accompanying reproduction of this picture, all the objects are
photographed with remarkable distinctness, the leather case of the
eye-glasses being almost transparent, the wood of the handles of the
awl and saw being a little less so, while the glass in the eye-glasses
is less transparent than either. In the case of the awl and the saw,
the iron stem of the tool shows plainly inside the wooden handle. This
photograph is similar to a dozen that have been taken by Professor
Wright with equal success. The exposure here was fifty-five minutes.

A more remarkable picture is one taken in the same way, but with a
somewhat longer exposure--of a rabbit laid upon the ebonite plate, and
so successfully pierced with the Röntgen rays that not only the bones
of the body show plainly, but also the six grains of shot with which
the animal was killed. The bones of the fore legs show with beautiful
distinctness inside the shadowy flesh, while a closer inspection makes
visible the ribs, the cartilages of the ear, and a lighter region in
the centre of the body, which marks the location of the heart.

Like most experimenters, Professor Wright has taken numerous shadow
pictures of the human hand, showing the bones within, and he has made
a great number of experiments in photographing various metals and
different varieties of quartz and glass, with a view to studying
characteristic differences in the shadows produced. A photograph
of the latter sort is reproduced on page 401. Aluminium shows a
remarkable degree of transparency to the Röntgen rays; so much so that
Professor Wright was able to photograph a medal of this metal, showing
in the same picture the designs and lettering on both sides of the
medal, presented simultaneously in superimposed images. The denser
metals, however, give in the main black shadows, which offer little
opportunity of distinguishing between them.