With Cobalt Blue The Name Azure Has Sometimes Been Given To It

: ON THE PRIMARY, BLUE.

Varying exceedingly in quality and colour, the rougher kinds have been

employed by the laundress, and in the making of porcelain, pottery,

stained glass, encaustic tiles, &c.; as well as to cover the yellow

tinge of paper. For this last purpose, however, smalt is not perfectly

adapted, the colour being difficult to lay on uniformly, and the paper

when written on blunting the nibs of pens. Hence it has been superseded

to a great extent by artificial ultramarine, the presence of which may

be detected by the yellow spot which a drop of acid leaves on the paper.



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