And the discoverer of the X rays thus stated as calmly his ignorance
of their essence as has everybody else who has written on the
phenomena thus far.

"Having discovered the existence of a new kind of rays, I of course
began to investigate what they would do." He took up a series of
cabinet-sized photographs. "It soon appeared from tests that the rays
had penetrative power to a degree hitherto unknown. They penetrated
paper, wood, and cloth with ease; and the thickness of the substance
made no perceptible difference, within reasonable limits." He showed
photographs of a box of laboratory weights of platinum, aluminium, and
brass, they and the brass hinges all having been photographed from a
closed box, without any indication of the box. Also a photograph of
a coil of fine wire, wound on a wooden spool, the wire having been
photographed, and the wood omitted. "The rays," he continued, "passed
through all the metals tested, with a facility varying, roughly
speaking, with the density of the metal. These phenomena I have
discussed carefully in my report to the Würzburg society, and you will
find all the technical results therein stated." He showed a photograph
of a small sheet of zinc. This was composed of smaller plates
soldered laterally with solders of different metallic proportions. The
differing lines of shadow, caused by the difference in the solders,
were visible evidence that a new means of detecting flaws and chemical
variations in metals had been found. A photograph of a compass showed
the needle and dial taken through the closed brass cover. The markings
of the dial were in red metallic paint, and thus interfered with the
rays, and were reproduced. "Since the rays had this great penetrative
power, it seemed natural that they should penetrate flesh, and so it
proved in photographing the hand, as I showed you."