An interesting application of electron diffraction

SILICOSIS develops rather quickly in rabbits exposed to air containing moderate concentrations of quartz particles finer than about 5 × 10^–4 cm, but is completely prevented if aluminum powder is also present in the air to the extent of about one per cent by weight of the quartz powder. This protective action of aluminum powder was discovered at the McIntyre-Porcupine Mines, and has been studied experimentally by Denny, Robson and Irwin.¹