1912-13.] The Absorption of Light by Inorganic Salts, No. XI. 161 
in which I have had any success is that of water.'* It has two great 
bands in the infra-red, and by assuming the system represented in the 
diagram below, where M is an oxygen atom with two negative charges, 
and m,m hydrogen atoms, one with a positive charge and the other with 
two positive charges and a negative charge, I obtained 2-32 for the ratio 
of the wave-lengths instead of 2 •00, and 7110 or 1550 for the value of e/m 
instead of 9660, according as I used the first or second band. The result 
is certainly significant. 
I have carefully examined the radiometric results of W. W. Coblentz j- 
in the hope of interpreting some of his infra-red spectra in the same way. 
Some of his spectra, notably sulphur dioxide, carbon dioxide, carbon 
monoxide, and carbon disulphide, looked very promising, giving only one 
or two bands, but the values of pe/m obtained from them were much too 
low. That is, if we suppose the atoms to have each one elementary charge 
M 
m 
TQ- 
Fig. 1. 
of electricity and to be in a state of vibration, the absorption bands should 
be very much more intense than they really are. 
I do not, therefore, regard the prospects of extending further the mathe- 
matical theory of dispersion and absorption as very bright at present. 
The only other worker who has been approaching the subject from the 
same standpoint as myself is Prof. J. Koenigsberger J of Freiburg, Baden. 
He has derived methods for obtaining jpe/m from the values of the 
coefficient of absorption throughout an absorption band, but they are not 
so convenient for calculation as my formula. I did not become aware of 
his methods until within the past year. He finds that Planck’s theory of 
* “The Mechanics of the Water Molecule,” Proc. Roy. Soc ., A, 86, p. 102, 1911. 
t Publications of the Carnegie Institution , Washington , Nos. 35, 64-67, 97-99. 
f “Uber das Yerhalten gebundener und ‘freier’ Electronen gegen elektromagnetische 
Strahlung,” J. Koenigsberger u. K. Kilching, Ann. d. Phys. (4), 28, p. 889, 1909 ; (4), 32, 
p. 843, 1910. 
“ fiber die Bestimmnng der Zahl schwingender Teile in Dampfen, Losungen, leuchtenden 
Gasen,” J. Koenigsberger, Ph. Zs ., 12, p. 1, 1911. 
“fiber die Farbe anorganischer Salze und die Berechnung der schwingenden Teile,” 
Eva von Bahr n. J. Koenigsberger, Heidelberg. Sitzungsber., 1911. 
“ On the Origin of Selective Continuous Absorption of Band and Series Spectra,” 
J. Koenigsberger, Astroph. Jr ., 35, p. 139, 1912. 
VOL. XXXIII. 
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