« 657 ) 
found in copper while most of the salts of this metal are paramagnetic 
du Bois and Honda’s paper in which these three metals are classified 
under those whose paramagnetism is invariable or increases with 
the temperature shows that the first assumption is the correct one. 
The behaviour of copper with the present research made us consider 
the other hypothesis a reasonable one. 
One could always assume that the paramagnetism, which, as a 
general rule is ascribed to the metallic manganese, results from the 
presence of its oxides, which are strongly magnetic, or of a small 
quantity of iron. To put this assumption to the proof we prepared very 
pure manganese from Merck’s pure chloride, which had been proved to 
be free from iron. The preparation was accomplished by electrolysing 
the salt between a cathode of distilled mercury and an anode of 
iridium alloyed with 40°/ 0 of rhodium which is not attacked by the 
chloridion. The almagam obtained in this way was separated in a 
stream of pure, dry hydrogen. In this way a grey powder was 
obtained which when compressed in a J glass tube as a mould took 
the shape of a solid rod. A rod prepared in this manner exhibited 
paramagnetism. A glass tube with the powdered manganese was also 
paramagnetic. The same manganese contained in a magnesia boat 
was thereupon fused in an electric resistance furnace and in an 
atmosphere of hydrogen. In this way an ingot was obtained which 
was covered with a light oxidised crust. It was found impossible to 
grind away this crust with quartzpowder, since the metal was of 
the same hardness as quartz. Emery could not be used as it is 
magnetic. The impure crust was therefore turned off with a diamond 
tool, and a small cylinder of pure substance was obtained. 
This cylinder was found to be ferromagnetic. Fig. 2 PI. I gives 
the hysteresis curve for this substance. The maximum value of the 
specific magnetization is 100 times weaker than that of iron, and 
the coercive field is 670 gauss, that is to say, 10 times as strong 
as the coercive field of steel which is used for the preparation of 
good permanent magnets. This peculiar substance seems moreover to 
have striking magneto-crystalline properties. The rod was strongly 
attracted between the poles of a magnet and placed itself perpendi¬ 
cular to the field. 
Manganese of the same degree of purity can therefore occur in 
two states: paramagnetic and ferromagnetic. Gebhardt’s experiments 
give a susceptibility five times greater than that observed by du Bois. 
If Gebhardt’s powder was not impure or oxidised, it is thus possible 
that there are two paramagnetic states. 
“) Seckelson, Wied. Aim. LXVII, p. 37, 1399- 
