the hole in the wall which he enlarged on our side.
"No, that is my own improvement on it. You remember once we used a quick-shutter camera with an electric attachment, which moved the shutter on the contact of a person with an object in the room? Well, this camera has that quick shutter. But, in addition, I have adapted to the detectascope an invention by Professor Robert Wood, of Johns Hopkins. He has devised a fish-eye camera that 'sees' over a radius of one hundred and eighty degrees—not only straight in front, but over half a circle, every point in that room.
"You know the refracting power of a drop of water. Since it is a globe, it refracts the light which reaches it from all directions. If it is placed like the lens of a camera, as Dr. Wood tried it, so that one-half of it catches the light, all the light caught will be refracted through it. Fishes, too, have a wide range of vision. Some have eyes that see over half a circle. So the lens gets its name. Ordinary cameras, because of the flatness of their lenses, have a range of only a few degrees, the widest in use, I believe, taking in only ninety-six, or a little more than a quarter of a circle. So, you see, my detectascope has a range almost twice as wide as that of any other."
Though I did not know what he expected to discover and knew that it was useless to ask, the thing seemed very interesting. Craig did not pause, however, to enlarge on the new machine, but gathered up his tools and announced that our next step would be a visit to a lawyer whom the Elmores had retained
