J.M. Barrie - "Auld Licht Idyls"

John Finley - "The French in the Heart of America"

Stephen Gwynn - "The Life of the Rt. Hon. Sir Charles W. Dilke V1"

Henrik Ibsen - "Ghosts"

Annual Bibliography of Commonwealth Literature 2007
This paper argues that discourses of love in Ghanaian market literature for youth offer a view into complex negotiations of agency and empowerment. Drawing on Deborah Durham's notion of youth as "social `shifters'" and Francis Nyamnjoh's conception of the "interconnectedness" of agency, I take Ghanaian market literature as one specific case of how African literature for youth foregrounds questions of continuity and change as African societies enter into increasingly complex global relations. In this literature for youth, received notions of love, often constructed out of impressions from American pop and hip hop music, carry new notions of agency that compete with existing "domesticated" forms. Authors like Ike Tandoh and Evelyn Tay employ discourses of love to offer youth alternative avenues for empowerment in a context of socio-economic disenfranchizement. In a creative process of "straddling", this writing both reveals and reproduces the contradictions that obtain in youth configurations of agency.

The Outline of Science, Vol. 1 (of 4)

J >> J. Arthur Thomson >> The Outline of Science, Vol. 1 (of 4)





Sec. 17

Origin of the Moon

But there is another aspect of the tides which is of vastly greater
interest and importance than the theory we have just been discussing. In
the hands of Sir George H. Darwin, the son of Charles Darwin, the tides
had been made to throw light on the evolution of our solar system. In
particular, they have illustrated the origin and development of the
system formed by our earth and moon. It is quite certain that, long ages
ago, the earth was rotating immensely faster than it is now, and that
the moon was so near as to be actually in contact with the earth. In
that remote age the moon was just on the point of separating from the
earth, of being thrown off by the earth. Earth and moon were once one
body, but the high rate of rotation caused this body to split up into
two pieces; one piece became the earth we now know, and the other became
the moon. Such is the conclusion to which we are led by an examination
of the tides. In the first place let us consider the energy produced by
the tides. We see evidences of this energy all round the word's
coastlines. Estuaries are scooped out, great rocks are gradually reduced
to rubble, innumerable tons of matter are continually being set in
movement. Whence is this energy derived? Energy, like matter, cannot be
created from nothing; what, then, is the source which makes this
colossal expenditure possible.


The Earth Slowing down

The answer is simple, but startling. _The source of tidal energy is the
rotation of the earth._ The massive bulk of the earth, turning every
twenty-four hours on its axis, is like a gigantic flywheel. In virtue of
its rotation it possesses an enormous store of energy. But even the
heaviest and swiftest flywheel, if it is doing work, or even if it is
only working against the friction of its bearings, cannot dispense
energy for ever. It must, gradually, slow down. There is no escape from
this reasoning. It is the rotation of the earth which supplies the
energy of the tides, and, as a consequence, the tides must be slowing
down the earth. The tides act as a kind of brake on the earth's
rotation. These masses of water, _held back by the moon_, exert a kind
of dragging effect on the rotating earth. Doubtless this effect,
measured by our ordinary standards, is very small; it is, however,
continuous, and in the course of the millions of years dealt with in
astronomy, this small but constant effect may produce very considerable
results.

But there is another effect which can be shown to be a necessary
mathematical consequence of tidal action. It is the moon's action on the
earth which produces the tides, but they also react on the moon. The
tides are slowing down the earth, and they are also driving the moon
farther and farther away. This result, strange as it may seem, does not
permit of doubt, for it is the result of an indubitable dynamical
principle, which cannot be made clear without a mathematical discussion.
Some interesting consequences follow.

Since the earth is slowing down, it follows that it was once rotating
faster. There was a period, a long time ago, when the day comprised only
twenty hours. Going farther back still we come to a day of ten hours,
until, inconceivable ages ago, the earth must have been rotating on its
axis in a period of from three to four hours.

At this point let us stop and inquire what was happening to the moon. We
have seen that at present the moon is getting farther and farther away.
It follows, therefore, that when the day was shorter the moon was
nearer. As we go farther back in time we find the moon nearer and nearer
to an earth rotating faster and faster. When we reach the period we have
already mentioned, the period when the earth completed a revolution in
three or four hours, we find that the moon was so near as to be almost
grazing the earth. This fact is very remarkable. Everybody knows that
there is a _critical velocity_ for a rotating flywheel, a velocity
beyond which the flywheel would fly into pieces because the centrifugal
force developed is so great as to overcome the cohesion of the molecules
of the flywheel. We have already likened our earth to a flywheel, and we
have traced its history back to the point where it was rotating with
immense velocity. We have also seen that, at that moment, the moon was
barely separated from the earth. The conclusion is irresistible. In an
age more remote the earth _did_ fly in pieces, and one of those pieces
is the moon. Such, in brief outline, is the tidal theory of the origin
of the earth-moon system.


The Day Becoming Longer

At the beginning, when the moon split off from the earth, it obviously
must have shared the earth's rotation. It flew round the earth in the
same time that the earth rotated, that is to say, the month and the day
were of equal length. As the moon began to get farther from the earth,
the month, because the moon took longer to rotate round the earth, began
to get correspondingly longer. The day also became longer, because the
earth was slowing down, taking longer to rotate on its axis, but the
month increased at a greater rate than the day. Presently the month
became equal to two days, then to three, and so on. It has been
calculated that this process went on until there were twenty-nine days
in the month. After that the number of days in the month began to
decrease until it reached its present value or magnitude, and will
continue to decrease until once more the month and the day are equal. In
that age the earth will be rotating very slowly. The braking action of
the tides will cause the earth always to keep the same face to the moon;
it will rotate on its axis in the same time that the moon turns round
the earth. If nothing but the earth and moon were involved this state of
affairs would be final. But there is also the effect of the solar tides
to be considered. The moon makes the day equal to the month, but the sun
has a tendency, by still further slowing down the earth's rotation on
its axis, to make the day equal to the year. It would do this, of
course, by making the earth take as long to turn on its axis as to go
round the sun. It cannot succeed in this, owing to the action of the
moon, but it can succeed in making the day rather longer than the month.

Surprising as it may seem, we already have an illustration of this
possibility in the satellites of Mars. The Martian day is about one
half-hour longer than ours, but when the two minute satellites of Mars
were discovered it was noticed that the inner one of the two revolved
round Mars in about seven hours forty minutes. In one Martian day,
therefore, one of the moons of Mars makes more than three complete
revolutions round that planet, so that, to an inhabitant of Mars, there
would be more than three months in a day.


BIBLIOGRAPHY

ARRHENIUS, SVANTE, _Worlds in the Making_.
CLERK-MAXWELL, JAMES, _Matter and Motion_.
DANIELL, ALFRED, _A Text-Book of the Principles of Physics_.
DARWIN, SIR G. H., _The Tides_.
HOLMAN, _Matter, Energy, Force and Work_.
KAPP, GISBERT, _Electricity_.
KELVIN, LORD, _Popular Lectures and Addresses_. Vol. i. _Constitution
of Matter._
LOCKYER, SIR NORMAN, _Inorganic Evolution_.
LODGE, SIR OLIVER, _Electrons_ and _The Ether of Space_.
PERRIN, JEAN, _Brownian Movement and Molecular Reality_.
SODDY, FREDERICK, _Matter and Energy_ and _The Interpretation of Radium_.
THOMPSON, SILVANUS P., _Light, Visible and Invisible_.
THOMSON, SIR J. J., _The Corpuscular Theory of Matter_.

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