Weather balloon Weather balloon A weather or sounding balloon is a balloon (specifically a type of high-altitude balloon) that carries instruments aloft to send back information on atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde. To obtain wind data, they can be tracked by radar, radio direction finding, or navigation systems (such as the satellite-based Global Positioning System, GPS). Balloons meant to stay at a constant altitude for long periods of time are known as transosondes. Weather balloons that do not carry an instrument pack are used to determine upper-level winds and
What Is History? of things in the world, in a 1970 article entitled "Marxism and History", Carr argued that with the exception of the Mexican Revolution, every revolution in the last sixty-odd years had been led by Marxists. The other revolutions Carr counted were the revolutions in Cuba, China, Russia, and a half-revolution in Vietnam (presumably a reference to the then on-going Vietnam War). This together with what Carr saw as the miserable condition of the Third World, which comprised most of the world led Carr to argue that Marxism had the greatest appeal in the Third World, and was the most likely