Evening star. [volume] (Washington, D.C.) 1854-1972, 1911-04-02
BY F. v. COLLINS

b
if they were composed of sulphur, as has
been generally surmised, they would show
intensely black. This new camera eve, ap-
piled to the telescope, offers the latest aid
to the astronomer in his fascinating search
of the heavens.
In a Murder Trial
EVEN before it had been adapted exclu-
- sively, by means of special lens construc-
ton and combination, to the reception of
the invisible ultraviolet rays, the camera
eye owing to its peculiar sensitiveness to
this light, has played a strikingly dramatic
role on various occasions. One of these oc-
Cured few years ago in Lausanne, Switzer-
land.
1t appears that handkerchief formed
an exhibit at a murder trial, and was
regarded as crucial bit of evidence. The
closest inspection failed to reveal stain on
the Immediately white cloth, even with the
aid of powerful microscope. But it &C.
CURED to professor of Lausanne University
to photograph the handkerchief when the
image obtained clearly disclosed the pres
ence of great splotches, or rather of what
had been such, showing ghostfke in the
carefully washed fabric. The photograph
proved the turning point of the trial. and
the result was conviction.
Blood, as was scientifically explained at
the time, happens to be one of the SUBJ
stances that absorb ultraviolet rays, and
when any of these substances have found
their way to receptive surface no amount
OF erasing or cleansing can hide its presence
from the camera eye. When the latter is
equipped to utilize only this invisible light,
the result is much more marked. Should
the neatest erasure be made in writing done
with substances specially absorbent of the
rays, the ultraviolet photograph would show
the traces of the erasure as plainly as the
writing itself.
A striking example of the detective power
of the camera eye in this regard happened
not long ago in France, where the signature
to an old and valuable document had en-
tirely disappeared. The inheritance of a
large estate devolved upon the missing sig
nature, and the evident heir had to wait
many years before the camera eye finally re-
vealed its existence and gave to him his long
withheld property. Even an ordinary cam
era lens has proved, on numerous occasions,
a successful detector of forgery.
Peculiar Place for Advertising
THE retention Of ultraviolet rays by
printers ink may sometimes lead to
queer results. On one occasion man re-
ceived a boxful of Photographic plates from
friend for development. He succeeded in
evolving prints which. generally speaking.
were excellent; but was somewhat surprised
to perceive business advertisements in po-
sitions where even the most persistent and
ingenious advertising artist would find it
difficult to place them. Not only were rocks
and trees embellished with the words, Use
So & Sos Baking Powder" advertisements
of soap, etc., but these and similar legends
were inscribed upon bodies of water and in
the sky, as well as upon different parts of
the persons appearing in the groups. 1t
seems that, in packing up the plates, the
sender had placed pieces of printed paper
between them, and on the journey the ink
had affected the sensitive surfaces, screened
effectively from ordinary light as they
were.
Professor Sylvanus Thompson, in a lee
ture delivered at the Royal Institution of
Great Britain not long ago, gave striking
demonstration of the Photographic action
of ultraviolet rays. On board was large
sheet of apparently plain white paper. A
photographer then set up his camera and took
a photograph of the paper. Upon develop
ment of the photograph, it was seen that
there was a bold inscription upon the appar-
emily blank surface, which had been written
with colorless chemical absorbent of ultra
violet rays, which, being invisible to sight,