74 Scientific American, December 202150, 100 & 150 YEARS AGO
INNOVATION AND DISCOVERY AS CHRONICLED IN Scientific AmericAn
Compiled by Mark FischettiSCIENTIfIC AmERICAN ONLINE
FIND ORIGINAL ARTICLES AND IMAGES IN
THE Scientific AmericAn ARCHIVES AT
scientificamerican.com/magazine/saScientific American,Vol. 225, No. 6; December 19711971
How Birds
Breathe
“A bird’s respiratory system can
deliver enough oxygen for the ani-
mal to fly at altitude. How do the
birds do it? The bones of birds con-
tain air. This is true not only of the
larger bones but also often of the
smaller ones and of the skull bones.
Birds have two lungs that are con-
nected to the outside by the tra-
chea, but in addition they are con-
nected to several large, thin-walled
air sacs that fill much of the chest
and the abdominal cavity. The sacs
are connected to the air spaces in
the bones. In this way it becomes
apparent that the blood, as it is
about to leave the lungs, can take
up oxygen from air that has the
highest oxygen concentration
available anywhere in the system.”
1921
Needed: Teachers
Who Experiment
“What must America do to estab-
lish itself as the leader among
nations for world trade? The prin-
cipal essential is a body of trained
investigators. Nowadays what most
of us are doing depends upon some
phenomenon or property of matter
unknown a century ago, which has
now become a pillar of civilization.
We have splendid laboratories. We
have a wealth of materials. We
have abundant money. But we
need more college professors who
are not content to give their pupils
merely the results of scientists of
the past, but who are themselves
experimenting to learn new scien-
tific truths, and who encourage
their pupils to experiment.
—W. R. Whitney, Director, General
Electric Research Laboratory”
Smoke, Not Fire
“A new form of fire alarm has been
invented in England. It depends
upon the presence of smoke and
is not affected by temperature
changes, which usually are the
chief factors in the operation
of most fire alarms. The smoke
learned. The trustees have resolved
to place the elements of physical
science at the very beginning of the
course. They do not propose to wait
until the pupil, by droning over dry
facts and abstract principles, has
acquired a disgust for every branch
of knowledge. They think it wiser
to pursue the natural method, and
begin when the mind is anxiously
inquiring into the cause of things.”Dehydrated Meat
“At the meeting of the Lyceum of
Natural History, Dr. H. Endemann
gave an account of a process in vent-
ed by himself. About 100 pounds
of meat are placed in a suitable
chimney, and air, heated to 140
degrees Fahrenheit, is drawn by
an exhauster through it until it is
entirely dry. The meat is subse-
quently ground into powder, and
will keep in ordinary paper pack-
ages. It can also be compressed
into hard cakes. Four to five
ounces of the dry powder repre-
sents one pound of meat. Scat-
tered upon bread, its flavor is
excellent and preferable to that
of raw meat. It has an agreeable
aromatic odor. And, as all of the
albumen and fibrin are present,
all of the nutritious properties of
the flesh are retained.”detector consists of a metal cylin-
der some eight inches long and
two inches in diameter, open at
each end, so that air can circulate
freely, and containing two rectan-
gular metallic capsules, one of
which is considerably larger than
the other. The smoke on the cap-
sules causes one to bend more
than the other, completing an elec-
trical circuit, and a large electric
bell or other alarm signal may be
operated. The advantage is that its
action is more rapid and reliable.
In many fires dense smoke would
be produced before any material
rise in temperature occurred.”1871
Also Needed:
Practical Education
“The custom of learning everything
by rote, and reciting like a parrot,
has become so embedded in our
system of education that it seems
almost impossible to find any
explosive sufficiently active to blow
it up. It is probable that we must
look to the West. At the University
of Iowa, instead of teaching
physics, chemistry, geology and
astronomy by oral recitations
and un illustrated lectures, they
have established laboratories and
workshops where practical things
can be practically1971192118711971: Optical illusions
like this one by
M. C. Escher exploit
a phenomenon that
challenges the brain’s
representational
system: figure-
ground reversal,
in which one con-
tour can be part
of two shapes.
The brain has
trouble deter-
mining which
shape should be
regarded as the
figure and which
as the ground.
Do you see
white angels or
black devils? — M.F.DECEMBER