Analyses of cosmic spherules with an X-ray microanalyser

With an X-ray microanalyser it has been possible to analyse different layers of cosmic spherules from deep-sea sediments, although the weight of each spherule was less than 10 ^-6 g. A short description of the instrument is given. The spherules consist of iron oxides, with or without a metallic nucleus of iron-nickel-cobalt. Nickel and cobalt are strongly enriched in the nucleus (as much as 50% Ni has been found), which seems to be due to selective oxidation of the iron. Selective oxidation of different elements in steel as investigated with the microanalyser by MOREAU and CAGNET (1957) is discussed in connexion with Prior's "law" concerning chondritic meteorites.