What these volumes might contain Valentine Hawkehurst knew not; and the very fact of his ignorance rendered these books all the more suitable for the purpose of augury. To dip for a sentence into any of these unknown volumes would be a leap in darkness more profound than he could find in the Bible or the "Æneid," where his own foreknowledge of the text might unwittingly influence the oracle. He went over to the recess, bent down, and ran his hand along the backs of the volumes, with his face turned away from the books towards the window.

"The first obstruction that arrests my hand shall determine my choice of the volume," he said to himself.

His hand ran easily along the volumes on the upper shelf—easily along the volumes on the second shelf; and he began to doubt whether this mode of determining his choice could be persisted in. But in its progress along the third and lowest range of volumes, his hand was arrested midway by a book which projected about half an inch beyond its fellows.

He took this book out and carried it to the table, still without looking at it. He opened it, or rather let its leaves fall open of their own accord—still without looking at it; and then, with a strange superstitious fear—mingled in his mind with the natural shame that accompanied his conscious folly—he looked at the page before him. The line on which he fixed his eye was the heading of a letter. It was in larger type than the rest of the page, and it was very plain to him as he stood a little way from the table, looking down at the open book.

The line ran thus:

"ON THE FALLIBILITY OF COPPER GAUZE AS A TEST FOR THE DETECTION OF ARSENIC."

The book was a volume of the Lancet; the date twenty years ago.

"What an oracle!" thought Valentine, with a cynical laugh at his own folly, and some slight sense of relief. In all feeble tamperings with powers invisible there lurks a sense of terror in the weak human heart. He had tempted those invisible ones, and the oracle he only half believed in might have spoken to his confusion and dismay. He was glad to think the oracle meant nothing.

And yet, even in this dry as dust title of a scientific communication from a distinguished toxicologist there was some sinister significance. It was the letter of a great chemist, who demonstrated therein the fallibility of all tests in relation to a certain poison. It was one of those papers which, while they aid the cause of science, may also further the dark processes of the poisoner, by showing him the forces he has to encounter, and the weapons with which he may defend himself from their power. It is needless to dwell here upon the contents of this letter—one of a series on the same subject, or range of subjects. Valentine read it with eager interest. For him it had a terrible importance in its relation to the past and to the present.

"I let the book fall open, and it opened at that letter," he thought to himself. "Will it open there a second time, I wonder?"