The Washington times., 1906-05-09
QUERIES
WELL CONSIDERED
Expert Replies to Questions
Of Importance.
THE VELOCITY OF LIGHT
Comparison Made With Flight in Air
as to That of Interstalar
Space
THE VELOCITY OF LIGHT
By PROF. EDGAR L. LARKIN.

@ l. Is not the velocity Of light frst
measured in air. and then compared with
its velocity IN the interstellar space2
SUBSCRIBER.
1876 Page street, San Francisco
\. I. Il is. but the difference between
the two velocities is small indeed. be-
ing only 20 millionths slower in the
atmosphere For the index Of refrac-
I tion IN air. from a vacuum is I.O00294
/ The index OF refraction is the ratio
between the sines Of the angles Of Incl
dent light and the bending aside Of the
refracued ray. There are two WAYS OF
determining the velocity OF light as
Economically When found IL may be
compared with the speed in air at the
earJh's surface.
@ ? Is not the speed of light in vacuo
If space between the stars is a va
cuum-not impeded and therefore in
stshianeoGs? a SUBSCRIBER
a. , No. not instantaneous for II
takes one second Of time for light 10
move $4,000 miles And at this rate in
requires four years and four months for
Llsht Ll.=. 20 reach the earth from the near
est star. the star Alpha Centaur.
-. 3 How long does IL take for light
20 travel from the sun TO the planet
Neptunez a SUBCRIBER.
A ) -Four hours nine minutes thirty
seconds. the distance being 2,S00 0oo. .0G0
miles
c. 4 What is the speed Of the earth
on its orbit? a L
Leadviue. Col.
A. 4. 1887 miles per second. lilo
miles miles per minute. almost 5000 miles per
@ 5 Could you tell. through the COL
uEnns OF st,.I The Times. why Mars appears
OF a redolSh color2 A SUBSCRIBER
San Jose; High School. o6.
signed-an guesSes. One is. that Mars
has red soil; another. red vegetation in
stead Of green The writer DeIIeves the
red tint IS due 10 the great law OF Sc
lective absorption OF light waves from
the sun, by the atmosphere around Mars
by clouds In its upper air and by dust
IN. IN ne nlsher regions. one reason why
we have deep red sunsets here on the
earth is because the air with its load
Of vapors and dust particles selects
slLts out Quenches or absorbs all the
Here on Echo mountain we have pur-
pie. yellow. blue. and, a times violet
sunset colors- And in these all colors
OF the solar spectrum are quenched, ex-
cept those that find their way through
the aerial Instructions.
9 s, Please explain Catalysis.
\. 8, This is difficult indeed. Cat5Iy-
sis IS one OF the most remarkable forms
of activity known TO chemists Il is
the action OF matter on ether matter
producing wonderful changes. without
itself being affected. Platinum is a ca
talyJic body, Thus. drop alcohol on
DoNGeIEu PLATINUM anu IL turns 10 ace
sic acid. No change takes place in the
platinum. except that Il becomes heated
ForniC acid is changed TO carbOnic acid
IL IL touches fine particles Of the metal
platinum. II n thin foil Of platinum ia
placed in mixture of oxygen and hy-
drogen Of the proper proportions the two
gases Will unite and form water There
are other catalytiC substances. The
cause Of Catalysis is not known but II
is supposed To be electrical The coils
become hot. When II cooIs Il can cause
more gases to produce water and so on
indefinitely The mystery is where does
the metal get its energy2 Some biolO-
gists have advanced the theory that life
may have been caused on the ancient
and humid earth by catalytic action
Lowe Observatory. April. 1906.