The Ariel V Sky Survey Instrument and new observations of the Milky Way.

The Ariel V Sky Survey Instrument is described, and preliminary results are given from an extended observation of the Milky Way in November 1974. A substantial number of new, mostly faint, sources are found, due mainly to the higher mean sensitivity of this survey compared with that reported in the 3U catalogue. Source confusion in these single-scan data restricts the number of unambiguous new sources to 16 at this stage. The location and intensity of these sources are listed, and details are also given of 17 3U and MX sources which have shown a marked reduction in X-ray intensity since 1971-72.