25, 1894. 



Art. LX. — On the Cmium- Cobalt and Ccesium-Nickel 

 Double Chlorides, Bromides and Iodides / by G. F. Camp- 

 bell. 



As a continuation of the work in this laboratory on double 

 halogen salts, the investigation of the above-mentioned com- 

 pounds has been taken up. The study has been made in a 

 systematic manner with the view of preparing as complete a 

 series as possible. The salts obtained belong to three types, 

 and are as follows : 



3 : 1 Type. 2 : 1 Type. 1 : 1 Type. 



Cs 3 CoCl B Cs 3 CoCl 4 CsCoCl 3 . 2H 2 



Cs.CoBr, Cs 2 CoBr 4 



Cs 2 CoI 4 



CsNiCl 3 

 CsNiBr 3 



The results show that cobalt forms double salts with much 

 greater facility than nickel, for with the latter metal only the 

 chloride and bromide of a single type could be obtained. 



The series illustrates the increase in ease of formation of 

 double salts from the iodides to the chlorides, which has been 

 previously observed, especially in the case of the csesium-mag- 

 nesium salts by Wells and Campbell. f ~No csesium-nickel 

 iodide could be prepared. 



It should be noticed that the two salts of the 3 : 1 type are 

 exceptions to Remsen's law concerning this class of bodies. 



* Wagner-Fischer, Handb. d. Chem. Tech., 1889, pp. 707 and 741, quoted by 

 Vogt. 



f This Journal, xlvi, 432. 



