The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913, 1896-08-21
X RAYS TEST DIAMONDS,
Roentgen's Discovery Used to
Expose Faulty Setting of
Bones.
Many Applications of Photography
Explained by Professor Van
der Naillen.

The discovery, the history and the prac-
teal uses of the K ray formed the SUBJ
iect of an interesting popular lecture de-
livered in Golden Gate Hall Wednesday by
Professor A. Van der Naillen of this City,
who recently returned from Paris with
apparatus and fine photograph plates IL
Illustrative of the most recent accomplish
ments with the Roentgen ray.
By the aid of the stereopticon enlarged
pictures of photographs were thrown upon
big screen. There was wild duck that
had been shot near Paris. Merely the out
line of the skeleton showed, but all about
were little back dots where the shot was
imbedded in the flesh or lodged near the
bones. Another photograph showed a
compound fracture in the bones of mans
leg. That man had paid to have the bones
properly set, and after the job was done ne
walked like horse with the strlnghalt.
He went to Paris, had Photograph taken
of the bones, and Their started for home
confident of winning suit against the
doctor simply by the evidence of the un-
skillful work shown by the Photograph.
There was very rich lady of Paris who
suspected that her jeweler had changed
the stones" in her priceless diamond neck
lace. She mentioned her fears to a ply.
stefan who had an x ray apparatus. He
took radiograph OF the necklace and de-
veloped the plate while she waited. Pure
carbon, pure hydrogen, pure oxygen and
pure nitrogen are generally transparent
to the Roentgen ray. Only the settings of
the necklace showed in the Photograph, for
wherever there was diamond the pure
carbon offered no obstruction to the rays
and only white spots resulted. But three
of the large pendants near the front of the
elaborate and many gemmed necklace
came out as dark spots. The owner of the
necklace brushed away a tear and prepared
to go on the warpath.
There was another case of man who
had been shot in the foot. He paid his
money to a surgeon anG had the shot
picked out. but his foot grew worse. He
had Photograph made and it showed that
the surgeon had taken out all the shot ex-
cept about twenty more deeply imbedded
than the others.
Several kinds of glass tubes may be used
in the production of the Roentgen ray.
The common pear shaped tube has small
platinum plate inside the small end, with
its surface facing the big end. An electric
wire is sealed into the small END of the
tube, near the platinum plate, which is the
negative pole, cathode, or source of the
cathode rays. The aurode or positive
pole. is at the side of the tube, another
wire being sealed in AT that point.
The interior is partial vacuum. Dur.
ing the passage of an electric current rays
pass from the cathode on through the big
end of the tube and out into the air. Thew
are the x or Roentgen rays, but the
cathode rays are not Roentgen rays. The
constant attack of these straight rays upon
the same spot at the big end of the pear
shaped tube in time destroys the glass. A
professor of Mississippi Valley college,
with whom the lecturer was returning to
America, exhibited with pride the fine
pear-shaped tubes he had purchased in
Europe for his laboratory. Every one of
them proved to be badly damaged at the
big end from use.
A little cigarette-shaped tube, named
after its maker the Collardeau tube, is
very successful in the production of sharp
images OF small size, but it cannot be used
for large objects. TIE Newton London
tube Is the one now in most general use in
the hospitals and scientific institutions of
Paris.
The center of the human eye is not
transparent to the rays and that is why
they probably cannot he seen. all other
parts of the body except the bones are
transparent; but the bones com posed as
they are of various metallic salts offer an
obstacle to the x rays.
The lecture was illustrated throughout
by electric discharges through tubes. by
pictures and by horoscope in opera
ton, the spectators seeing plainly the
greenish cathode rays through many
thicknesses of boards interposed between
the tube and the darkened room.