The Electromagnetic Spectrum of Water

R. Weichmann. Ein Banden-Absorptionsspektrum des Wassers bei Wellenlängen von mehreren Dezimetern. Phys. Zeitschr. 22, p. 535, 1922.

In view of the discrepancies existing among the results obtained by various observers for the dispersion of water in the region of Hertzian waves, the author (at the suggestion of Mie) investigated the behavior of the refractive index and the absorption of water in the wavelength range from 65 cm to 27 cm. The measurements were made by the method of waves in parallel wires. The waves were excited by a spark vibrator constructed according to Ruhkorff. The arrangement of the wires was vertical, owing to which the waves from the air passed directly into the water. The author succeeded in making the operation of the apparatus so reliable that, in recording resonance curves, he could make 20 readings over a length of 1 mm.

In the measurements, a whole series of resonance curves was recorded, from which the positions of the nodes and the decrements were determined. The refractive index and the absorption were calculated in the usual manner from the wavelengths in air and in water and from the increase of the decrement with the depth of penetration of the waves into the water. The curves presented show the course of the optical properties obtained by the author. The refractive indices are reduced to a temperature of 17° C. The absorption index represents the difference between the index calculated from the observations and the absorption caused by the conductivity of the water.

K. Teodorovich.