CYCLOMETRY.

I am not to enter anything I do not possess. The reader therefore will not

learn from me the feats of many a man-at-arms in these subjects. He must be

content, unless he will bestir himself for himself, not to know how Mr.

Patrick Cody trisects the angle at Mullinavat, or Professor Recalcati

squares the circle at Milan. But this last is to be done by subscription,

at five francs a head: a banker is named who guarantees restitution if the

solution be not perfectly rigorous; the banker himself, I suppose, is the

judge. I have heard of a man of business who settled the circle in this

way: if it can be reduced to a debtor and creditor account, it can

certainly be done; if not, it is not worth doing. Montucla will give the

accounts of the lawsuits which wagers on the problem have produced in

France.

Neither will I enter at length upon the success of the new squarer who

advertises (Nov. 1863) in a country paper that, having read that the

circular ratio was undetermined, "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.... I am about to secure the {209}

benefit of the discovery, so until then the public cannot know my new and

true ratio." I have been informed that this trial makes the diameter to the

circumference as 64 to 201, giving [pi] = 3.140625 exactly. The result was

obtained by the discoverer in three weeks after he first heard of the

existence of the difficulty. This quadrator has since published a little

slip, and entered it at Stationers' Hall. He says he has done it by actual

measurement; and I hear from a private source that he uses a disk of 12

inches diameter, which he rolls upon a straight rail. Mr. James Smith did

the same at one time; as did also his partisan at Bordeaux. We have, then,

both 3.125 and 3.140625, by actual measurement. The second result is more

than the first by about one part in 200. The second rolling is a very

creditable one; it is about as much below the mark as Archimedes was above

it. Its performer is a joiner, who evidently knows well what he is about

when he measures; he is not wrong by 1 in 3,000.

The reader will smile at the quiet self-sufficiency with which "I have been

determined to try myself" follows the information that "so many great

scholars in all ages" have failed. It is an admirable spirit, when

accompanied by common sense and uncommon self-knowledge. When I was an

undergraduate there was a little attendant in the library who gave me the

following,--"As to cleaning this library, Sir, if I have spoken to the

Master once about it, I have spoken fifty times: but it is of no use; he

will not employ _littery_ men; and so I am obliged to look after it

myself."

I do not think I have mentioned the bright form of quadrature in which a

square is made equal to a circle by making each side equal to a quarter of

the circumference. The last squarer of this kind whom I have seen figures

in the last number of the _Athenaeum_ for 1855: he says the thing is no

longer a _problem_, but an _axiom_. He does not know that the area of the

circle is greater than that of any other figure of the same circuit. This

any one might see without {210} mathematics. How is it possible that the

figure of greatest area should have any one length in its circuit unlike in

form to any other part of the same length?

The feeling which tempts persons to this problem is that which, in romance,

made it impossible for a knight to pass a castle which belonged to a giant

or an enchanter. I once gave a lecture on the subject: a gentleman who was

introduced to it by what I 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."

This rinderpest of geometry cannot be cured, when once it has seated itself

in the system: all that can be done is to apply what the learned call

prophylactics to those who are yet sound. When once the virus gets into the

brain, the victim goes round the flame like a moth; first one way and then

the other, beginning where he ended, and ending where he begun: thus

verifying the old line

"In girum imus nocte, ecce! et consumimur igni."[353]

Every mathematician knows that scores of methods, differing altogether from

each other in process, all end in this mysterious 3.14159..., which insists

on calling itself the circumference to a unit of diameter. A reader who is

competent to follow processes of arithmetic may be easily satisfied that

such methods do actually exist. I will give a sketch, carried out to a few

figures, of three: the first two I never met with in my reading; the third

is the old method of Vieta.[354] [I find that both the first and second

methods are contained in a theorem of Euler.]

What Mr. James Smith says of these methods is worth noting. He says I have

given three "_fancy_ proofs" of the value of [pi]: he evidently takes me to

be offering demonstration. He proceeds thus:--

"His first proof is traceable to the diameter of a circle {211} of radius

1. His second, to the side of any inscribed equilateral triangle to a

circle of radius 1. His third, to a radius of a circle of diameter 1. Now,

it may be frankly admitted that we can arrive at the same result by many

other modes of arithmetical calculation, all of which may be shown to have

some sort of relation to a circle; but, after all, these results are mere

exhibitions of the properties of numbers, and have no more to do with the

ratio of diameter to circumference in a circle than the price of sugar with

the mean height of spring tides. (_Corr._ Oct. 21, 1865)."

I quote this because it is one of the few cases--other than absolute

assumption of the conclusion--in which Mr. Smith's conclusions would be

true if his premise were true. Had I given what follows as _proof_, it

would have been properly remarked, that I had only exhibited properties of

numbers. But I took care to tell my reader that I was only going to show

him _methods_ which end in 3.14159.... The proofs that these methods

establish the value of [pi] are for those who will read and can understand.

200000000 31415 3799

66666667 2817

26666667 1363

11428571 661

5079365 321

2308802 156

1065601 76

497281 37

234014 18

110849 9

52785 5

25245 2

12118 1

5834

-------- -------- -------

314153799 31415 9265

{212}

1. Take any diameter, double it, take 1-3d of that double, 2-5ths of the

last, 3-7ths of the last, 4-9ths of the last, 5-11ths of the last, and so

on. The sum of all is the circumference of that diameter. The preceding is

the process when the diameter is a hundred millions: the errors arising

from rejection of fractions being lessened by proceeding on a thousand

millions, and striking off one figure. Here 200 etc. is double of the

diameter; 666 etc. is 1-3rd of 200 etc.; 266 etc. is 2-5ths of 666 etc.;

114 etc. is 3-7ths of 266 etc.; 507 etc. is 4-9ths of 114 etc.; and so on.

2. To the square root of 3 add its half. Take _half_ the third part of

this; half 2-5ths of the last; half 3-7ths of the last; and so on. The sum

is the circumference to a unit of diameter.

Square root of 3.... 1.73205081

.86602540

------------

2.59807621

.43301270

.08660254

1855768

412393

93726

21629

5047

1188

281

67

16

4

1

------------

3.14159265

3. Take the square root of 1/2; the square root of half of one more than

this; the square root of half of one more {213} than the last; and so on,

until we come as near to unity as the number of figures chosen will permit.

Multiply all the results together, and divide 2 by the product: the

quotient is an approximation to the circumference when the diameter is

unity. Taking aim at four figures, that is, working to five figures to

secure accuracy in the fourth, we have .70712 for the square root of 1/2;

.92390 for the square root of half one more than .70712; and so on, through

.98080, .99520, .99880, .99970, .99992, .99998. The product of the eight

results is .63667; divide 2 by this, and the quotient is 3.1413..., of

which four figures are correct. Had the product been .636363... instead of

.63667..., the famous result of Archimedes, 22-7ths, would have been

accurately true. It is singular that no cyclometer maintains that

Archimedes hit it exactly.

A literary journal could hardly admit as much as the preceding, if it stood

alone. But in my present undertaking it passes as the halfpennyworth of

bread to many gallons of sack. Many more methods might be given, all ending

in the same result, let that result mean what it may.

Now since dozens of methods, to which dozens more might be added at

pleasure, concur in giving one and the same result; and since these methods

are declared by all who have shown knowledge of mathematics to be

_demonstrated_: it is not asking too much of a person who has just a little

knowledge of the first elements that he should learn more, and put his hand

upon the error, before he intrudes his assertion of the existence of error

upon those who have given more time and attention to it than himself, and

who are in possession, over and above many demonstrations, of many

consequences verifying each other, of which he can know nothing. This is

all that is required. Let any one square the circle, and persuade his

friends, if he and they please: let him print, and let all read who choose.

But let him abstain from intruding himself upon those who have been

satisfied by existing demonstration, until he is prepared {214} to lay his

finger on the point in which existing demonstration is wrong. Let him also

say what this mysterious 3.14159... really is, which comes in at every door

and window, and down every chimney, calling itself the circumference to a

unit of diameter. This most impudent and successful impostor holds false

title-deeds in his hands, and invites examination: surely those who can

find out the rightful owner are equally able to detect the forgery. All the

quadrators are agreed that, be the right what it may, 3.14159... is wrong.

It would be well if they would put their heads together, and say what this

wrong result really means. The mathematicians of all ages have tried all

manner of processes, with one object in view, and by methods which are

admitted to yield demonstration in countless cases. They have all arrived

at one result. A large number of opponents unite in declaring this result

wrong, and all agree in two points: first, in differing among themselves;

secondly, in declining to point out what that curious result really is

which the mathematical methods all agree in giving.

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. The general run of circle-squarers, hearing that

the quadrature is not pronounced to be _demonstratively_ impossible,

imagine that the _arithmetical_ quadrature is open to their ingenuity.

Before attempting the arithmetical problem, they ought to acquire knowledge

enough to read Lambert's[355] demonstration (last given in Brewster's[356]

translation {215} of Legendre's[357] Geometry) and, if they can, to refute

it. [It will be given in an Appendix.] Probably some have begun this way,

and have caught a Tartar who has refused to let them go: I have never heard

of any one who, in producing his own demonstration, has laid his finger on

the faulty part of Lambert's investigation. This is the answer to those who

think that the mathematicians treat the arithmetical squarers too lightly,

and that as some person may succeed at last, all attempts should be

examined. Those who have so thought, not knowing that there is

demonstration on the point, will probably admit that a person who

contradicts a theorem of which the demonstration has been acknowledged for

a century by all who have alluded to it as read by themselves, may

reasonably be required to point out the error before he demands attention

to his own result.

_Apopempsis of the Tutelaries._--Again and again I am told that I spend too

much time and trouble upon my two tutelaries: but when I come to my

summing-up I shall make it appear that I have a purpose. Some say I am too

hard upon them: but this is quite a mistake. Both of them beat little

Oliver himself in the art and science of asking for more; but without

Oliver's excuse, for I had given good allowance. Both began with me, not I

with them: and both knew what they had to expect when they applied for a

second helping.

On July 31, the Monday after the publication of my remarks on my 666

correspondent, I found _three_ notes in separate envelopes, addressed to me

at "7A, University College." When I saw the three new digits I was taken

rhythmopoetic, as follows--

Here's the Doctor again with his figs, and by Heavens!

He was always at sixes, and now he's at sevens.

To understand this fully the reader must know that the greater part of

Apocalyptic interpretation has long been condensed, in my mind, into the

Turkish street-cry--In the {216} name of the Prophet! figs! I make a few

extracts. The reader will observe that Dr. Thorn grumbles at his _private_

letters being _publicly_ ridiculed. A man was summoned for a glutolactic

assault; he complained of the publication of his proceeding: I kicked etc.

_in confidence_, he said.

"After reading your last, which tries in every way to hold me up to public

ridicule for daring to write you privately ['that you would be d----d,'

omitted by accident] one would say, Why have anything to do with such a

testy person? [Wrong word; no testy person can manage cool and consecutive

ridicule. Quaere, what is this word? Is it anything but a corruption of the

obsolete word _tetchy_ of the same meaning? Some think _touchy_ is our

modern form of _tetchy_, which I greatly doubt]. My answer is, the poor man

is lamentably ignorant; he is not only so, but 'out of the way' [quite

true; my readers know me by this time for an out-of-the-way person. What

other could tackle my squad of paradoxers? What other would undertake the

job?] Can he be brought back and form one of those who in Ezekiel 37 ch.

have the Spirit breathed into them and live.... Have I any other feeling

towards you except that of peace and goodwill? [Not to your distinct

knowledge; but in all those who send people to 'the other place' for

contempt of their interpretations, there is a lurking wish which is father

to the thought; 'you _will_ be d----d' and 'you _be_ d--d' are Siamese

twins]. Of course your sneer at 666 brought plain words; but when men

meddle with what they do not understand (not having the double _Vahu_) they

must be dealt with faithfully by those who do.... [They must; which

justifies the Budget of Paradoxes: but no occasion to send them anywhere;

no preachee and floggee too, as the negro said]. Many will find the text

Prov. i. 26 fully realized. [All this contains distinct assumption of a

right 'of course' to declare accursed those who do not respect the writer's

vagary].... If I could but get the [Hebrew: A], the Ox-head, which in Old

Hebrew was just the Latin Digamma, F, out {217} of your name, and could

then Thau you with the Thau of Ezekiel ix, 4, the [chi], then you would

bear the number of a man! But this is too hard for me, although not so for

the Lord! Jer. xxxii. 17.... And now a word: is ridicule the right thing in

so solemn a matter as the discussion of Holy Writ? [Is food for ridicule

the right thing? Did I discuss Holy Writ? I did not: I concussed profane

scribble. Even the Doctor did not _discuss_; he only enunciated and

denunciated out of the mass of inferences which a mystical head has found

premises for in the Bible]."

M 40

O 70

R 100

G 6

N 50

----

266

[Hebrew: t]=[chi] 400

[That ill opinions are near relations of ill wishes, will be detected by

those who are on the look out. The following was taken down in a Scotch

Church by Mr. Cobden,[358] who handed it to a Roman friend of mine, for his

delectation (in 1855): "Lord, we thank thee that thou hast brought the Pope

into trouble; and we pray that thou wouldst be mercifully pleased to

increase the same."]

Here is a martyr who quarrels with his crown; a missionary who reviles his

persecutor: send him to New Zealand, and he would disagree with the Maoris

who ate him. Man of unilateral reciprocity! have you, who write to a

stranger with hints that that stranger and his wife are children of

perdition, the bad taste to complain of a facer in return? As James

Smith[359]--the Attorney-wit, not the Dock-cyclometer--said, or nearly

said,

"A pretty thing, forsooth!

Is he to burn, all scalding hot,

Me and my wife, and am I not

To job him out a tooth?"

{218}

Those who think parody vulgar will be pleased to substitute for the above a

quotation from Butler[360]:--

"There's nothing so absurd or vain

Or barbarous or inhumane,

But if it lay the least pretence

To piety and godliness,

Or tender-hearted conscience,

And zeal for gospel truths profess,--

Does sacred instantly commence,

And all that dare but question it are straight

Pronounced th' uncircumcised and reprobate,

As malefactors that escape and fly

Into a sanctuary for defence,

Must not be brought to justice thence,

Although their crimes be ne'er so great and high.

And he that dares presume to do't

Is sentenced and delivered up

To Satan that engaged him to't."

A Budget of Paradoxes, Volume II · 第 75 / 123 题