It seemed, in fact, that the star had been transformed into a planetary nebula, but later the spectrum seems to have lost this peculiar monochromatic character, the nebula line having disappeared and a faint continuous spectrum alone being visible, which is also the case with the star of 1866 since it sank down to the tenth magnitude.
"The Story of the Heavens"
Robert Stawell Ball
Pliny speaks of painters who painted in one or two colors; and, as respects the angelic characters, Milton does so; he is monochromatic.
"Biographical Essays"
Thomas de Quincey
They also were monochromatic; they also, as to the characters of their persons, painted in one color.
"Biographical Essays"
Thomas de Quincey