Dr. Kane on the Compounds of Ammonia. ,85 



1. CMO . SO3 . CMO + 2CMO. 



2. zno SO3 . z?io -{- 2 zno. 

 which are those most easily formed, and most permanent. 



A great number of circumstances conspire to render the derivation of the 

 basic sulphates of the magnesian class, from the neutral condition, exceedingly 

 complicated. Thus the neutral salts crystallize with quantities of water variable 

 within very extensive limits, and the proportion of metallic oxide by which it 

 may be replaced, is subject to fluctuations equally wide : moreover, the replace- 

 ment of the water by metallic oxide may be but partial, and hence the different 

 hydrated conditions in which the basic salts exist. From these causes may be 

 deduced the possible existence of a very extensive series of basic sulphates vary- 

 ing considerably in type, and subject only to the one restriction, that in all their 

 different conditions the sum of the equivalents of water and metallic oxide shall 

 always be equal to the sum of the same constituents in some one of the forms in 

 which the neutral salt may crystallize. So that the general expression of the 

 class becomes 



RO . SO3. v o -f- 2re > o. 



> indicating the sum of the mutually replacing elements. In the synopsis of 

 the analytical results of the basic sulphates contained in the sections on the cop- 

 per and zinc compounds, the instances given can be so immediately compared 

 with the above expression, that it is not necessary to reinsert them here. 



Although the general form of the crystallized chlorides of the magnesian 

 group of metals, as was well shown by Graham, consists in the adhesion of pairs 

 of equivalents of water, yet in the construction of the basic chlorides or chlor- 

 oxides the form pointed out for the nitrates and some basic sulphates is adopted; 

 thus, the ordinary chloride of copper, cmc^-1-2ho, cannot be obtained in combi- 

 nation with more water, but the tendency to assume the fourth molecule is shown 

 in its basic forms, thus it may become 



cud -j- 2 cuo, 

 and thence 



CUCl-\-2 CUO -{- CMC 



cucl-\-2cuo-\-no 



cud -\- 2 CUO -\- HArf 



as has been already noticed in another point of view. 



