when is a black cat red?

From a Scottish book of Irish wit and anecdote:

When Barnum was in San Francisco, he advertised for a cherry-coloured cat. An Irishman answered the advertisement, and offered to bring him a fine cherry-coloured pussy for two dollars and a half. Barnum was so delighted that he sent the man the money at once, in order to hold him to his bargain. But his delight changed to unmitigated disgust when the Irishman came and jerked a wall-eyed, sickly-looking black cat out of the bag, and told him that its name was Billy, and that it was very fond of fish. "What d'ye mean by bringing me this thing?" yelled Barnum. "Didn't you say you had a cherry-coloured cat?" "I did that, Mr. Barnum," said the Irishman, "and didn't Oi bring ye wan? Didn't ye iver ate black cherries, asthore (before - curator)?" The great showman never advertised for a cherry-coloured cat again.

(I think Barnum was looking for a dark orange cat.)  William Harvey, Irish life and humour, in anecdote and story (1906: Eneas McKay), p. 75