Abstract
THIS discourse is concerned with certain very minute objects of the rocks—so minute as to be visible only with the aid of the microscope—known to petrologists by the cumbersome name of “pleochroic halos.” Although we shall be occupied mainly in considering quite recent additions to our knowledge of halos, yet, in view of the fact that many of this audience will probably hear of them now for the first time, it is necessary to begin with some elementary remarks.
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Radio-Active Halos 1 . Nature 99, 456–458 (1917). https://doi.org/10.1038/099456a0
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DOI: https://doi.org/10.1038/099456a0
