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REPORT on three samples of VIOLET POWDER received from Mr. W. H. POWER,
April 4, 1878.
All the powders were of a very pale yellowish colour, and rather more
gritty to the touch than ordinary violet powder; they were also
appreciably heavier, bulk for bulk. Taking the weight of a given bulk of
ordinary violet powder as 1, the same bulk of these powders would weigh
about 1.25. Under the microscope they are shown to consist of potatoe
starch mixed with a very considerable proportion of crystalline matter,
among which regular octahedra (arsenious acid) can be distinguished. On
burning they evolve a very powerful arsenical odour.