W. L. (William Larkin) Webb.

Brief biography and popular account of the unparalleled discoveries of T.J.J. See .. online

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Online LibraryW. L. (William Larkin) WebbBrief biography and popular account of the unparalleled discoveries of T.J.J. See .. → online text (page 9 of 28)
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That so perplex the fond impasssiored heart
Of ever-cheated, ever-trusting man."

When will an American poet sing of the labors of the Newton
of Cosmogony? This would be a task of no mean order, and require
a genius like that of eagle-soaring Pindar. After See, too, shall
have passed away, happy will be the few who can boast that they

"Saw him in the softest lights of life,
All unwithheld, indulging to his friends
The vast unborrowed treasures of his mind,"

mild, calm and good, like Newton, but withal having also, like
the author of the Principia, vigor, and courage, to war against
wrong and injustice, whether it be practiced by a King in tramp-
ling on the rights of a University, or by a clique of grafters among
men of science. Historians have remarked that Newton's whole
life was a struggle against injustice; and as for See it is well known
that he never shirks his duty in the hard work of this world. After
truth has triumphed all seems serene and simple, but establishing
it is always a more difficult task, and thus the founder of a new
science has to have courage as well as humility.



'HE Naval Observatory at Mare Island, California, has no
telescope larger than a five-inch refractor, which is a mere
pigmy compared to the giant telescopes which Professor
See had used at the Lowell Observatory, Arizona, the Naval Obser-
vatory at Washington, D. C., and elsewhere. If therefore he was
to make any important scientific researches in California, it could
not well be with the telescope in use at Mare Island; but rather
must be work along mathematical lines, in which nothing but a
few books and a clear head is required.

It is to be remembered that in Astronomy all the important
discoveries are not made with telescopes, much of the highest work
being purely a matter of theoretical research or mathematical
calculation. There are telescopic discoveries of facts made by
looking through instruments, and others of theoretical or mathe-
matical character, even more important, made by the mind's eye,
in the quiet study of the mathematical astronomer.

As Professor See was without large instruments at Mare Is-
land, he naturally turned to account his great abilities as a mathe-
matician. Thus where a mere telescopic observer would have
failed, See achieved a triumph of the first order, when in fact no
one expected it. When he came to Mare Island in November,
1903, the place was quite unknown to the scientific world; now
it is known in the remotest parts of the earth for a series of dis-
coveries of the highest significance.

This brilliant achievement did not come by chance, but re-
sulted from the consummate ability of the astronomer in charge
of the Mare Island Observatory. See has always made it a prac-


tice to take up those lines of inquiry in which he could attain the
first rank for such is the nature of leadership; and so it was in
the unparalleled series of discoveries made in California.

The first of these discoveries related to the internal densities,
pressures, and physical constitution of the sun and planets. Prior
to Professor See's work in 1904-6 the interior constitution of the
planets was a veritable terra incognita, a subject on which nothing
was yet known; and there was little prospect that anyone would
attempt to explore the physical conditions down in the depths of
the planets. We cannot descend into the earth or other planets,
much less into the sun, and actually observe with instruments
what the conditions are in these dark and invisible regions, inside
of the heavenly bodies. Many therefore doubtless reasoned that
nothing could ever be known of the state of the matter thus inac-
cessible to our observations. It is scarcely necessary to remark
that See did not share this view he knew too well the power of

He had long ago learned to calculate all manner of things from
the Newtonian law of gravitation. And he realized that if the
arrangement of the law of density within a planet such as the earth
could be made out, it would be comparatively easy for the mathe-
matician to calculate the pressure clear down to the center of the
globe. Each layer of the globe presses upon the layers beneath
it, and the total pressure at the center is the proper sum of all these
combined pressures, which can be calculated by the higher mathe-
matical methods known as the Calculus, the first principles of
which were invented by Newton in 1666.

Now See set about the following problems:

1. To find the most probable laws of density within the sun
and planets.

2. To calculate the resulting laws of pressure in the interior
of these bodies, by the methods of higher mathematics.

3. To deduce the physical properties of matter thus im-
prisoned under tremendous pressure, and high temperature.

And by great labor during the years 1904-6 he gradually


solved all these problems, so as to give us in fact a new science of
the interior constitution of the heavenly bodies.

To understand this work, let us first consider the case of the
earth. Our globe appears to be solid, and is covered by a rocky
crust, but earthquake movements occur; and it is important to
know whether these are just beneath the surface, or deep down in
the bowels of the globe, as Humboldt believed to be the case three
quarters of a century ago.

See first investigated the law of density of the earth suggested
by Laplace, and satisfied himself by careful inquiry that it must
be either accurate or very nearly so. The proof of this result can-
not be given here, but it is a matter on which astronomers are
essentially agreed. This law of Laplace makes the density at the
earth's center 11.2, that of water being unity, and the average
density of the whole earth 5.5. Thus the density of the earth's
matter increases quite rapidly as we go down, and at the center
becomes equal to that of lead. At the surface the density is 2.55,
so that the central density is over four times that at the surface.

Without going into the methods of calculation employed by
See, we may say that he found the pressure at the earth's center
over three million atmospheres, each atmosphere being the weight
of a column of quicksilver thirty inches high, as in a barometer,
or fifteen pounds to the square inch. This made the pressure at
the earth's center over 45,000,000 pounds to the square inch.

To represent this in a simple way, imagine a column of quick-
silver an immensely heavy liquid considerably denser than
lead as long as from St. Louis to San Francisco. Let this
column be erected vertically, in a tube strong enough to hold it,
and every part of it pressing down just as quicksilver does at the
surface of the earth; then the tremendous pressure of this column
1,700 miles in length becomes just equal to the pressure at the
center of the earth.

Could any result be more wonderful than this? Yet it is very
accurate, and we may absolutely depend upon it. And not only
did See find the pressure at the center of the earth, but also the


law of its increase as we go downward, from the surface, where it
is nothing, to the center, where it becomes equal to the weight of
a vertical column of quicksilver as long as from St. Louis to San

The outcome of this study was the conclusion that the greater
the pressure the more difficult it is for the matter thus imprisoned
to circulate or move in any way. Consequently deep down in the
earth, where the pressure is very great no motion ever takes place;
and the only place where motion can occur is just beneath the
earth's crust, as in earthquake movements. In fact it was shown
by See that the deep interior of the earth always is absolutely
quiescent; and, even just beneath the surface, it takes all the
power involved in the throes of an earthquake to enable the molten
lava to readjust itself. In this readjustment of lava the crust
naturally is terribly shaken, and cities may be laid waste and
whole countries devastated.

Accordingly See was able to conclude with certainty that
Humboldt was wrong in holding that earthquake disturbances are
propagated from deep down in the globe. Measurements by
modern seismographs also show that these disturbances are shallow,
in no case exceeding a depth of some twenty miles, which is the
thickness of the earth's crust. Earthquake phenomena, however,
will be more fully discussed in the next chapter, and we must here
treat of the interior conditions of the other planets.

In general the larger the body the greater the pressure at the
center; so that the sun has at its center by far the greatest pres-
sure of any of the bodies of our solar system. The next greatest
pressure is in the center of Jupiter; then comes Neptune, Uranus,
and Saturn, the latter coming after the two former because its
average density is very small (0.71 that of water).

At the center of the sun the pressure becomes 11,215,540,300
atmospheres, each amounting to 15 pounds to the square inch.
This is equivalent to the weight of a column of quicksilver about
one-eighth as long as from the earth to the sun, when all parts of
it press downward, as at the surface of the earth. Truly an
amazing pressure!


To form some idea of the physical condition of the matter
in the sun, we must recall that it is at a temperature of millions
of degrees, and on the other hand held in confinement by this
tremendous pressure. Therefore the matter is kept so "tight"
as to be highly rigid, though it would prove to be gaseous if the
pressure were removed. On this point there is no doubt what-
ever. Though we cannot experiment with such immense forces,
we can calculate them with accuracy and certainty.

A very good comparison of the state of the matter in the
interior of the sun was made by Professor Newcomb some years
ago, when he said that if the pressure were suddenly relieved this
matter would instantly expand, and in fact explode with a violence
exceeding that of dynamite or any other known substance. If,
for example, gravitation should suddenly cease, the whole sun
would expand into a nebula filling the universe. Such a thing as
this of course will never happen, yet the picture of such an ex-
plosion enables us to realize what dreadful compression and im-
prisonment matter is subjected to in the sun's interior.

This imprisoned matter is really gaseous, and would expand
into a nebula if the pressure were relieved; but in confinement
it has the property of a solid, owing to the tremendous pressure
at a temperature of millions of degrees. See concluded that at
the surface of the sun the temperature lies between 6,000 and
12,000 degrees centigrade; and that deeper down it mounts up
enormously, according to laws which he has worked out, and at
the center probably lies between 10,000,000 and 100,000,000
degrees, on the same scale of temperature.

Now in dealing with the interior constitution of the earth
Lord Kelvin and Sir George Darwin found our globe to be a solid
of about the rigidity of steel. In other words our globe is about
as hard as a steel globe of the same size would be if the parts of
it be imagined to be devoid of the power of gravity. But gravi-
tation exists, and it is in fact the pressure under gravity which
makes the earth so highly rigid the imprisoned matter may be
molten or even gaseous, and yet so confined that it is not free to


circulate, but actually made to act as a rigid solid. By careful
mathematical calculation See proves that the earth has a rigidity
nearly as great as nickel steel used in the armor plate of our battle-

The nickel steel of moderate grade has a rigidity of about a
million atmospheres. The modern vanadium steel is said to be
even more rigid, but we need not extend the comparison. It suf-
fices to say that by considering the layers of which the earth is
made up, and the pressure in each layer, See finds for the earth
an average rigidity approaching that of nickel steel. This result
confirms the conclusion of Lord Kelvin and Sir George Darwin,
but See's reasoning is much simpler than theirs. In other words,
the rigidity of the earth is due to the pressure which makes the
matter behave as a solid; and by the theory of Professor See we
may calculate the rigidity of any layer in the globe. He finds
that the rigidity at the surface is equal to that of common granite,
which is about one- fourth that of steel; while at the center the
rigidity is three times that of armor plate or nickel steel.

One very remarkable thing about See's process for dealing
with the rigidity of the earth is the generality of the method,
which makes it applicable also to the other planets and the sun;
whereas the methods of Lord Kelvin and Darwin apply only to
the earth, and cannot be applied to the planets, sun or fixed stars.
Thus See's method is one of entire generality, like the law of New-
tonian gravitation, whereas the method of Kelvin and Darwin
applies only to the earth, and is thus extremely special. It may
be said therefore that See generalized the law of rigidity, some-
what as Newton did the law of gravitation. For before Newton's
work of 1685, Dr. Hooke had proved the law of gravity for the
simple case of circular motion; but Newton proved it also for the
ellipse, parabola and hyperbola, and thus generalized it for all the
orbits described by the heavenly bodies.

Applying these methods of investigation to the sun, See found
that the average rigidity of that globe is over 2,000 times that of
nickel steel used in armor plate. Surely a wonderful result! Prior

Scale showing Rigidity

of Various substances

expressed in thousands

of Atmospheres.

of Rigidity I " " 260 OOO Atmospheres
divisions - Rigidity of Nickel Steel.

Outer Tenth of the Sun's Radius, on larger Scale.

Rigidity In millions of Atmospheres, so

that 1 ^' Rigidity of Nickel Steel.

Temperature In millions of Degrees C.

Density 10 fold. Water = I.


I .5 .6 .7 .8 .9 I.

Seate o^R^rMHy tfL'-^y^JO 000 Atm?sphr e<v
gidity or Nickel Stie'l. '

The Sun:

Rigidity or Pressure in Billions of Atmospheres. I -,' Rigidity
I 000 times that of Nickel Steel used in Armor Plate.

Density on usual Scale. Water =-l.
Temperature Scale I d ^ 3 Million Decrees C.


Scale of Rigidity I c " v " 10 000 Atmospheres.
Rigidity due to Pressure is small, but
Planet may be a mas; of Solid Rock.

Scale of Rigidity I Si 10 OOO Atmospheres

Scale of Rigidity I "Si IO 000 OOO Atmospheres
Scale of Temperature I d iT'40000C.




le of Rigidity I "i 1 "- 2 OOO 000 Atmospheres.

Scale of Temperature I **-' 10 OOO C.
le of Density for all the Planets, Water = |.

F Rigidity \~=- 3 000 000 Atmo.phe
Scale of Temperature I *= 10 OOO C.


to See's work of 1904-6, many astronomers had believed that the
currents noticed at the surface of the sun extend to great depths,
and even to the very center. This was just like the geologists
believing that currents circulate deep down in the earth, which
See proved to be quite impossible. In the same way he showed
that circulation at any considerable depth in the sun could not
take place, because of the enormous pressure and great effective
rigidity of the matter. At a depth of one-tenth of the sun's radius
the rigidity is already twenty-two times that of nickel steel, and
hence See argues that all circulation in the sun is confined to a
thin layer near the surface, while the great interior globe is quies-
cent and hundreds and thousands of times more rigid than armor

These profound and original investigations give us new ideas
in science, and have revolutionized many of the old theories.
Naturally such advancement could only come from a bold and
daring leader, who had the courage to lead the way to truth, with-
out regard to traditional opinion. This power of leadership is a
striking characteristic of See. He is at home in pioneer research,
and shows the same courage and independence of mediocre opinion
that enabled Archimedes and Galileo to win victories in past
centuries. And just as they triumphed over the jealous opposi-
tion of ignorance and medievalism, so also See has blazed a sim-
ilar new and luminous path for progress throughout coming ages.

Galileo's opponents often could not refute his arguments,
as when he pointed to Jupiter's satellites as verifying his theories;
and in this perplexity they could do nothing but refuse to look
through the telescope, lest they be convinced. They did not want
to know the truth. There are still persons of that kind in the
world, and no doubt always will be.

One form of the contemptible opposition to Galileo may be
recorded here. When his opponents knew they were beaten, and
could no longer make an honest argument against the progress of
truth, they tried to get learned societies arrayed against him.
Thus it is said that the Academy of Cortona unanimously resolved


that the satellites of Jupiter did not exist. Yet Galileo would
have shown them to anyone who wished to look through the newly
invented telescope. So also there are now people of this type
who have fought the progress of See's discoveries till they found
out the futility of their efforts. Then they gave up the fight, and
now probably they would not admit that they ever opposed the
progress of his discoveries, which are in every respect comparable
to those of Galileo and Archimedes.

The modern geometer who can devise a method for inves-
tigating the physical properties of matter confined under tremen-
dous pressure and enormously high temperature, in the deep
interior of the sun and planets, where no instrument or direct
observation can ever aid us, evidently is in the same class with
the ancient mathematician who could invent burning mirrors,
and the principle of floating bodies, as well as deduce the proper-
ties of curves and spirals. And hence we have pointed out the
parallel between the labors of the celebrated geometer of Syracuse
and the famous American geometer whose discoveries have added
so much new luster to the American name.


Illustrating the relations of the mountains to the sea, which has uplifted great walls along the borders
of the Continents, by the expulsion of lava from beneath the ocean and its injection under the land.
This impressive view of the Earth shows at a glance that the mountains have been formed by the Sea.
From Frye's Complete Geography, by permission of Ginn & Co., Puolishers.


By T. J. J. SEE

AMONG all the varied natural phenomena witnessed upon
our planet nothing so excites the dread and terror of man-
kind as an earthquake, which is at once violent and so
sudden and unexpected as to alarm the calmest mind. That this
direful feeling has prevailed in all ages we are amply assured by
the comparisons made in the Bible and other venerable works of
antiquity, which make known the consternation inspired among
the people by these terrible natural commotions. Thus we read
in history that some of the Emperors of Rome, especially Trajan
and Hadrian, while witnessing the chariot races at Antioch and
other places, found it advisable to withdraw from the amphi-
theatre and retire into the open spaces, in order to avoid the danger
of falling walls. And the history of Greece and Rome abounds
in stories of the religious anxiety excited among the people by
earthquakes, which were believed to be signs of evil omen, sent
from the infernal and marine divinities, but especially Poseidon,
"the Earth-shaker/' to whom so many temples were dedicated on
isthmuses, promontories and other regions in the neighborhood
of the sea.

When a great earthquake took place, and was followed by
a series of after-shocks, impressively recalling both the terror and
the disaster of the principal disturbance, which may have laid
waste cities and devastated whole countries, it is not wonderful
that the people who had sustained such losses were troubled and
wrought up to a high pitch of excitement. In such emergencies

* Address delivered at the University of Missouri, May 30, 1907, being Lec-
ture No. 2 of a general course in Natural Philosophy. Reprinted from Popular
Astronomy No. 154, April, 1908.


the god Poseidon above all others* called forth the veneration of
the people; and he was generally held to be the most important
of the infernal and marine divinities, because he held both the
power of earthquakes and of those dreadful inundations by the
sea, which were so often noticed to accompany violent seismic
disturbances in the Peloponnesus and elsewhere.

The wide-spread alarm and religious affliction of the inhab-
itants of the Peloponnesus after the great Achaian earthquake of
373 B. C. is especially remarked by Diodorus Siculus, and other
historians. At the same time it is stated that the natural philo-
sophers explain these phenomena by natural and necessary causes,
rather than by the wrath of the gods. But during the ages of
Greek Polytheism, and even during the earlier centuries of Christi-
anity, such disasters were always believed by the multitude to be a
sign of the Divine displeasure. Sometimes they were attributed
to the wickedness of an emperor, or to the sins of factional oppo-
nents; the heathens charging them upon the Christians and the
Christians laying them to the idolatrous conduct of the heathens.

In view of the undeveloped state of Science in former times
a modern student can easily understand the great perplexity of
the ancients, in the midst of such terrible calamities. The Senate
of Rome on more than one occasion did what it could to alleviate
the sufferings of the people, which were partly real and partly
imaginary. We find several accounts of the sending of formal
embassies for the offering of public sacrifices to the angry divinities.
If these sacrifices did not quiet the agitating forces of nature, they
at least calmed the people and thus allayed their imaginary afflic-
tions and were therefore of service to the State.

It is well known that both the ablest statesmen and generals
of antiquity regarded earthquakes as proceeding from natural
causes; and I have recently been at some pains to translate the
theories held by Aristotle and other leading Greek philosophers.

" Once when an earthquake shook the ground where a Spartan army
was encamped, the whole army sang a hymn to Poseidon."

Article Poseidon, Encycl. Britannica, 9th edition.


Aristotle gives the views of those who preceded him, and his own
theory was generally adopted by his successors. We may infer
this by the way in which it was followed by such writers as Strabo
and Pliny.

Aristotle placed his discussion of earthquakes in the book on
Meteorology, because he ascribed the shaking of the earth to vapor
confined within the crust, and agitating to effect an escape, so as
to diffuse itself in the atmosphere. He recognized the high inter-
nal temperature of the earth from the warm springs observed to
break forth in many places, and from the eruptions of volcanoes
which he had witnessed in the Aeolian Islands and elsewhere.
Both he and Strabo mention eruptions occuring in the bed of the
sea, and they also notice the great seismic sea waves which fre-
quently accompany violent earthquakes originating near the sea

Aristotle and Pliny distinctly remark that earthquakes are
especially prevalent in maritime districts; and they attribute this
phenomenon to submarine passages, conceived as deep conduits,
by which air and water obtain access to the heated matter in the
bowels of the earth. They held that earthquakes are due to the
agitation of imprisoned vapors even when none of it escapes to
the surface, but all remains hidden beneath the earth's crust. That
the cause is the same when a volcanic outbreak occurs and when
only an earthquake takes place without eruption, Aristotle affirm-
ed on the ground of the similarity of the movement in the two cases.

To an unbiased naturalist like Aristotle it did not seem strange
that in the one case the vapor should break through and diffuse

Online LibraryW. L. (William Larkin) WebbBrief biography and popular account of the unparalleled discoveries of T.J.J. See .. → online text (page 9 of 28)