1030 
PROFESSOR AV. K HARTLEY ON 
Ferro-manganese yielded a very fine spectrum after an exposure varying from 15 
to 30 minutes, better in fact than any compound of that substance. It may thus be 
generally stated that manganese alloys containing iron yield a more distinctive 
spectrum of manganese than any compound containing the same proportion of that 
element. (See the upper spectra on Plate 14.) 
Metallic manganese, deposited on platinum by the electrolysis of a perfectly pure 
solution of the chloride, was heated in the oxyhydrogen flame for half-an-hour and its 
spectrum photographed. 
Pure manganic oxide ■\eas prepared from a solution of potassium permanganate by 
the action of alcohol and a small quantity of sulphurous acid. The precipitated 
oxide, washed and ignited, was heated on a support of kyanite in the flame of 
the oxyhydrogen blowq^ipe for an hour and 20 minutes. It will be seen that as 
there is a considerable difference between 30 and 80 minutes in the exposure, a 
corresponding difference in the width and intensity of the bands common to the 
two spectra obtained from the metal and the oxide may be anticipated. Also bands 
invisible or barely discernible in the spectrum of the metal with 30 minutes’ exposure 
will, it is possible, be clearly defined after an exposure of the oxide for 80 minutes. 
The same spectrum as regards its leading featm-es as that yielded by metallic 
manganese, was obtained by deflagrating a mixture of finely-powdered potassium 
permanganate and lamp-black. 
Manganese. 
Metallic manganese, deposited on platinum by the electrolysis of a perfectly pure 
solution of the chloride, was heated in the oxy-hydrogen flame for half an hour. 
References; F. and T., Fievez and Thalen ; V. and T., Yogel and Thalen; 
L. DE B., Lecocq de Boisbaudean ; K. and R., Kayser and Runge; C., Cornu. 
Description of Spectrum. 
1 
A’ 
A. 
References. 
]\Iore refrano’il4e edge of band, weak . 
17078 
5855 
5855'2, Fe, F. and T. 
Line, doubtfnl. 
17202 
5813 
17242 
5800 
5800, Fe, F, and T., also 
1 
More refrangible edge of very weak band, 
17350 
5764 
L. DE B. 
or a line. 
Afore refrangible edge of very weak band, 
17451 
5730 
Uncertain. 
or a line. 
Afore refrangible edge of A’cry weak band. 
17508 
5712 
Uncertain. 
or a line. 
Edge of band, or a line. 
17568 
5692 
,, ,, and apparently a line . . . 
17786 
5622 
5023-5, Fe, F. and T. 
Strongest part of band. 
17863 
5598 
i Edge of band hazy .. 
i 
17886 
6591 
5591, Fe, F. and T. 
