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THE SEVEN FOLLIES
OF SCIENCE
A
POPULAR ACCOUNT OF THE MOST FAMOUS
SCIENTIFIC IMPOSSIBILITIES
AND THE ATTEMPTS WHICH HAVE BEEN MADE TO SOLVE THEM.
TO WHICH IS ADDED A SMALL BUDGET OF INTERESTING
PARADOXES, ILLUSIONS, AND MARVELS.
WITH NUMEROUS ILLUSTRATIONS
BY
JOHN PHIN
AUTHOR OF "HOW TO USE THE MICROSCOPE"; "THE WORKSHOP COMPANION";
"THE SHAKESPEARE CYCLOPEDIA"; EDITOR MARQUIS OF WORCESTER'S,
"CENTURY OF INVENTIONS"; ETC.
SECOND EDITION
[Device]
NEW YORK
D. VAN NOSTRAND COMPANY
23 MURRAY AND 27 WARREN STS.
1906
COPYRIGHT, 1906,
BY D. VAN NOSTRAND COMPANY.
PREFACE
In the following pages I have endeavored to give a simple account of
problems which have occupied the attention of the human mind ever since
the dawn of civilization, and which can never lose their interest until
time shall be no more. While to most persons these subjects will have
but an historical interest, yet even from this point of view they are of
more value than the history of empires, for they are the intellectual
battlefields upon which much of our progress in science has been won. To
a few, however, some of them may be of actual practical importance, for
although the schoolmaster has been abroad for these many years, it is an
unfortunate fact that the circle-squarer and the perpetual-motion-seeker
have not ceased out of the land.
In these days of almost miraculous progress it is difficult to realize
that there may be such a thing as a scientific impossibility. I have
therefore endeavored to point out where the line must be drawn, and by
way of illustration I have added a few curious paradoxes and marvels,
some of which show apparent contradictions to known laws of nature, but
which are all simply and easily explained when we understand the
fundamental principles which govern each case.
In presenting the various subjects which are here discussed, I have
endeavored to use the simplest language and to avoid entirely the use of
mathematical formulae, for I know by large experience that these are
the bugbear of the ordinary reader, for whom this volume is specially
intended. Therefore I have endeavored to state everything in such a
simple manner that any one with a mere common school education can
understand it. This, I trust, will explain the absence of everything
which requires the use of anything higher than the simple rules of
arithmetic and the most elementary propositions of geometry. And even
this I have found to be enough for many lawyers, physicians, and
clergymen who, in the ardent pursuit of their professions, have
forgotten much that they learned at college. And as I hope to find many
readers amongst intelligent mechanics, I have in some cases suggested
mechanical proofs which any expert handler of tools can easily carry
out.
As a matter of course, very little originality is claimed for anything
in the book,--the only points that are new being a few illustrations of
well-known principles, some of which had already appeared in "The Young
Scientist" and "Self-education for Mechanics." Whenever the exact words
of an author have been used, credit has always been given; but in regard
to general statements and ideas, I must rest content with naming the
books from which I have derived the greatest assistance. Ozanam's
"Recreations in Science and Natural Philosophy," in the editions of
Hutton (1803) and Riddle (1854), has been a storehouse of matter. Much
has been gleaned from the "Budget of Paradoxes" by Professor De Morgan
and also from Professor W. W. R. Ball's "Mathematical Recreations and
Problems." Those who wish to inform themselves in regard to what has
been done by the perpetual-motion-mongers must consult Mr. Dirck's two
volumes entitled "Perpetuum Mobile" and I have made free use of his
labors. To these and one or two others I acknowledge unlimited credit.
Some of the marvels which are here described, although very old, are not
generally known, and as they are easily put in practice they may afford
a pleasant hour's amusement to the reader and his friends.
JOHN PHIN
_Paterson, N. J., July, 1905._
CONTENTS
Preface
THE SEVEN FOLLIES OF SCIENCE
PAGE
Introductory Note 1
I Squaring the Circle 9
II The Duplication of the Cube 30
III The Trisection of an Angle 33
IV Perpetual Motion 36
V The Transmutation of Metals--Alchemy 79
VI The Fixation of Mercury 92
VII The Universal Medicine and the Elixir of Life 95
ADDITIONAL FOLLIES
Perpetual or Ever-burning Lamps 100
The Alkahest or Universal Solvent 104
Palingenesy 106
The Powder of Sympathy 111
A SMALL BUDGET OF PARADOXES, ILLUSIONS, AND MARVELS
(WITH APOLOGIES TO PROFESSOR DE MORGAN)
The Fourth Dimension 117
How a Space may be apparently Enlarged by merely changing
its Shape 126
Can a Man Lift Himself by the Straps of his Boots? 128
How a Spider Lifted a Snake 130
How the Shadow may be made to move backward on the Sun-dial 133
How a Watch may be used as a Compass 134
Micrography or Minute Writing. Writing so fine that the
whole Bible, if written in characters of the same size,
might be inscribed twenty-two times on a square inch 136
Illusions of the Senses 149
Taste and Smell 150
Sense of Heat 150
Sense of Hearing 150
Sense of Touch--One Thing Appearing as Two 151
How Objects may be apparently Seen through a Hole in the
Hand 156
How to See (apparently) through a Solid Brick 158
CURIOUS ARITHMETICAL PROBLEMS
The Chess-board Problem 163
The Nail Problem 164
A Question of Population 165
How to Become a Millionaire 166
The Actual Cost and Present Value of the First Folio Shakespeare 168
Arithmetical Puzzles 170
Archimedes and His Fulcrum 171
THE SEVEN FOLLIES OF SCIENCE
The difficult, the dangerous, and the impossible have always had a
strange fascination for the human mind. We see this every day in the
acts of boys who risk life and limb in the performance of useless but
dangerous feats, and amongst children of larger growth we find
loop-the-loopers, bridge-jumpers, and all sorts of venture-seekers to
whom much of the attraction of these performances is undoubtedly the
mere risk that is involved, although, perhaps, to some extent, notoriety
and money-making may contribute their share. Many of our readers will
doubtless remember the words of James Fitz-James, in "The Lady of the
Lake":
Or, if a path be dangerous known
The danger's self is lure alone.
And in commenting on the old-time game laws of England, Froude, the
historian, says: "Although the old forest laws were terrible, they
served only to enhance the excitement by danger."
That which is true of physical dangers holds equally true in regard to
intellectual difficulties. Professor De Morgan tells us, in his "Budget
of Paradoxes," that he once gave a lecture on "Squaring the Circle" and
that a gentleman who was introduced to it by what he said, remarked loud
enough to be heard by all around: "Only prove to me that it is
impossible and I will set about it this very evening."
Therefore it is not to be wondered at that certain very difficult, or
perhaps impossible problems have in all ages had a powerful fascination
for certain minds. In that curious _olla podrida_ of fact and fiction,
"The Curiosities of Literature," D'Israeli gives a list of six of these
problems, which he calls "The Six Follies of Science." I do not know
whether the phrase "Follies of Science" originated with him or not, but
he enumerates the Quadrature of the Circle; the Duplication, or, as he
calls it, the Multiplication of the Cube; the Perpetual Motion; the
Philosophical Stone; Magic, and Judicial Astrology, as those known to
him. This list, however, has no classical standing such as pertains to
the "Seven Wonders of the World," the "Seven Wise Men of Greece," the
"Seven Champions of Christendom," and others. There are some well-known
follies that are omitted, while some authorities would peremptorily
reject Magic and Judicial Astrology as being attempts at fraud rather
than earnest efforts to discover and utilize the secrets of nature. The
generally accepted list is as follows:
1. The Quadrature of the Circle or, as it is called in
the vernacular, "Squaring the Circle."
2. The Duplication of the Cube.
3. The Trisection of an Angle.
4. Perpetual Motion.
5. The Transmutation of the Metals.
6. The Fixation of Mercury.
7. The Elixir of Life.
The Transmutation of the Metals, the Fixation of Mercury, and the Elixir
of Life might perhaps be properly classed as one, under the head of the
Philosopher's Stone, and then Astrology and Magic might come in to make
up the mystic number Seven.
The expression "Follies of Science" does not seem a very appropriate
one. Real science has no follies. Neither can these vain attempts be
called _scientific_ follies because their very essence is that they are
unscientific. Each one is really a veritable "Will-o'-the-Wisp" for
unscientific thinkers, and there are many more of them than those that
we have here named. But the expression has been adopted in literature
and it is just as well to accept it. Those on the list that we have
given are the ones that have become famous in history and they still
engage the attention of a certain class of minds. It is only a few
months since a man who claims to be a professional architect and
technical writer put forth an alleged method of "squaring the circle,"
which he claims to be "exact"; and the results of an attempt to make
liquid air a pathway to perpetual motion are still in evidence, as a
minus quantity, in the pockets of many who believed that all things are
possible to modern science. And indeed it is this false idea of the
possibility of the impossible that leads astray the followers of these
false lights. Inventive science has accomplished so much--many of her
achievements being so astounding that they would certainly have seemed
miracles to the most intelligent men of a few generations ago--that the
ordinary mind cannot see the difference between unknown possibilities
and those things which well-established science pronounces to be
impossible, because they contradict fundamental laws which are
thoroughly established and well understood.
Thus any one who would claim that he could make a plane triangle in
which the three angles would measure more than two right angles, would
show by this very claim that he was entirely ignorant of the first
principles of geometry. The same would be true of the man who would
claim that he could give, in exact figures, the diagonal of a square of
which the side is exactly one foot or one yard, and it is also true of
the man who claims that he can give the exact area of a circle of which
either the circumference or the diameter is known with precision. That
they cannot both be known exactly is very well understood by all who
have studied the subject, but that the area, the circumference, and the
diameter of a circle may all be known with an exactitude which is far in
excess of anything of which the human mind can form the least
conception, is quite true, as we shall show when we come to consider the
subject in its proper place.
These problems are not only interesting historically but they are
valuable as illustrating the vagaries of the human mind and the
difficulties with which the early investigators had to contend. They
also show us the barriers over which we cannot pass, and they enforce
the immutable character of the natural laws which govern the world
around us. We hear much of the progress of science and of the changes
which this progress has brought about, but these changes never affect
the fundamental facts and principles upon which all true science is
based. Theories and explanations and even practical applications change
or pass away, so that we know them no more, but nature remains the same
throughout the ages. No new theory of electricity can ever take away
from the voltaic battery its power, or change it in any respect, and no
new discovery in regard to the constitution of matter can ever lessen
the eagerness with which carbon and oxygen combine together. Every
little while we hear of some discovery that is going to upset all our
preconceived notions and entirely change those laws which long
experience has proved to be invariable, but in every case these alleged
discoveries have turned out to be fallacies. For example, the wonderful
properties of radium have led some enthusiasts to adopt the idea that
many of our old notions about the conservation of energy must be
abandoned, but when all the facts are carefully examined it is found
that there is no rational basis for such views. Upon this point Sir
Oliver Lodge says:
"There is absolutely no ground for the popular and gratuitous
surmise that radium emits energy without loss or waste of any kind,
and that it is competent to go on forever. The idea, at one time
irresponsibly mooted, that it contradicted the principle of the
conservation of energy, and was troubling physicists with the idea
that they must overhaul their theories--a thing which they ought
always to be delighted to do on good evidence--this idea was a
gratuitous absurdity, and never had the slightest foundation. It is
reasonable to suppose, however, that radium and the other like
substances are drawing upon their own stores of internal atomic
energy, and thereby gradually disintegrating and falling into other
and ultimately more stable forms of matter."
One would naturally suppose that the extensive diffusion of sound
scientific knowledge which has taken place during the century just past,
would have placed these problems amongst the lumber of past ages; but it
seems that some of them, particularly the squaring of the circle and
perpetual motion, still occupy considerable space in the attention of
the world, and even the futile chase after the "Elixir of Life" has not
been entirely abandoned. Indeed certain professors who occupy prominent
official positions, assert that they have made great progress towards
its attainment. In view of such facts one is almost driven to accept the
humorous explanation which De Morgan has offered and which he bases on
an old legend relating to the famous wizard, Michael Scott. The
generally accepted tradition, as related by Sir Walter Scott in his
notes to the "Lay of the Last Minstrel," is as follows:
"Michael Scott was, once upon a time, much embarrassed by a spirit
for whom he was under the necessity of finding constant employment.
He commanded him to build a 'cauld,' or dam head across the Tweed at
Kelso; it was accomplished in one night, and still does honor to the
infernal architect. Michael next ordered that Eildon Hill, which was
then a uniform cone, should be divided into three. Another night was
sufficient to part its summit into the three picturesque peaks which
it now bears. At length the enchanter conquered this indefatigable
demon, by employing him in the hopeless task of making ropes out of
sea-sand."
Whereupon De Morgan offers the following exceedingly interesting
continuation of the legend:
"The recorded story is that Michael Scott, being bound by contract
to procure perpetual employment for a number of young demons, was
worried out of his life in inventing jobs for them, until at last he
set them to make ropes out of sea-sand, which they never could do.
We have obtained a very curious correspondence between the wizard
Michael and his demon slaves; but we do not feel at liberty to say
how it came into our hands. We much regret that we did not receive
it in time for the British Association. It appears that the story,
true as far as it goes, was never finished. The demons easily
conquered the rope difficulty, by the simple process of making the
sand into glass, and spinning the glass into thread which they
twisted. Michael, thoroughly disconcerted, hit upon the plan of
setting some to square the circle, others to find the perpetual
motion, etc. He commanded each of them to transmigrate from one
human body into another, until their tasks were done. This explains
the whole succession of cyclometers and all the heroes of the
Budget. Some of this correspondence is very recent; it is much
blotted, and we are not quite sure of its meaning. It is full of
figurative allusions to driving something illegible down a steep
into the sea. It looks like a humble petition to be allowed some
diversion in the intervals of transmigration; and the answer is:
"'Rumpat et serpens iter institutum'
"a line of Horace, which the demons interpret as a direction to come
athwart the proceedings of the Institute by a sly trick."
And really those who have followed carefully the history of the men who
have claimed that they had solved these famous problems, will be almost
inclined to accept De Morgan's ingenious explanation as something more
than a mere "skit." The whole history of the philosopher's stone, of
machines and contrivances for obtaining perpetual motion, and of
circle-squaring, is permeated with accounts of the most gross and
obvious frauds. That ignorance played an important part in the conduct
of many who have put forth schemes based upon these pretended solutions
is no doubt true, but that a deliberate attempt at absolute fraud was
the mainspring in many cases cannot be denied. Like _Dousterswivel_ in
"The Antiquary," many of the men who advocated these delusions may have
had a sneaking suspicion that there might be some truth in the doctrines
which they promulgated; but most of them knew that their particular
claims were groundless, and that they were put forward for the purpose
of deceiving some confiding patron from whom they expected either money
or the credit and glory of having done that which had been hitherto
considered impossible.
Some of the questions here discussed have been called "scientific
impossibilities"--an epithet which many have considered entirely
inapplicable to any problem, on the ground that all things are possible
to science. And in view of the wonderful things that have been
accomplished in the past, some of my readers may well ask: "Who shall
decide when doctors disagree?"
Perhaps the best answer to this question is that given by Ozanam, the
old historian of these and many other scientific puzzles. He claimed
that "it was the business of the Doctors of the Sorbonne to discuss, of
the Pope to decide, and of a mathematician to go straight to heaven in a
perpendicular line!"
In this connection the words of De Morgan have a deep significance.
Alluding to the difficulty of preventing men of no authority from
setting up false pretensions and the impossibility of destroying the
assertions of fancy speculation, he says: "Many an error of thought and
learning has fallen before a gradual growth of thoughtful and learned
opposition. But such things as the quadrature of the circle, etc., are
never put down. And why? Because thought can influence thought, but
thought cannot influence self-conceit; learning can annihilate learning;
but learning cannot annihilate ignorance. A sword may cut through an
iron bar, and the severed ends will not reunite; let it go through the
air, and the yielding substance is whole again in a moment."
I.
SQUARING THE CIRCLE
Undoubtedly one of the reasons why this problem has received so much
attention from those whose minds certainly have no special leaning
towards mathematics, lies in the fact that there is a general impression
abroad that the governments of Great Britain and France have offered
large rewards for its solution. De Morgan tells of a Jesuit who came all
the way from South America, bringing with him a quadrature of the circle
and a newspaper cutting announcing that a reward was ready for the
discovery in England. As a matter of fact his method of solving the
problem was worthless, and even if it had been valuable, there would
have been no reward.
Another case was that of an agricultural laborer who spent his
hard-earned savings on a journey to London, carrying with him an alleged
solution of the problem, and who demanded from the Lord Chancellor the
sum of one hundred thousand pounds, which he claimed to be the amount of
the reward offered and which he desired should be handed over forthwith.
When he failed to get the money he and his friends were highly indignant
and insisted that the influence of the clergy had deprived the poor man
of his just deserts!
And it is related that in the year 1788, one of these deluded
individuals, a M. de Vausenville, actually brought an action against
the French Academy of Sciences to recover a reward to which he felt
himself entitled. It ought to be needless to say that there never was a
reward offered for the solution of this or any other of the problems
which are discussed in this volume. Upon this point De Morgan has the
following remarks:
"Montucla says, speaking of France, that he finds three notions
prevalent among the cyclometers [or circle-squarers]: 1. That there
is a large reward offered for success; 2. That the longitude problem
depends on that success; 3. That the solution is the great end and
object of geometry. The same three notions are equally prevalent
among the same class in England. No reward has ever been offered by
the government of either country. The longitude problem in no way
depends upon perfect solution; existing approximations are
sufficient to a point of accuracy far beyond what can be wanted. And
geometry, content with what exists, has long pressed on to other
matters. Sometimes a cyclometer persuades a skipper, who has made
land in the wrong place, that the astronomers are in fault for using
a wrong measure of the circle; and the skipper thinks it a very
comfortable solution! And this is the utmost that the problem ever
has to do with longitude."
In the year 1775 the Royal Academy of Sciences of Paris passed a
resolution not to entertain communications which claimed to give
solutions of any of the following problems: The duplication of the cube,
the trisection of an angle, the quadrature of a circle, or any machine
announced as showing perpetual motion. And we have heard that the Royal
Society of London passed similar resolutions, but of course in the case
of neither society did these resolutions exclude legitimate mathematical
investigations--the famous computations of Mr. Shanks, to which we shall
have occasion to refer hereafter, were submitted to the Royal Society of
London and published in their Transactions. Attempts to "square the
circle," when made intelligently, were not only commendable but have
been productive of the most valuable results. At the same time there is
no problem, with the possible exception of that of perpetual motion,
that has caused more waste of time and effort on the part of those who
have attempted its solution, and who have in almost all cases been
ignorant both of the nature of the problem and of the results which have
been already attained. From Archimedes down to the present time some of
the ablest mathematicians have occupied themselves with the quadrature,
or, as it is called in common language, "the squaring of the circle";
but these men are not to be placed in the same class with those to whom
the term "circle-squarers" is generally applied.
As already noted, the great difficulty with most circle-squarers is that
they are ignorant both of the nature of the problem to be solved and of
the results which have been already attained. Sometimes we see it
explained as the drawing of a square inside a circle and at other times
as the drawing of a square around a circle, but both these problems are
amongst the very simplest in practical geometry, the solutions being
given in the sixth and seventh propositions of the Fourth Book of
Euclid. Other definitions have been given, some of them quite absurd.
Thus in France, in 1753, M. de Causans, of the Guards, cut a circular
piece of turf, squared it, and from the result deduced original sin and
the Trinity. He found out that the circle was equal to the square in
which it is inscribed, and he offered a reward for the detection of any
error, and actually deposited 10,000 francs as earnest of 300,000. But
the courts would not allow any one to recover.
In the last number of the Athenaeum for 1855 a correspondent says "the
thing is no longer a _problem_ but an _axiom_." He makes the square
equal to a circle by making each side equal to a quarter of the
circumference. As De Morgan says, he does not know that the area of the
circle is greater than that of any other figure of the same circuit.
Such ideas are evidently akin to the poetic notion of the quadrature.
Aristophanes, in the "Birds," introduces a geometer, who announces his
intention to make a _square circle_. And Pope in the "Dunciad" delivers
himself as follows:
Mad Mathesis alone was unconfined,
Too mad for mere material chains to bind,--
Now to pure space lifts her ecstatic stare,
Now, running round the circle, finds it square.
The author's note explains that this "regards the wild and fruitless
attempts of squaring the circle." The poetic idea seems to be that the
geometers try to make a square circle.
As stated by all recognized authorities, the problem is this: To
describe a square which shall be exactly equal in area to a given
circle.
The solution of this problem may be given in two ways: (1) the
arithmetical method, by which the area of a circle is found and
expressed numerically in square measure, and (2) the geometrical
quadrature, by which a square, equal in area to a given circle, is
described by means of rule and compasses alone.
Of course, if we know the area of the circle, it is easy to find the
side of a square of equal area; this can be done by simply extracting
the square root of the area, provided the number is one of which it is
possible to extract the square root. Thus, if we have a circle which
contains 100 square feet, a square with sides of 10 feet would be
exactly equal to it. But the ascertaining of the area of the circle is
the very point where the difficulty comes in; the dimensions of circles
are usually stated in the lengths of the diameters, and when this is the
case, the problem resolves itself into another, which is: To find the
area of a circle when the diameter is given.
Now Archimedes proved that the area of any circle is equal to that of a
triangle whose base has the same length as the circumference and whose
altitude or height is equal to the radius. Therefore if we can find the
length of the circumference when the diameter is given, we are in
possession of all the points needed to enable us to "square the circle."
In this form the problem is known to mathematicians as that of the
rectification of the curve.
In a practical form this problem must have presented itself to
intelligent workmen at a very early stage in the progress of operative
mechanics. Architects, builders, blacksmiths, and the makers of chariot
wheels and vessels of various kinds must have had occasion to compare
the diameters and circumferences of round articles. Thus in I Kings,
vii, 23, it is said of Hiram of Tyre that "he made a molten sea, ten
cubits from the one brim to the other; it was round all about * * * and
a line of thirty cubits did compass it round about," from which it has
been inferred that among the Jews, at that time, the accepted ratio was
3 to 1, and perhaps, with the crude measuring instruments of that age,
this was as near as could be expected. And this ratio seems to have been
accepted by the Babylonians, the Chinese, and probably also by the
Greeks, in the earliest times. At the same time we must not forget that
these statements in regard to the ratio come to us through historians
and prophets, and may not have been the figures used by trained
mechanics. An error of one foot in a hoop made to go round a tub or
cistern of seven feet in diameter, would hardly be tolerated even in an
apprentice.
The Egyptians seem to have reached a closer approximation, for from a
calculation in the Rhind papyrus, the ratio of 3.16 to 1 seems to have
been at one time in use. It is probable, however, that in these early
times the ratio accepted by mechanics in general was determined by
actual measurement, and this, as we shall see hereafter, is quite
capable of giving results accurate to the second fractional place, even
with very common apparatus.
To Archimedes, however, is generally accorded the credit of the first
attempt to solve the problem in a scientific manner; he took the
circumference of the circle as intermediate between the perimeters of
the inscribed and the circumscribed polygons, and reached the conclusion
that the ratio lay between 3-1/7 and 3-10/71, or between 3.1428 and
3.1408.
This ratio, in its more accurate form of 3.141592.. is now known by the
Greek letter [pi] (pronounced like the common word _pie_), a symbol
which was introduced by Euler, between 1737 and 1748, and which is now
adopted all over the world. I have, however, used the term ratio, or
value of the ratio instead, throughout this chapter, as probably being
more familiar to my readers.
Professor Muir justly says of this achievement of Archimedes, that it is
"a most notable piece of work; the immature condition of arithmetic, at
the time, was the only real obstacle preventing the evaluation of the
ratio to any degree of accuracy whatever."
And when we remember that neither the numerals now in use nor the Arabic
numerals, as they are usually called, nor any system equivalent to our
decimal system, was known to these early mathematicians, such a
calculation as that made by Archimedes was a wonderful feat.
If any of my readers, who are familiar with the Hebrew or Greek numbers,
and the mode of representing them by letters, will try to do any of
those more elaborate sums which, when worked out by modern methods, are
mere child's play in the hands of any of the bright scholars in our
common schools, they will fully appreciate the difficulties under which
Archimedes labored.
Or, if ignorant of Greek and Hebrew, let them try it with the Roman
numerals, and multiply XCVIII by MDLVII, without using Arabic or common
numerals. Professor McArthur, in his article on "Arithmetic" in the
Encyclopaedia Britannica, makes the following statement on this point:
"The methods that preceded the adoption of the Arabic numerals were
all comparatively unwieldy, and very simple processes involved great
labor. The notation of the Romans, in particular, could adapt itself
so ill to arithmetical operations, that nearly all their
calculations had to be made by the abacus. One of the best and most
manageable of the ancient systems is the Greek, though that, too, is
very clumsy."
After Archimedes, the most notable result was that given by Ptolemy, in
the "Great Syntaxis." He made the ratio 3.141552, which was a very close
approximation.
For several centuries there was little progress towards a more accurate
determination of the ratio. Among the Hindoos, as early as the sixth
century, the now well-known value, 3.1416, had been obtained by
Arya-Bhata, and a little later another of their mathematicians came to
the conclusion that the square root of 10 was the true value of the
ratio. He was led to this by calculating the perimeters of the
successive inscribed polygons of 12, 24, 48, and 96 sides, and finding
that the greater the number of sides the nearer the perimeter of the
polygon approached the square root of 10. He therefore thought that the
perimeter or circumference of the circle itself would be the square root
of exactly 10. It is too great, however, being 3.1622 instead of
3.14159... The same idea is attributed to Bovillus, by Montucla.
By calculating the perimeters of the inscribed and circumscribed
polygons, Vieta (1579) carried his approximation to ten fractional
places, and in 1585 Peter Metius, the father of Adrian, by a lucky step
reached the now famous fraction 355/113, or 3.14159292, which is correct
to the sixth fractional place. The error does not exceed one part in
thirteen millions.
At the beginning of the seventeenth century, Ludolph Van Ceulen reached
35 places. This result, which "in his life he found by much labor," was
engraved upon his tombstone in St. Peter's Church, Leyden. The monument
has now unfortunately disappeared.
From this time on, various mathematicians succeeded, by improved
methods, in increasing the approximation. Thus in 1705, Abraham Sharp
carried it to 72 places; Machin (1706) to 100 places; Rutherford (1841)
to 208 places, and Mr. Shanks in 1853, to 607 places. The same computer
in 1873 reached the enormous number of 707 places.
Printed in type of the same size as that used on this page, these
figures would form a line nearly six feet long.
As a matter of interest I give here the value of the ratio of the
circumference to the diameter, to 127 places:
3.14159 26535 89793 23846 26433 83279 50288 41971
69399 37510 58209 74944 59230 78164 06286 20899
86280 34825 34211 70679 82148 08651 32723 06647
09384 46+
The degree of accuracy which may be attained by using a ratio carried to
only ten fractional places, far exceeds anything that can be required in
even the finest work, and indeed it is beyond anything attainable by
means of our present tools and instruments. For example: If the length
of a curve of 100 feet radius were determined by a value of ten
fractional places, the result would not err by the one-millionth part of
an inch, a quantity which is quite invisible under the best microscopes
of the present day. This shows us that in any calculations relating to
the dimensions of the earth, such as longitude, etc., we have at our
command, in the 127 places of figures given above, an exactness which
for all practical purposes may be regarded as absolute. This will be
best appreciated by a consideration of the fact that if the earth were a
perfect sphere and if we knew its exact diameter, we could calculate so
exactly the length of an iron hoop which would go round it, that the
difference produced by a change of temperature equal to the millionth of
a millionth part of a degree Fahrenheit, would far exceed the error
arising from the difference between the true ratio and the result thus
reached.
Such minute quantities are far beyond the powers of conception of even
the most thoroughly trained human mind, but when we come to use six and
seven hundred places the results are simply astounding. Professor De
Morgan, in his "Budget of Paradoxes," gives the following illustration
of the extreme accuracy which might be attained by the use of 607
fractional places, the highest number which had been reached when he
wrote:
"Say that the blood-globule of one of our animalcules is a millionth
of an inch in diameter.[1] Fashion in thought a globe like our own,
but so much larger that our globe is but a blood-globule in one of
its animalcules; never mind the microscope which shows the creature
being rather a bulky instrument. Call this the first globule above
us. Let the first globe above us be but a blood-globule, as to size,
in the animalcule of a still larger globe, which call the second
globe above us. Go on in this way to the twentieth globe above us.
Now, go down just as far on the other side. Let the blood-globule
with which we started be a globe peopled with animals like ours, but
rather smaller, and call this the first globe below us. This is a
fine stretch of progression both ways. Now, give the giant of the
twentieth globe above us the 607 decimal places, and, when he has
measured the diameter of his globe with accuracy worthy of his size,
let him calculate the circumference of his equator from the 607
places. Bring the little philosopher from the twentieth globe below
us with his very best microscope, and set him to see the small error
which the giant must make. He will not succeed, unless his
microscopes be much better for his size than ours are for ours."
It would of course be impossible for any human mind to grasp the range
of such an illustration as that just given. At the same time these
illustrations do serve in some measure to give us an impression, if not
an idea, of the vastness on the one hand and the minuteness on the other
of the measurements with which we are dealing. I therefore offer no
apology for giving another example of the nearness to absolute accuracy
with which the circle has been "squared."
It is common knowledge that light travels with a velocity of about
185,000 miles per second. In other words, light would go completely
round the earth in a little more than one-eighth of a second, or, as
Herschel puts it, in less time than it would take a swift runner to make
a single stride. Taking this distance of 185,000 miles per second as our
unit of measurement, let us apply it as follows:
It is generally believed that our solar system is but an individual unit
in a stellar system which may include hundreds of thousands of suns like
our own, with all their attendant planets and moons. This stellar system
again may be to some higher system what our solar system is to our own
stellar system, and there may be several such gradations of systems, all
going to form one complete whole which, for want of a better name, I
shall call a universe. Now this universe, complete in itself, may be
finite and separated from all other systems of a similar kind by an
empty space, across which even gravitation cannot exert its influence.
Let us suppose that the imaginary boundary of this great universe is a
perfect circle, the extent of which is such that light, traveling at
the rate we have named (185,000 miles per second), would take millions
of millions of years to pass across it, and let us further suppose that
we know the diameter of this mighty space with perfect accuracy; then,
using Mr. Shanks' 707 places of decimal fractions, we could calculate
the circumference to such a degree of accuracy that the error would not
be visible under any microscope now made.
An illustration which may impress some minds even more forcibly than
either of those which we have just given, is as follows:
Let us suppose that in some titanic iron-works a steel armor-plate had
been forged, perfectly circular in shape and having a diameter of
exactly 185,000,000 miles, or very nearly that of the orbit of the
earth, and a thickness of 8000 miles, or about that of the diameter of
the earth. Let us further assume that, owing to the attraction of some
immense stellar body, this huge mass has what we would call a weight
corresponding to that which a plate of the same material would have at
the surface of the earth, and let it be required to calculate the length
of the side of a square plate of the same material and thickness and
which shall be exactly equal to the circular plate.
Using the 707 places of figures of Mr. Shanks, the length of the
required side could be calculated so accurately that the difference in
weight between the two plates (the circle and the square) would not be
sufficient to turn the scale of the most delicate chemical balance ever
constructed.
Of course in assuming the necessary conditions, we are obliged to leave
out of consideration all those more refined details which would
embarrass us in similar calculations on the small scale and confine
ourselves to the purely mathematical aspect of the case; but the
stretch of imagination required is not greater than that demanded by
many illustrations of the kind.
So much, then, for what is claimed by the mathematicians; and the
certainty that their results are correct, as far as they go, is shown by
the predictions made by astronomers in regard to the moon's place in the
heavens at any given time. The error is less than a second of time in
twenty-seven days, and upon this the sailor depends for a knowledge of
his position upon the trackless deep. This is a practical test upon
which merchants are willing to stake, and do stake, billions of dollars
every day.
It is now well established that, like the diagonal and side of a square,
the diameter and circumference of any circle are incommensurable
quantities. But, as De Morgan says, "most of the quadrators are not
aware that it has been fully demonstrated that no two numbers whatsoever
can represent the ratio of the diameter to the circumference, with
perfect accuracy. When, therefore, we are told that either 8 to 25 or 64
to 201 is the true ratio, we know that it is no such thing, without the
necessity of examination. The point that is left open, as not fully
demonstrated to be impossible, is the _geometrical_ quadrature, the
determination of the circumference by the straight line and circle, used
as in Euclid."
But since De Morgan wrote, it has been shown that a Euclidean
construction is actually impossible. Those who desire to examine the
question more fully, will find a very clear discussion of the subject in
Klein's "Famous Problems in Elementary Geometry." (Boston, Ginn & Co.)
There are various geometrical constructions which give approximate
results that are sufficiently accurate for most practical purposes. One
of the oldest of these makes the ratio 3-1/7 to 1. Using this ratio we
can ascertain the circumference of a circle of which the diameter is
given by the following method: Divide the diameter into 7 equal parts by
the usual method. Then, having drawn a straight line, set off on it
three times the diameter and one of the sevenths; the result will give
the circumference with an error of less than the one twenty-five-hundredth
part or one twenty-fifth of one per cent.
If the circumference had been given, the diameter might have been found
by dividing the circumference into twenty-two parts and setting off
seven of them. This would give the diameter. A more accurate method is
as follows:
Given a circle, of which it is desired to find the length of the
circumference: Inscribe in the given circle a square, and to three times
the diameter of the circle add a fifth of the side of the square; the
result will differ from the circumference of the circle by less than
one-seventeen-thousandth part of it. Another method which gives a result
accurate to the one-seventeen-thousandth part is as follows:
[Illustration: Fig. 1.]
Let AD, Fig. 1, be the diameter of the circle, C the center, and CB
the radius perpendicular to AD. Continue AD and make DE equal to the
radius; then draw BE, and in AE, continued, make EF equal to it; if
to this line EF, its fifth part FG be added, the whole line AG will
be equal to the circumference described with the radius CA, within
one-seventeen-thousandth part.
The following construction gives even still closer results: Given the
semi-circle ABC, Fig. 2; from the extremities A and C of its diameter
raise two perpendiculars, one of them CE, equal to the tangent of 30 deg.,
and the other AF, equal to three times the radius. If the line FE be
then drawn, it will be equal to the semi-circumference of the circle,
within one-hundred-thousandth part nearly. This is an error of
one-thousandth of one per cent, an accuracy far greater than any
mechanic can attain with the tools now in use.
[Illustration: Fig. 2.]
When we have the length of the circumference and the length of the
diameter, we can describe a square which shall be equal to the area of
the circle. The following is the method:
Draw a line ACB, Fig. 3, equal to half the circumference and half the
diameter together. Bisect this line in O, and with O as a center and AO
as radius, describe the semi-circle ADB. Erect a perpendicular CD, at C,
cutting the arc in D; CD is the side of the required square which can
then be constructed in the usual manner. The explanation of this is that
CD is a mean proportional between AC and CB.
[Illustration: Fig. 3.]
De Morgan says: "The following method of finding the circumference of a
circle (taken from a paper by Mr. S. Drach in the 'Philosophical
Magazine,' January, 1863, Suppl.), is as accurate as the use of eight
fractional places: From three diameters deduct eight-thousandths and
seven-millionths of a diameter; to the result, add five per cent. We
have then not quite enough; but the shortcoming is at the rate of about
an inch and a sixtieth of an inch in 14,000 miles."
For obtaining the side of a square which shall be equal in area to a
given circle, the empirical method, given by Ahmes in the Rhind papyrus
4000 years ago, is very simple and sufficiently accurate for many
practical purposes. The rule is: Cut off one-ninth of the diameter and
construct a square upon the remainder.
This makes the ratio 3.16.. and the error does not exceed one-third of
one per cent.
There are various mechanical methods of measuring and comparing the
diameter and the circumference of a circle, and some of them give
tolerably accurate results. The most obvious device and that which was
probably the oldest, is the use of a cord or ribbon for the curved
surface and the usual measuring rule for the diameter. With an
accurately divided rule and a thin metallic ribbon which does not
stretch, it is possible to determine the ratio to the second fractional
place, and with a little care and skill the third place may be
determined quite closely.
An improvement which was no doubt introduced at a very early day is the
measuring wheel or circumferentor. This is used extensively at the
present day by country wheelwrights for measuring tires. It consists of
a wheel fixed in a frame so that it may be rolled along or over any
surface of which the measurement is desired.
This may of course be used for measuring the circumference of any circle
and comparing it with the diameter. De Morgan gives the following
instance of its use: A squarer, having read that the circular ratio was
undetermined, advertised in a country paper as follows: "I thought it
very strange that so many great scholars in all ages should have failed
in finding the true ratio and have been determined to try myself." He
kept his method secret, expecting "to secure the benefit of the
discovery," but it leaked out that he did it by rolling a twelve-inch
disk along a straight rail, and his ratio was 64 to 201 or 3.140625
exactly. As De Morgan says, this is a very creditable piece of work; it
is not wrong by 1 in 3000.
Skilful machinists are able to measure to the one-five-thousandth of an
inch; this, on a two-inch cylinder, would give the ratio correct to five
places, provided we could measure the curved line as accurately as we
can the straight diameter, but it is difficult to do this by the usual
methods. Perhaps the most accurate plan would be to use a fine wire and
wrap it round the cylinder a number of times, after which its length
could be measured. The result would of course require correction for the
angle which the wire would necessarily make if the ends did not meet
squarely and also for the diameter of the wire. Very accurate results
have been obtained by this method in measuring the diameters of small
rods.
A somewhat original way of finding the area of a circle was adopted by
one squarer. He took a carefully turned metal cylinder and having
measured its length with great accuracy he adopted the Archimedean
method of finding its cubical contents, that is to say, he immersed it
in water and found out how much it displaced. He then had all the data
required to enable him to calculate the area of the circle upon which
the cylinder stood.
Since the straight diameter is easily measured with great accuracy, when
he had the area he could readily have found the circumference by working
backward the rule announced by Archimedes, viz.: that the area of a
circle is equal to that of a triangle whose base has the same length as
the circumference and whose altitude is equal to the radius.
One would almost fancy that amongst circle-squarers there prevails an
idea that some kind of ban or magical prohibition has been laid upon
this problem; that like the hidden treasures of the pirates of old it
is protected from the attacks of ordinary mortals by some spirit or
demoniac influence, which paralyses the mind of the would-be solver and
frustrates his efforts.