 It's in a book by Dr. Fergus Wood, a former relief with the East Coast and Geodetic Survey, and then became the National Oceanic and Atmospheric Administration. Anyway, he's a genius and a master meteorologist, oceanographer, and geophysicist. Anyway, this book shows all of my seismic windows, and I didn't run across it until about 1979 after I'd been doing it for five years. So in that book, he described the strongest tidal force,