For over ten years an expanding collaborative programme of experimental work on the absorption spectra of neutral atomic and simpler molecular gases and vapours, and on similar species “matrix-isolated” in rare-gase solids, has been in progress. The experimental work has centered on use of background continua from the 0.5 and 2.6 GeV synchrotrons in Bonn, - high resolution work being based mainly on the smaller machine. The instrumentation includes - most significantly for the work reported here - a 3-metre Eagle-style vacuum spectrograph equipped with “holographic” gratings of 5,000 – 6,000 1/mm spacing, and usable over the range 200 – 2,000Å.