The Washington herald., 1910-09-26
COLOR OF SEA AND SKY.
Lord RayIeigh Explains How 10 Get
Correct Tint of Water,

Correct Tint of Water,
IN a recent lecture az the Royal IN
stitution. Lord RayleIgh spoke on .oThe
CoIors Of Sea and SKY" says the Lon
don Times. He pointed out that for the
color Of a liquid 10 De seen properly the
light must go through II: hence a deep
colcred LIQUID did not readily show its
color. The application Of this fact 10
the color OF the sea was direct The
color OF the sea was often supposed 10
be a beautiful blue; that 10 doubt was
what was seen il certain circumstances.
but it was due not 90 the intrinsic color
OF water but 10 the reelection OF the
sky The deep-blue color OF the sea
often came out wei when the water
was rippled. because then. Of the light
seen repeatedly by the observer, more
came from the zenith than would be
the case II the water would be perfect
~ smooth. With bigger waves again,
1t was easy 10 recognize that the front
slope OF the wave showed the best blue.
The true color OF the sea might be
seen in rough water. when looking
q
the observer would perceive no blue,
but a fully developed green. II shall
low water the reflection Of the light
from the bottom revealed the true color
OF the water, except so Tar as Il was
affected by the color Of the bottom IL
self. Davy was probably the first 10
state that the color OF water was blue,
conclusion also arrived at by Bunsen.
The Belgian physicist Spring made
elaborate experiments with water con
tanned IN tubes as long as twenty-six
meters, and he described the color as a
beautiful blue. comparable only with
the pUrest blue OF the sky. But the
water must be pure. or It looked green
or even yellow. Another inquirer into
the question was Aufsess. and one OF
his observation was that for the blue
and violet end Of the spectrum water
was almost perfectly transparent, which
would sufficiently explain its blue color.
Lord Rayleigh himself had carried out
some experiments with tubes twelve feet
long, and he pointed out the Importance
Of the light used for Illuminating them,
since a little blue in that light made a
great difference in the blueness Of the
color perceived IN them. Experimenting
with water from Capri and from Suez.
he got a color which might complimentary
lily be called blue, but rather was green
ish blue. while that from the Seven
Stones Lightship. off the Cornish coast,
gave a fUll green. With carefully dis
tiled water he got only the same degree
Of bIueness as with the water from
Capri and Suez.
Turning 10 the blueness Of the sky, he
upheld the view that it was due to the
dispersal OF light by small particles.
Springs view that it was due 10 the ef-
feet OF chemical matter in the air act
ing by absorption he thought was dis
proved by the fact that the setting sun
was red. not blue, though 1t might be
that constituents OF the atmosphere, such
as oxygen, acted as a secondary cause.
1t was question Of interest what kind
Of particles caused the effect. The general
idea was that ii was dust. particles OF
water, &c, but he thought there was
no reason to doubt that for the most
part blue Of the sky was due 10 the dis
persal OF light by the actual molecules
OF the air.