Abstract
Phase velocity of C.W. transmitted from the four Decca stations the Hokkaido Chain were investigated, by using the decometer readings at 59 points, 40 of which were on board, while the others in land. Although phase velocity are different in various transmitted paths, the seasonal variation in an individual path is comparatively small. In order to obtain the most appropriate hyperboric lattices for practical use, more precise investigations on propagation of waves are desirable.
