FOR some ten years, at the Zi Ka Wei Observatory, in Shanghai, China, we have been using, with exceptional success, a new technique in our weather forecasting. This method is based on an as yet unexplained correlation between the usual ionosphere echoes (E, F and F 2) and the future movement or behaviour of the three main air masses, which make the weather all over the world: polar, maritime and tropical, or equatorial, as some people call it. Our results have already been published in the Bulletin of the Meteorological Society of America, in 1946, and in a paper sent to the last Pacific Science Congress held in New Zealand last February.