A typical national meteorological service comprises a central station or institute, usually, but not always, situated at the national capital, and a network or “réseau” of subordinate stations, which are sometimes classified, according to the extent of their observations, as stations of the first, second, and third order. They may also be classified, from another point of view, as telegraphic and nontelegraphic stations. The former provide telegraphic reports of their observations, which serve as the foundation for forecasts, while the latter are maintained chiefly for the purposes of climatology. In some countries--notably in the United States--there are additional classes of stations engaged in particular lines of work; these include storm-warning stations, river stations (which report river stages and rainfall in the river basins), stations for agricultural meteorology, etc. Several of the great maritime nations collect reports from vessels on the high seas, including a small percentage of wireless reports. A number of the national meteorological services carry on work in other branches of geophysics, such as seismology and terrestrial magnetism. The United States Weather Bureau is an exception to the rule that, apart from the central offices and a few special stations and large observatories, meteorological stations are not generally manned by professional meteorologists, nor are the observers paid specifically for their meteorological work, though in a great many cases they are public functionaries who are expected to take meteorological observations in addition to their other duties. In this country there are about 200 stations at which the observers, of whom there are from one to a dozen or more at each station, devote all their time to the work of the stations and are salaried employees of the Weather Bureau, and there are several hundred minor stations manned by part-time paid employees. But even in the United States the great majority of the meteorological stations are operated by unpaid observers. There are about 4,500 of these so-called “cooperative stations,” which provide the bulk of the climatic statistics of the country. Some of the leading meteorological services of the world, and the places at which their central offices are located, are as follows: United States Weather Bureau (Washington), Meteorological Service of Canada (Toronto), Meteorological Office (London), Office National Météorologique (Paris), Reale Ufficio Centrale di Meteorologia e Geodinamica (Rome), Zentralanstalt für Meteorologie und Geodynamik (Vienna), Indian Meteorological Department (Simla), Central Meteorological Observatory (Tokyo), Commonwealth Bureau of Meteorology (Melbourne), Oficina Meteorológica Argentina (Buenos Aires).