Page:Miss Madelyn Mack Detective.pdf/113

early Greek poets for which I have looked in vain in our modern literature. Ovid's verses on love, for instance, and his whimsical letters to maidens who have fallen early victims to the divine passion—"

"Are you joking or torturing me, Miss Mack?"

Madelyn's face grew suddenly grave.

"I am sorry. Believe me, I beg your pardon! But—it was Ovid who showed me the purpose of the tray of ashes! In one of his most famous verses there is a recipe for sympathetic ink, designed to assist in the writing of discreet love letters, I believe.

"It is astonishingly simple. No mysterious chemicals, no visits to a pharmacist. Instead of ink, you write your letters in—milk! Of course, the words are invisible. Apparently you are leaving no trace on the paper. Rub the sheet with wood ashes, however, and your message is perfectly legible! I don't know where Ovid found the recipe. It has survived, though, for seventeen hundred years. There is only one caution in its use. Make sure that the milk is not skimmed!

"A letter in invisible ink, you will admit, was thoroughly in keeping with the other details of our mystery. The encyclopedia in the library convinced me that I had made no mistake in my recipe—and then I turned to the butler, and my theory