be artificially produced; for if we pump the air from a receiver there remains the luminiferous ether. Through one of these cavities light could not pass, for there would be nothing to bear it. Sound could not come from it; nothing could be felt in it. It would not have a single one of the conditions necessary to the action of any of our senses. In such a void, in short, nothing whatever could occur. Now, in the words of the writer before quoted—the learned doctor himself nowhere puts it so concisely: "A man inclosed in such a closet could neither see nor be seen; neither hear nor be heard; neither feel nor be felt; neither live nor die, for both life and death are processes which can take place only where there is force, and in empty space no force could exist." Are these the awful conditions (some will ask) under which the friends of the lost are to think of them as existing, and doomed forever to exist?
Baldly and imperfectly as here stated, Dr. Hern's theory, in so far as it professes to be an adequate explanation of "mysterious disappearances," is open to many obvious objections; to fewer as he states it himself in the "spacious volubility" of his book. But even as expounded by its author it does not ex-
