Tensas gazette., 1910-06-03
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new WONDERS
OF THE
MICROSCOPE
By Prof. E. S. Crew.

Some people can hear the twitter
ing of the bats at evening, and some
there are for whose ears these sounds
are too shrill. 1t is not unlikely that
there are sounds in Nature toe shrill
for any human being to hear though
perhaps insects may hear them. The
harlequin fly, for example, has a hear.
ing apparatus which enables him to
distinguish the beating of the females
wings.
Just as there are sound waves
which are too small and vibrate too
quickly to make themselves heard by
the human ear, so there are light
waves which are too minute to be
perceived by the human eye. In
other words, We might say that there
were some kinds OF light too piercing
to be seen.
But what the eye cannot See there
are instruments which will record,
and the Photographic plate can see
light which man can not. Many uses
have been made Of that. Some OF
the wonderful spiral nebulae Of the
sky have photographed themselves on
the plate by their own light, and so
have revealed themselves as man
never hoped to see them. But that 10
not all. The Photographic plate which
thus has enabled man to see the i'm.
n.rnsely great may help him in the
future to see the incredibly small. 1t
will render him the same kind OF
service in surveying the thingS re.
vealed by the microscope that It has
done In looking at the field Of the
telescopHit will make them clearer,
and 1t will show their structure.
There are certain limits to the pow.
ers OF the microscope. We shall
never he able to see molecules. for
example, ard perhaps one may try to
explain why. It is because molecules
are much smaller than the wave.
lengths OF light. What does that
mean? Well, turn the letter IN" up
side down, and regard 1t as two waves
OF lcug line of them. The distance
between the legs Of the upturned IN"
is the wave-length Of these waves.
Now, suppose these waves to be
ripping against the sides Of tum-
bier of water You can make them
do It by flicking the sides Of the
glass, and you will see that after the
waves have reached the sides Of their
little pond OF water they are reflected.
They would be reflected II they struck
against any object bigger than them.
selves-that is, bigger than the wave
length between the crests. But sup
pose the objects were smaller than
this wave-length. Then, evidently. It
could not reflect them. They would
flow around it without being reflected.
That is what happens when light
waves strike an object. The object
reflects the waves, and, as we say.
We see 1t in consequence. II the
object were smaller than the waves
it would not reflect them, and We
could neither see them nor 1t. That
is why there will always be some
objects which the eye can never see
in the microscope by reflected light.
But there two ways OF getting
around the dificulty-partly. One Is
to make the object visible by light
which shoots athwart it-just as q
shaft OF sunlight lights up the notes
in a sunbeam We shall not see the
structure OF tie notes by this means,
bu. we are able in a Siedentopf mi
croscope to perceive the existence OF
particles which have hitherto been be.
lieved to be beyond the microscopes
powers, and have been called ultra.
microscopic" We can see particles
in this way which are getting near
the size OF molecules.
There is tne other way: That is to
male 'be waves Of light smaller; or,
rather. 70 use smaller waves OF light
in our microscope, SO that smaller OBJ
jects than before can reflect them.
Yes. the reader may urge, but you
Just now told us that IL the waves
of light were too small the eye could
rot gee them. So I did, but l also
added that the Photographic plate
could see smaller waves than our
eyes. Consequently, in the micro
scopes of the future the microscopist
may use light OF the kind which is
invisible to human eyes-the ultra
violet rays-and let the Photographic
plate do the seeing for him. He will
thus be able to photograph objects
no ~
The great advantage will be not
that he will be able to perceive the
existence OF small particles. but that
he will be able to see what their
structure is like. It's no good to him
to magnify II detail is lost in the
process. That is the advantage OF
the wonderful photographs by DR..
Jean Comandon of blood particles.
The details are so marvellously clear.
One Of them shows the micro-organ-
isms OF the disease known as "spiro-
chaetosis," invading the blood cor
puscles OF hen. Spirochaetosis az
fiicts the fowls of North Africa and
the Soudan; and some splrochaetes
Of the method employed by DR.. Com
andon is that he can take a number
OF photographs rapidly, so as to show
the corpuscles and their invaders and
enemies in actual movement by a sort
OF cinematographic method.-New
York American.
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