112 



J. E. MAYER, ESQ. ON THE WATER 



give the mode of preparation. This is as follows ; and the 

 description of the process, with the information in the 

 note* given below, will enable any one to manufacture the 

 compounds under consideration. 



Process. 



To obtain artificially Magnetic Oxide of Iron, having the 

 Formulae *3 °i> such quantity of the green Proto Sulphate of 

 Iron as will afford the required quantity of Oxide being 

 taken, the crystals are to be dissolved in pure water ; two- 

 thirds of the solution thus formed is to be poured into a 

 second vessel, and to this portion, which is to be boiled, 

 Nitric acid is to be added till brown vapours are no longer 

 given off. The Iron contained in this portion will now be 

 in tlie form of Sesqui Oxide, while in the one-third, which 

 has not been boiled, the Iron remains in the form of Prot- 

 oxide. The two solutions are to be mixed together ; 

 the mixed solutions are then precipitated by the Volatile 



* Every equivalent, or 139 grs., of the crystalised green Sulphate of Iron 

 contains 36 grs. of the Protoxide of Iron ; therefore 1 lb. Avoidupois, or 

 7,000 grs, will contain x = 1813 grs. or 4 oz. 65 grs. of the Protoxide, 

 and any other quantity in proportion ; but it is not the Protoxide of Iron 

 that is wanted ; it is the magnetic oxides, of which there are two, — Now, to 

 understand how these oxides are formed, as well as the reasons for the 

 process here given, it will be advantageous to set down in order the various 

 oxides of Iron with their appellations and Formulae, it being premised that 

 Fe stands for Ferrum, Iron, and 0 for Oxgyen. 



Protoxide Fe. 0. : Sesqui Oxide F % g' 



These Formulae convey, in short, the important information that the 



1 Pp. 0. Protoxide of Iron is composed of one combining quantity of Iron, 

 Pe O. and one combining quanti ty of Oxygen ; and that the Sesqui Oxide 



2 3 is composed of two combining quantities of Iron, and three combin- 

 ji^To ing quantities of Oxygen. This being understood, the composition 

 '3 4 of the magnetic Oxides will be at once evident, their respective 



2 (FeToT) Formulae being F g' °* and ^ g" since it is patent to every one* 

 Pe- O. that one atom of the Protoxide and one of Sesqui Oxide, when 



^ 3 united, equal the first magnetic Oxide, and iu like manner it is 

 plain that two atoms of Protoxide, and one atom of Sesqui Oxide, 

 4 5 w ^ en united, equal the second magnetic Oxide. 



The above composition having been clearly demonstrated by repeated and 

 careful analysis, they suggested the artificial process, of which the dominant 

 conditions are, that the protoxide and peroxide should be brought together 

 in the particular proportions shewn, and in a recent state, How this is 

 effected will be seen in the text of this paper. 



