M. H. Rose on a new Series of Metallic Oxides. 365 



and has the same form as the native vitreous copper (Kwpferglanz) , 

 Cu 2 S*. 



Although it indubitably follows from these facts and nume- 

 rous others that the atomic weight assumed by Berzelius for 

 silver must be changed, this change has scarcely been accepted 

 by any chemist. Almost all assume, as hitherto, that oxide of 

 silver consists of an atom of metal and an atom of oxygen, and 

 consider that in composition it is analogous to oxide of copper 

 and oxide of lead, and not to suboxide of copper and suboxide 

 of mercury. 



Yet, on the other hand, it cannot be denied that there are 

 also weighty reasons for the retention of the universally adopted 

 atomic weight of silver. The chief reason against halving the 

 atomic weight of this metal is doubtless the fact that some com- 

 pounds of silver would acquire an altogether unusual composi- 

 tion. For if we assume that in oxide of silver 2 atoms of the 

 metal are combined with 1 atom of oxygen, suboxide of silver 

 will contain no less than 4 atoms of metal for 1 atom of oxygen. 

 This composition appears so entirely unusual, that the numerous 

 reasons which speak for changing the atomic weight of silver 

 have been disregarded, and the old assumption has been retained. 



When such an unusual composition is assigned to a compound 

 as the suboxide of silver, assuming that it consists of 4 atoms of 

 metal for 1 of oxygen, this assumption will always be doubted 

 until analogous compounds have been discovered whose compo- 

 sition can be explained in no other way. 



Hence I have taken much trouble to prepare oxides of the same 

 composition as suboxide of silver, and after many fruitless expe- 

 riments I have been successful. I have succeeded in obtaining 

 an oxide of copper which contains twice as much oxygen as sub- 

 oxide of copper, and hence is analogous to suboxide of silver. I 

 have hitherto not succeeded in preparing a similar oxide in the 

 case of mercury, but I hope to do so. I shall further show that 

 the number of such oxides is by no means small, but that their 

 preparation will be attended with great difficulties. 



Nomenclature. 



Before I proceed to describe the preparation and properties of 

 the new copper compound, it is necessary to assign a name to 

 this class of oxides, whose chief representative is suboxide of silver. 



Chemical nomenclature, more especially the German, is very 

 imperfect. The most imperfect, however, is the designation of 

 the different metallic oxides ; it is not only inconvenient, but 

 may give rise to much confusion. Originally we only had names 

 for two oxides ; and when several were discovered, help was 

 * Poggendorff" s Annalcn, vol. xxviii. p. 427, and vol. xl. p. 313. 



