South Bend news-times. (South Bend, Ind.) 1913-1938, 1918-12-16

Whoever thinks out the answer to
the question printed below is on the
true highway that leads to knowl-
edge. A thoushtful boy after learn
ing what his books tell him about
geography can make his knowledge
vivid, interesting and productive by
asking and answering such aues-
tions for himself School children
never dream how the best teachers
get their erudition and are able Ia
handle what they know with so
much ease and fullness.
1t is because such teachers travel
the way that William Thomson,
who afterward became the re-
nowned Lord Kelvin. pursued when,
while preparing for the great Cam
bridge university mathematical ex-
animation, spent his entire summer
vacation with a friend. afterward
Prof Blackburn spinning oval
stones on hard sea-beach, striv-
Ing to make them rise up on end
like tops.
Thomson was trying TO explain,
V hat no book then in existence did
why an ellipsoidal, or oval, body if
rapidly spun gets up and stands on
its longest axis. "COmmOn-sense'
on-lookers Gas they thought them
Iselves) smiled disdainfully at such
childish amusement for two we'll
grown young men, but young Thorn
son kept on spinning stones until ne
had solved his problem and made
himself famous.
Sometimes "supposing a case, %
/ and driving ones imagination in
harness. is very effective method
/ of clearing UP knowledge, and it Is
this plan that the writer of the fol
| lowing letter has been trying:
II have read your article about
how YOU can feel the earth turn
and an argument was brought "
which we would like 10 have YOU
settle. The argument is as follows
! a man takes a certain circumfer-
/ ence from the north pole. which
l he can cover I'm twenty four hours
1 coming TO the same starting oinr
/ if the earth were standing still
I Now. as the earth travels from ives
! to east and the man travels from
4 east to west. how soon will he reacl
the starting point? My frienf
claims twenty four hours sa,
twelve hours.-E T."
The statement is not quite n.
( luminous rs It should be Wh1
I"E. r." evidently has in his minds
/ eve is about this: \ man walks i'm
circle around The north pole. n
\ such a distance from the pole tina
/ he can cover the circumference OF
/ the circle in just twenty-four hours
( Tt is assumed that he keeps on go
/ ing without any stop. and at a uni
form speed. curing the entire in
/ tervaL The direction i'm which IN,
walks is opposite 10 that Of tn
earth's daily rotation On its axis
/ Vow If we suppose that the mar
walks steadily three miles an hou
ne will GO sevcnty-two miles I'm tn,
Twenty hours This enables U
to calculate easily how far his circl
/ lies from the pole The distance j
( seventy miles divided by twic'
the ratio Of the circumference Of
circle 20 its diameter. T. g.. by th'
approximate numbe~ 6.2S. which
/ gives for the quotieut 11.4G5. or say
in round numbers. II II miles r.
keeping at that 3istance from tn
pole, and goin- ahead at the rate %
o miles en- hour. he viii complet
the circle in tweuty-four hours. Il
order to go IN westward direc
tion he must have the pole on IN
right hand. if il were the south poi
then il would have 20 be on his left
Here a very instructive consider
alton presents itself The earth
turning in the direction opposite q
THAT in which the man Is walkln,
land II is turning az the same rat
lat which he Is walking A stou
wing on the ground within abou
i11i-2 miles OF the pole would %
lcarried eastward in "A circle abou
tie pole az the rate OF three mile