FIG. 1. Isolated Ir and Os lamellae MNHN* [*See explanations of abbreviations on p. 394]. Hand mt. (a) General view of isolated iridium and osmium lamellae, threads and blades. SEM(SM). 1400 µm. (b) Dendrite-like parallel stems of Os-Ru iridium. SEM(SM). 450 µm. (c) Stem of Os-Pt-iridium with split-off lamellae. SEM(SM). 450 µm. (d) Hollow Ir-Os foils with crystalline outlines. SEM(SM). 1200 µm. (e) Leaf and blade of Ir-osmium. SEM(SM). 600 µm. (f) Group of partly split-off, Ir-Ru-Os blades. The dirt particles on the surfaces are mixed Ir-, Os- and Pt-chlorocompounds. SEM(BS). 160 µm.