Coastal Refraction of Wireless Waves

DR. SMITH ROSE, in his letter on this subject in NATURE of September 19, has directed attention to the striking discrepancy between theory and experience in the matter of coastal refraction of wireless waves. It may be of interest to point out that the conclusion, to which he is led from Zenneck's analysis, that waves travel with a greater effective velocity the lower the conductivity of the surface, though contrary, I believe, to what is now generally accepted, is supported by quite simple reasoning.