Uranium Red

: ON THE PRIMARY, RED.

By treating the yellow sulphite of uranium with a prolonged current of

sulphuretted hydrogen, and saturating gradually with ammonia, a red

finally results. This colour is insoluble in water, and it has the

objection of remaining partially suspended for an almost indefinite

time, colouring the liquid light red. The product is brighter and more

beautiful while moist; when dried and powdered, its tone--slightly

approaching vermilion--is duller. The colour may be obtained of several

degrees of brilliancy, but, apart from the question of expense, it would

be inadmissible in oil, the red gradually altering by contact therewith.

The most persistent tint at length resembles burnt Sienna.



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