1T7 



has published, a method of obtaining the above-mentioned liquid, 

 which never fails. 



" By taking the reasoning on this subject in its widest extent, 

 Mr. Chenevix thinks we shall be led to conclude, that metals may 

 exercise an action upon each other, even in their metallic state, ca- 

 pable of so altering some of their principal properties, as to render 

 the presence of one or more of them not to be detected by the usual 

 methods. In this is contained the possibility of a compound metal 

 appearing to be simple. But to prove this proposition must be a 

 work of great time and perseverance, and can only be done by con- 

 sidering, singly and successively, the different cases which it con- 

 tains, and by instituting experiments upon each." 



As an example of the foregoing position, and to prove that mercury 

 and platina act upon each other so as to disguise the properties of 

 both, Mr. Chenevix states, that when a solution of green sulphate of 

 iron is poured into a solution of platina, no precipitate, nor any other 

 sensible change, ensues ; but if a solution of silver, or of mercury, be 

 added, a copious precipitate, in part metallic, takes place. He has 

 tried to produce the same effect with other metals and platina, but 

 has not observed anything similar. From this he thinks it fair to 

 conclude, that " whenever a solution of platina is precipitated, in a 

 metallic state, by a solution of green sulphate of iron, either silver or 

 mercury is present. He adds, that the precipitation of a mixed so- 

 lution of platina and silver, requires no further caution than to free 

 the salt of platina, as much as possible, from muriatic acid." 



Mr. Chenevix then makes some observations, which cannot well 

 be abridged, on the precipitation of platina by mercury ; but which 

 show that " the state of oxidizement of the latter metal, as well as 

 the acid in which it is dissolved, produce a considerable modification 

 in the result." It then occurred to him, that " a method of uniting 

 platina and mercury, without the intervention of any other metal, 

 or of any substance except the solvents of these metals, might be ac- 

 complished, as in the case of silver and platina :" and he describes 

 an experiment, which shows that when the mercury is at its minimum 

 of oxidizement in nitric acid, the addition of green sulphate of iron 

 is superfluous. But, on the contrary, if " mercury be raised to its 

 maximum of oxidizement in nitric acid, no precipitation occurs till 

 the green sulphate of iron is added." 



Mr. Chenevix also makes a variety of observations respecting the 

 complicated affinities which take place when the muriates of the 

 above metals are employed. These we shall pass over, and proceed 

 to notice those experiments which form the principal object of this 

 paper. From the first experiment it appears, that if a solution of 

 highly oxidized nitrate of mercury is poured into a mixed solution of 

 platina and green sulphate of iron, a muriate of mercury is formed, 

 and also a metallic precipitate ; the former is retained in solution; 

 the latter weighs more than the original quantity of platina, even 

 after nitric acid has been boiled repeatedly, and in large quanti- 

 ties, upon it. By exposure to heat, he acknowledges that little more, 

 N 



