Put into a wine-glass of water, a few drops of prussiate of potash; and
into a second glass of water, a little weak solution of sulphate of
iron in water: pour the colourless mixtures together into a tumbler,
and they will be immediately changed to a bright deep blue colour.
Or, mix the solution of prussiate of potash with that of nitrate of
bismuth, and a yellow will be the product.
Or, mix the solution of prussiate of potash with that of sulphate of
copper, and the mixture will be of a reddish brown colour.