88 Dr. Kane on the Compounds of Ammonia. 



likewise, a consideration of the problem, whether a second oxide be a combina- 

 tion of metal with oxygen, or of oxygen with the first oxide, which I must 

 consider as decided by the circumstance of the atomic weight containing one or 

 two equivalents of oxygen. Thus I look upon the study of the salts of mercury 

 as decisive upon the red oxide of that metal being protoxide, but the examination 

 of the compounds of manganese assigns to the black oxide the form (ivino) -\-o. 



A remarkable fact in the history of the alkaline salts suggests an extension of 

 the views here discussed, which is thrown out as a speculation, and to which I 

 do not wish to attach otherwise importance. The sulphate of ammonia may be 

 written on the ammonium theory, SO3+0. (nh^), or SO3-J- o(ha</h) ; and 

 the ammonium being a basic amidide, it results that the ammoniacal salts 

 are all basic salts ; hence the condition which the salts of the magnesian class 

 may be made artificially to assume is that naturally belonging to those of the 

 ammoniacal series. Now as the ammonia and potash salts assimilate so com- 

 pletely, the speculation may be hazarded, that research will discover in potas- 

 sium a structure analogous to that which I have argued to exist in the so called 

 ammonium, and the result may show that the reason of the alkalies not producing 

 basic salts, arises from the circumstance of their salts being already basic in their 

 common form. 



SUPPLEMENTARY NOTE 



ON A COMPOUND HITHERTO CONSIDERED AS WHITE PRECIPITATE. 



Some time since I learned that Professor Woehler had found that the white pre- 

 cipitate in the possession of some Hanoverian apothecaries differed in many 

 important particulars from that which formed the subject of my researches, as 

 well as of the experiments of verification made by Ullgren. The body in ques- 

 tion had been prepared by precipitating a solution of sal alembroth by potash in 

 the cold. The precipitate which is produced, resembles externally the true white 

 precipitate so completely as to have been always taken for it, and hence in many 

 pharmacopoeias this process is given for preparing white precipitate for medicinal 

 purposes. It is, however, quite different in its nature, and as its analysis is of 

 importance as well in a practical as in a theoretical point of view, the following 

 brief description of its nature is subjoined : 



