The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1885-03-07
Correspondence baltimore County Union
SCIENTIFIC MISCELLANY.


Great as are the wonders the microscope reveals,
it will not-as is sometimes supposed-show fly
magnified to the size Of an elephant nor Tea OF
horse-like proportions, for the reason that under
a high power only very small part OF either OF
those creatures can be seen at one time. The size
of the field of view covered by ordinary lenses has
been computed as follows: With power of 20
diameters, about one fourth of an inch with 81
diameters, one-eighth of an inch with 100 diam
eters, sixteenth of an inch; with 800 diane
tiers, one -eightieth of an inch; and with 1000
diameters, one one hundred fftieth of an inch, a
space ordinarily invisible to the naked eye. Even
the smallest creature shown to our unaided vision,
therefore, cannot be seen entire when magnihed
1000 diameters.
AN INTERESTING CELESTIAL VISITOR.
Encke's comet, which travels around the sun in
about three and half years without going beyond
the boundaries of the solar system, and which has
the honor of being the first known comet of short
period, is chiefly remarkable on account of the
retardation of its motion. This has amounted to
about four days since 1919, and is supposed by
some astronomers to prove the existence of a re-
perihelion passage this year is March 9TH, and its
return was first observed Dec. 18th. 1t is visible
only with telescope.
POWERFUL APPARATUS.
The largest electrical influence machine in the
world has just been made for the physical labora-
tory at South Kensington. Its discs are seven
in diameter, of pate-gass three -eighths of an
inch thick, and weigh $50 pounds each. Tested
under unfavorable conditions, the machine has
given a constant stream of sparks fourteen inches
long.
THE EARS CAPACITY.
It has been found by DIR. Lawson TAFT that, as
a rule, the ear in women can perceive higher notes
that is sounds with a greater number of vibra-
tions per second-than the ear in men. The
L II. e. III r.
somewhere between Al 900 and 1000 vibrations.
The ears of most persons seem to be unequally
sensitive to acute sounds, the right ear usually
hearing higher note than the left. To show the
ears range, it may be added that very low notes
of about fifteen vibrations per second may be per-
ceived, but when the vibrations become little
slower they cease to produce the effect of a con-
tinuous sound, and each gives separate impress
sion upon the ear.
EARLY BIRDS.
Prof. Huxley has remarked that while birds
constitute a we'll defined group, nobody mis-
taking the forms included therein, we find the
case to be different when we turn to the ge0logi-
cal record. Fossil forms are found that present
definitions do not embrace, indicating a wider
range of structure, and the existence of types in
termediate between birds and reptiles.
INEQUALITIES OF sEA-LEvEL.
study and comparison of the ocean tempera-
ture records of the Challenger exploring expedi-
ton have shown DR.. James Croll that the surface
of the Atlantic must be lower at the equator than
farther north, the maximum height of the North
Atlantic being reached between the fortieth and
ftieth degrees of latitude. This difference is due
to the difference in the specific gravity of the
water. In the latitude of Hayana the AtIantics
surface must be two and one fourth feet higher
than at the equator, and in that of Chesapeake
Bay the difference is foot greater.
MISCELLANEOUS.
pressure of forty to 100 atmospheres, exerted
during period of fifteen years, has been found
by Quincke to be incapable of forcing pereepti-
BILE quantity of carbonic acid or hydrogen gas
through glass wall one sixteenth of an inch
thick.
On keeping fatty oils several hours at temper
ature of four degrees below zero, Sierra Carpi has
obtained solids of remarkably different degrees
of hardness minute cylinder of iron was only
forced into solidifed olive oil by pressure of
LOO grams, while cotton oil required but %
grams.
The artificial heat of London has been estimated
to be sufficient to raise the temperature of an air
stratum 100 feet thick over the entire city q de-
grees every hour.
Alarge amount of oil exists in the stormy petrol,
and when fat according to Brunnich the inhabi-
tants of the Farce Islands use it lamp, obtain
ing their light from wick drawd through the
birds body.
A collection of skulls from the southern hemis-
phere has been studied in England, the most no
table conclusion reached being that some of the
races of South Africa, Australia and the southern
most part of South America are remarkable for
the smallness of their heads
The oldest geographical society has been gen
orally regarded as that of Paris, but according to
DR.. Ruge that honor belongs to the Cosmographic
Society of Nuremberg 1t was established about
LAO, while the Paris society was not founded
until 1,721. A Swiss geographer estimates that
the worlds geographical societies now contain
$4,000 members.
that a smoky atmosphere is not wholly unmiti-
gated evil, since its carbon and sulphur must alb
sorb many germs of disease, and tend to prevent
the spread of epidemcs.