Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1873-05-29
COMPARATIVE VEI.oCITIES.
BY F. r. GOULDING.

from the march of an army, is fairly stat
ed at twent., miles day, two miles per
hour, and three feet per second The
slow pace of the OK, and the still slower
OF the tortoise and the snail, whatsoever
they may teach Of the wonders to be ac-
compllshed by perseverance, have little
the aspect of romance We let them
| pass.
| The slowest motion in Nature, of which
| the naked eye can take cOgniZance, is that
OF star as it passes over a small move
| less twlg, while the watcher rests his head
against support The star, we mean "a
hXed star, can never be magnified by the
most powerful telescope to be more than
point OF light, and we might reasonably
expect that in passing the twig it would
De suddenly and wholly quenched on one
side, and as suddenly appear in full glory
on the other. But this is not so; its fad
ing occupies a number of seconds, prOba-
bly, because the pupil of the Watchers eye
is broad enough to graduate its light into
a kind of penumbra.
But there are motions in Nature too
slow to be perceived except after lapse
OF time, though we are certain of them as
| we are OF the march of an army-the
growth OF a plant, for instance; that is,
| the increase OF distance between its root
and the terminal bud. True farmers tell
us that they can sometimes hear their corn
| gr01o, for that, in rich bottom, after a
! shower, in growing weather, the shuck
will creak audibly Of still might, as sit
overlapping parts give way to the increas-
| ing ear. But who yet, unless it be whilom
Jack, of moon-climbing memory, ever
protessed to see the growth Of any thing,
even of the most rampageous vines?
| Slow as these motions are, however,
they are rapid in comparison with others,
which are familiar enough to us all,
| though few persons may have ever had
| the curiosity to calculate their rate. We
cut down giant of the forest and meas
rre its parts. We find it to be three feet
in diameter, and one hundred and fifty
feet in length, from the earth to its top
most twig. On counting its concentric
rings, each one of which required year
for its deposition, we learn that it is three
hundred and sixty years old. These fig
| Uues enable us to determine that the
| growth Of the tree upward has been at the
average rate of five inches a year-a low
rate of velocity, truly! But what shall we
say OF that other velocity, represented by
| the increase of size from the centre of the
| trunk outward? Eighteen inches in three
| hundred and sixty years is at the rate OF
one-twentieth Of an inch in one year or
Ia = Of an inch day, or i. of an inch
an hour.
| Slow as these rates of motion are, they
are as truly velOcit1es-however they may
seem rather to be t0rdities-as the flight
OF arrows, or as the flashing of sunbeams,
| for all yelOcitles are comparative.
Let us now exchange the microscope
for the telescope; in other words, turn
from the lower to the higher velocities
| The ordinary rate Of human travel on
| foot is estimated at twenty miles day.
| But men have not been content with this
snails pace. They first increased their
| speed by the use Of horsepower, which
| gave them an average rate of thirty or
forty miles day. Then they devised
steam power, the average locomotive rate
OF which no one as yet is able to specify.
Already the newspapers have announced
| In large capitals, the astounding fact
| "1r0und the e0rth IN serenty-f01tr daysi" a
| feat which, only a few years since, required
tent0ld the time. Enormous, however, as
this rate Of travel seems to be, when com
| pared in the aggregate with former rates,
| it will be shOrn of much of its apparent
| glory when small portions Of the average
are compared with other well-knOwn
rates; for twenty five thousand miles
| divided into seventy four parts, gives the
average of not quite three hundred and
| forty miles day, or fourteen miles per
hour. This rate was not only attained, but
even exceeded, by many a juvenile savage
| of the Pacific islands, who would learn to
| balance himself on the forward declivitv
| of an ocean bi1lOw, and ride his wild
| horse shOreWard until lodged upon the
sands. What is the speed fthcse pillows
has probably never been estimated, but
| those in mid-Occan have been known to
| Outrun the storms that raised them, and
| to have attained a velocity of forty or more
miles the hour. The rate of travel. indi-
| Gated by the average OF Round the world
| in seventy-fOur days. is far from being
| the highest attained in travelling Forty
miles per hour, equivalent to about one
| thousand miles a day is not uncommon,
| although, if any one will look out Of the
| car-windOw at the rugged sides of q rail
road-cut, while travelling past them at this
rate, he will be apt to feel his blood curdle
at the thought Of possible crash Yet
even forty miles an hour is by no means
the maximum. Twenty years ago, express
! trains on some Of the best constructed En-
| glish railways were run at the fearful
| speed of q mile minute, and, on a special
| occasion, when sudden emergency de
| manded it, a locomotive and its tender
were reported to have been forced up to
nearly one hundred miles an hour.
We turn from this fierce rate, 50 pain
| fully suggestive of accident, to another
which is far greater, yet gentle and pleas
ant. Any one who will watch the play of
| a wOOdman's axe at the distance Of a
| quarter of q mile, will be amused, no mat
| ter how often it has been witnessed, to
note the difference in time between the
fall of the axe and the sound of the blow
reported to the ear At that distance the
stroke is heard while the axe is lifted in
the air. ready for the succeeding blow. a
careful measurement of the velocity of
sound shows that, although it varies much
with varying circumstances, 1t travels usu-
| ally at the rate of about five miles a min
ute This speed is oftentimes made visi-
| bic in the flight of a cannOn-ball; for
although the initial velocity of the ball is
so much greater than of sound that per
sons killed within the range of mile are
usually struck before the report could be
| heard, vet 50 greatly is its flight retarded
! by atmospheric resistance that it soon
| slacEens to less than the velocity of sound,
| The two rates are therefore so nearly alike
that either may be taken as a pretty fair
| representative Of the other.
| Should the time ever arrive-and there
| is no telling what may or may not be eX-
pected-when railway speed shall equal
| that of sound then several rather queer