CHAPTER XVI

ARITHMETIC

=1601.= There is no problem in all mathematics that cannot be

solved by direct counting. But with the present implements of

mathematics many operations can be performed in a few minutes

which without mathematical methods would take a lifetime.

--MACH, ERNST.

_Popular Scientific Lectures [McCormack]

(Chicago, 1898), p. 197._

=1602.= There is no inquiry which is not finally reducible to a

question of Numbers; for there is none which may not be conceived

of as consisting in the determination of quantities by each

other, according to certain relations.--COMTE, A.

_Positive Philosophy [Martineau], Bk. 1,

chap. 1._

=1603.= Pythagoras says that number is the origin of all things,

and certainly the law of number is the key that unlocks the

secrets of the universe. But the law of number possesses an

immanent order, which is at first sight mystifying, but on a more

intimate acquaintance we easily understand it to be intrinsically

necessary; and this law of number explains the wondrous

consistency of the laws of nature.--CARUS, PAUL.

_Reflections on Magic Squares; Monist,

Vol. 16 (1906), p. 139._

=1604.= An ancient writer said that arithmetic and geometry are

the _wings of mathematics_; I believe one can say without

speaking metaphorically that these two sciences are the

foundation and essence of all the sciences which deal with

quantity. Not only are they the foundation, they are also, as it

were, the capstones; for, whenever a result has been arrived at,

in order to use that result, it is necessary to translate it into

numbers or into lines; to translate it into numbers requires the

aid of arithmetic, to translate it into lines necessitates the

use of geometry.--LAGRANGE.

_Leçons Elémentaires sur les

Mathématiques, Leçon seconde._

=1605.= It is number which regulates everything and it is measure

which establishes universal order.... A quiet peace, an

inviolable order, an inflexible security amidst all change and

turmoil characterize the world which mathematics discloses and

whose depths it unlocks.--DILLMANN, E.

_Die Mathematik die Fackelträgerin einer

neuen Zeit (Stuttgart, 1889), p. 12._

=1606.=

Number, the inducer of philosophies,

The synthesis of letters, ....

--AESCHYLUS.

_Quoted in, Thomson, J. A., Introduction

to Science, chap. 1 (London)._

=1607.= Amongst all the ideas we have, as there is none suggested

to the mind by more ways, so there is none more simple, than that

of _unity_, or one: it has no shadow of variety or composition in

it; every object our senses are employed about; every idea in our

understanding; every thought of our minds, brings this idea along

with it. And therefore it is the most intimate to our thoughts,

as well as it is, in its agreement to all other things, _the most

universal idea we have_.--LOCKE, JOHN.

_An Essay concerning Human

Understanding, Bk. 2, chap. 16, sect.

1._

=1608.= The _simple modes_ of _number_ are of all other the most

distinct; every the least variation, which is an unit, making

each combination as clearly different from that which approacheth

nearest to it, as the most remote; two being as distinct from

one, as two hundred; and the idea of two as distinct from the

idea of three, as the magnitude of the whole earth is from that

of a mite.--LOCKE, JOHN.

_An Essay concerning Human

Understanding, Bk. 2, chap. 16, sect.

3._

=1609.= The number of a class is the class of all classes similar

to the given class.--RUSSELL, BERTRAND.

_Principles of Mathematics (Cambridge,

1903), p. 115._

=1610.= Number is that property of a group of distinct things

which remains unchanged during any change to which the group may

be subjected which does not destroy the distinctness of the

individual things.--FINE, H. B.

_Number-system of Algebra (Boston and

New York, 1890), p. 3._

=1611.= The science of arithmetic may be called the science of

exact limitation of matter and things in space, force, and time.

--PARKER, F. W.

_Talks on Pedagogics (New York, 1894),

p. 64._

=1612.=

Arithmetic is the science of the Evaluation

of Functions,

Algebra is the science of the Transformation

of Functions.

--HOWISON, G. H.

_Journal of Speculative Philosophy, Vol.

5, p. 175._

=1613.= That _arithmetic_ rests on pure intuition of _time_ is not

so obvious as that geometry is based on pure intuition of space,

but it may be readily proved as follows. All counting consists in

the repeated positing of unity; only in order to know how often it

has been posited, we mark it each time with a different word:

these are the numerals. Now repetition is possible only through

succession: but succession rests on the immediate intuition of

_time_, it is intelligible only by means of this latter concept:

hence counting is possible only by means of time.--This dependence

of counting on _time_ is evidenced by the fact that in all

languages multiplication is expressed by “times” [mal], that

is, by a concept of time; sexies, ἑξακις, six fois, six times.

--SCHOPENHAUER, A.

_Die Welt als Vorstellung und Wille;

Werke (Frauenstaedt) (Leipzig, 1877),

Bd. 3, p. 39._

=1614.= The miraculous powers of modern calculation are due to

three inventions: the Arabic Notation, Decimal Fractions and

Logarithms.--CAJORI, F.

_History of Mathematics (New York,

1897), p. 161._

=1615.= The grandest achievement of the Hindoos and the one

which, of all mathematical investigations, has contributed most

to the general progress of intelligence, is the invention of the

principle of position in writing numbers.--CAJORI, F.

_History of Mathematics (New York,

1897), p. 87._

=1616.= The invention of logarithms and the calculation of the

earlier tables form a very striking episode in the history of

exact science, and, with the exception of the _Principia_ of

Newton, there is no mathematical work published in the country

which has produced such important consequences, or to which so

much interest attaches as to Napier’s Descriptio.

--GLAISHER, J. W. L.

_Encyclopedia Britannica, 9th Edition;

Article “Logarithms.”_

=1617.= All minds are equally capable of attaining the science of

numbers: yet we find a prodigious difference in the powers of

different men, in that respect, after they have grown up, because

their minds have been more or less exercised in it.

--JOHNSON, SAMUEL.

_Boswell’s Life of Johnson, Harper’s

Edition (1871), Vol. 2, p. 33._

=1618.= The method of arithmetical teaching is perhaps the best

understood of any of the methods concerned with elementary

studies.--BAIN, ALEXANDER.

_Education as a Science (New York,

1898), p. 288._

=1619.= What a benefite that onely thyng is, to haue the witte

whetted and sharpened, I neade not trauell to declare, sith all

men confesse it to be as greate as maie be. Excepte any witlesse

persone thinke he maie bee to wise. But he that most feareth

that, is leaste in daunger of it. Wherefore to conclude, I see

moare menne to acknowledge the benefite of nomber, than I can

espie willying to studie, to attaine the benefites of it. Many

praise it, but fewe dooe greatly practise it: onlesse it bee for

the vulgare practice, concernying Merchaundes trade. Wherein the

desire and hope of gain, maketh many willying to sustaine some

trauell. For aide of whom, I did sette forth the first parte of

_Arithmetike_. But if thei knewe how faree this seconde parte,

doeeth excell the firste parte, thei would not accoumpte any

tyme loste, that were emploied in it. Yea thei would not thinke

any tyme well bestowed till thei had gotten soche habilitie by

it, that it might be their aide in al other studies.

--RECORDE, ROBERT.

_Whetstone of Witte (London, 1557)._

=1620.= You see then, my friend, I observed, that our real need

of this branch of science [arithmetic] is probably because it

seems to compel the soul to use our intelligence in the search

after pure truth.

Aye, remarked he, it does this to a remarkable extent.

Have you ever noticed that those who have a turn for arithmetic

are, with scarcely an exception, naturally quick in all sciences;

and that men of slow intellect, if they be trained and exercised

in this study ... become invariably quicker than they were

before?

Exactly so, he replied.

And, moreover, I think you will not easily find that many things

give the learner and student more trouble than this.

Of course not.

On all these accounts, then, we must not omit this branch of

science, but those with the best of talents should be instructed

therein.--PLATO.

_Republic [Davis], Bk. 7, chap. 8._

=1621.= Arithmetic has a very great and elevating effect,

compelling the soul to reason about abstract number, and if

visible or tangible objects are obtruding upon the argument,

refusing to be satisfied.--PLATO.

_Republic [Jowett], Bk. 7, p. 525._

=1622.= Good arithmetic contributes powerfully to purposive

effort, to concentration, to tenacity of purpose, to generalship,

to faith in right, and to the joy of achievement, which are the

elements that make up efficient citizenship.... Good arithmetic

exalts thinking, furnishes intellectual pleasure, adds appreciably

to love of right, and subordinates pure memory.--MYERS, GEORGE.

_Monograph on Arithmetic in Public

Education (Chicago), p. 21._

=1623.= On the one side we may say that the purpose of number

work is to put a child in possession of the machinery of

calculation; on the other side it is to give him a better mastery

of the world through a clear (mathematical) insight into the

varied physical objects and activities. The whole world, from one

point of view, can be definitely interpreted and appreciated by

mathematical measurements and estimates. Arithmetic in the common

school should give a child this point of view, the ability to see

and estimate things with a mathematical eye.--MCMURRAY, C. A.

_Special Method in Arithmetic_ (_New

York, 1906_), _p. 18._

=1624.= We are so accustomed to hear arithmetic spoken of as

one of the three fundamental ingredients in all schemes of

instruction, that it seems like inquiring too curiously to ask

why this should be. Reading, Writing, and Arithmetic--these

three are assumed to be of co-ordinate rank. Are they indeed

co-ordinate, and if so on what grounds?

In this modern “trivium” the art of reading is put first. Well,

there is no doubt as to its right to the foremost place. For

reading is the instrument of all our acquisition. It is

indispensable. There is not an hour in our lives in which it does

not make a great difference to us whether we can read or not.

And the art of Writing, too; that is the instrument of all

communication, and it becomes, in one form or other, useful to us

every day. But Counting--doing sums,--how often in life does this

accomplishment come into exercise? Beyond the simplest additions,

and the power to check the items of a bill, the arithmetical

knowledge required of any well-informed person in private life is

very limited. For all practical purposes, whatever I may have

learned at school of fractions, or proportion, or decimals, is,

unless I happen to be in business, far less available to me in

life than a knowledge, say, of history of my own country, or the

elementary truths of physics. The truth is, that regarded as

practical _arts_, reading, writing, and arithmetic have no right

to be classed together as co-ordinate elements of education; for

the last of these is considerably less useful to the average man

or woman not only than the other two, but than many others that

might be named. But reading, writing, and such mathematical or

logical exercise as may be gained in connection with the

manifestation of numbers, _have_ a right to constitute the

primary elements of instruction. And I believe that arithmetic,

if it deserves the high place that it conventionally holds in our

educational system, deserves it mainly on the ground that it is

to be treated as a logical exercise. It is the only branch of

mathematics which has found its way into primary and early

education; other departments of pure science being reserved for

what is called higher or university instruction. But all the

arguments in favor of teaching algebra and trigonometry to

advanced students, apply equally to the teaching of the

principles or theory of arithmetic to schoolboys. It is

calculated to do for them exactly the same kind of service, to

educate one side of their minds, to bring into play one set of

faculties which cannot be so severely or properly exercised in

any other department of learning. In short, relatively to the

needs of a beginner, Arithmetic, as a science, is just as

valuable--it is certainly quite as intelligible--as the higher

mathematics to a university student.--FITCH, J. G.

_Lectures on Teaching (New York, 1906),

pp. 267-268._

=1625.= What mathematics, therefore are expected to do for the

advanced student at the university, Arithmetic, if taught

demonstratively, is capable of doing for the children even of the

humblest school. It furnishes training in reasoning, and

particularly in deductive reasoning. It is a discipline in

closeness and continuity of thought. It reveals the nature of

fallacies, and refuses to avail itself of unverified assumptions.

It is the one department of school-study in which the sceptical

and inquisitive spirit has the most legitimate scope; in which

authority goes for nothing. In other departments of instruction

you have a right to ask for the scholar’s confidence, and to

expect many things to be received on your testimony with

the understanding that they will be explained and verified

afterwards. But here you are justified in saying to your pupil

“Believe nothing which you cannot understand. Take nothing for

granted.” In short, the proper office of arithmetic is to serve

as elementary training in logic. All through your work as

teachers you will bear in mind the fundamental difference between

knowing and thinking; and will feel how much more important

relatively to the health of the intellectual life the habit of

thinking is than the power of knowing, or even facility of

achieving visible results. But here this principle has special

significance. It is by Arithmetic more than by any other subject

in the school course that the art of thinking--consecutively,

closely, logically--can be effectually taught.--FITCH, J. G.

_Lectures on Teaching (New York, 1906),

pp. 292-293._

=1626.= Arithmetic and geometry, those wings on which the

astronomer soars as high as heaven.--BOYLE, ROBERT.

_Usefulness of Mathematics to Natural

Philosophy; Works (London, 1772), Vol.

3, p. 429._

=1627.= Arithmetical symbols are written diagrams and geometrical

figures are graphic formulas.--HILBERT, D.

_Mathematical Problems; Bulletin

American Mathematical Society, Vol. 8

(1902), p. 443._

=1628.= Arithmetic and geometry are much more certain than the

other sciences, because the objects of them are in themselves so

simple and so clear that they need not suppose anything which

experience can call in question, and both proceed by a chain of

consequences which reason deduces one from another. They are also

the easiest and clearest of all the sciences, and their object is

such as we desire; for, except for want of attention, it is

hardly supposable that a man should go astray in them. We must

not be surprised, however, that many minds apply themselves by

preference to other studies, or to philosophy. Indeed everyone

allows himself more freely the right to make his guess if the

matter be dark than if it be clear, and it is much easier to have

on any question some vague ideas than to arrive at the truth

itself on the simplest of all.--DESCARTES.

_Rules for the Direction of the Mind;

Torrey’s Philosophy of Descartes (New

York, 1892), p. 63._

=1629.=

Why are _wise_ few, _fools_ numerous in the

excesse?

’Cause, wanting _number_, they are

_numberlesse_.

--LOVELACE.

_Noah Bridges: Vulgar Arithmetike

(London, 1659), p. 127._

=1630.= The clearness and distinctness of each mode of number

from all others, even those that approach nearest, makes me apt

to think that demonstrations in numbers, if they are not more

evident and exact than in extension, yet they are more general in

their use, and more determinate in their application. Because the

ideas of numbers are more precise and distinguishable than in

extension; where every equality and excess are not so easy to be

observed or measured; because our thoughts cannot in space arrive

at any determined smallness beyond which it cannot go, as an

unit; and therefore the quantity or proportion of any the least

excess cannot be discovered.--LOCKE, JOHN.

_An Essay concerning Human

Understanding, Bk. 2, chap. 16, sect.

4._

=1631.= Battalions of figures are like battalions of men, not

always as strong as is supposed.--SAGE, M.

_Mrs. Piper and the Society for

Psychical Research [Robertson] (New

York, 1909), p. 151._

=1632.= Number was born in superstition and reared in mystery,...

numbers were once made the foundation of religion and philosophy, and

the tricks of figures have had a marvellous effect on a credulous

people.--PARKER, F. W.

_Talks on Pedagogics (New York, 1894),

P. 64._

=1633.= A rule to trick th’ arithmetic.--KIPLING, R.

_To the True Romance._

=1634.= God made integers, all else is the work of man.

--KRONECKER, L.

_Jahresberichte der Deutschen

Mathematiker Vereinigung, Bd. 2, p. 19._

=1635.= Plato said “ἀεὶ ὁ θεὸς γεωμέτρε.” Jacobi changed this to

“ἀεὶ ὁ θεὸς ἀριθμητίζει.” Then came Kronecker and created the

memorable expression “Die ganzen Zahlen hat Gott gemacht, alles

andere ist Menschenwerk.”--KLEIN, F.

_Jahresbericht der Deutschen

Mathematiker Vereinigung, Bd. 6, p.

136._

=1636.= Integral numbers are the fountainhead of all mathematics.

--MINKOWSKI, H.

_Diophantische Approximationen (Leipzig,

1907), Vorrede._

=1637.= The “Disquisitiones Arithmeticae” that great book with

seven seals.--MERZ, J. T.

_A History of European Thought in the

Nineteenth Century (Edinburgh and

London, 1908), p. 721._

=1638.= It may fairly be said that the germs of the modern

algebra of linear substitutions and concomitants are to be found

in the fifth section of the _Disquisitiones Arithmeticae_; and

inversely, every advance in the algebraic theory of forms is an

acquisition to the arithmetical theory.--MATHEWS, G. B.

_Theory of Numbers (Cambridge, 1892),

Part 1, sect. 48._

=1639.= Strictly speaking, the theory of numbers has nothing to

do with negative, or fractional, or irrational quantities, _as

such._ No theorem which cannot be expressed without reference to

these notions is purely arithmetical: and no proof of an

arithmetical theorem, can be considered finally satisfactory if

it intrinsically depends upon extraneous analytical theories.

--MATHEWS, G. B.

_Theory of Numbers (Cambridge, 1892),

Part 1, sect. 1._

=1640.= Many of the greatest masters of the mathematical sciences

were first attracted to mathematical inquiry by problems relating

to numbers, and no one can glance at the periodicals of the

present day which contain questions for solution without noticing

how singular a charm such problems still continue to exert. The

interest in numbers seems implanted in the human mind, and it is

a pity that it should not have freer scope in this country. The

methods of the theory of numbers are peculiar to itself, and are

not readily acquired by a student whose mind has for years been

familiarized with the very different treatment which is

appropriate to the theory of continuous magnitude; it is

therefore extremely desirable that some portion of the theory

should be included in the ordinary course of mathematical

instruction at our University. From the moment that Gauss, in his

wonderful treatise of 1801, laid down the true lines of the

theory, it entered upon a new day, and no one is likely to be

able to do useful work in any part of the subject who is

unacquainted with the principles and conceptions with which he

endowed it.--GLAISHER, J. W. L.

_Presidential Address British

Association for the Advancement of

Science (1890); Nature, Vol. 42, p.

467._

=1641.= Let us look for a moment at the general significance of

the fact that calculating machines actually exist, which relieve

mathematicians of the purely mechanical part of numerical

computations, and which accomplish the work more quickly and with

a greater degree of accuracy; for the machine is not subject to

the slips of the human calculator. The existence of such a

machine proves that computation is not concerned with the

significance of numbers, but that it is concerned essentially

only with the formal laws of operation; for it is only these that

the machine can obey--having been thus constructed--an intuitive

perception of the significance of numbers being out of the

question.--KLEIN, F.

_Elementarmathematik vom höheren

Standpunkte aus. (Leipzig, 1908), Bd. 1,

p. 53._

=1642.= Mathematics is the queen of the sciences and arithmetic

the queen of mathematics. She often condescends to render service

to astronomy and other natural sciences, but in all relations she

is entitled to the first rank.--GAUSS.

_Sartorius von Waltershausen: Gauss zum

Gedächtniss. (Leipzig, 1866), p. 79._

=1643.=

Zu Archimedes kam ein wissbegieriger Jüngling,

Weihe mich, sprach er zu ihm, ein in die

göttliche Kunst,

Die so herrliche Dienste der Sternenkunde

geleistet,

Hinter dem Uranos noch einen Planeten entdeckt.

Göttlich nennst Du die Kunst, sie ist’s,

versetzte der Weise,

Aber sie war es, bevor noch sie den Kosmos

erforscht,

Ehe sie herrliche Dienste der Sternenkunde

geleistet,

Hinter dem Uranos noch einen Planeten entdeckt.

Was Du im Kosmos erblickst, ist nur der

Göttlichen Abglanz,

In der Olympier Schaar thronet die ewige

Zahl.

--JACOBI, C. G. J.

_Journal für Mathematik, Bd. 101 (1887),

p. 338._

To Archimedes came a youth intent upon

knowledge,

Quoth he, “Initiate me into the science divine

Which to astronomy, lo! such excellent service

has rendered,

And beyond Uranus’ orb a hidden planet

revealed.”

“Call’st thou the science divine? So it is,”

the wise man responded,

“But so it was long before its light on the

Cosmos it shed,

Ere in astronomy’s realm such excellent service

it rendered,

And beyond Uranus’ orb a hidden planet

revealed.

Only reflection divine is that which Cosmos

discloses,

Number herself sits enthroned among Olympia’s

hosts.”

=1644.= The higher arithmetic presents us with an inexhaustible

store of interesting truths,--of truths too, which are not

isolated, but stand in a close internal connexion, and between

which, as our knowledge increases, we are continually discovering

new and sometimes wholly unexpected ties. A great part of its

theories derives an additional charm from the peculiarity that

important propositions, with the impress of simplicity upon them,

are often easily discoverable by induction, and yet are of so

profound a character that we cannot find their demonstration

till after many vain attempts; and even then, when we do succeed,

it is often by some tedious and artificial process, while the

simpler methods may long remain concealed.--GAUSS, C. F.

_Preface to Eisenstein’s Mathematische

Abhandlungen (Berlin, 1847), [H. J. S.

Smith]._

=1645.= The Theory of Numbers has acquired a great and increasing

claim to the attention of mathematicians. It is equally

remarkable for the number and importance of its results, for the

precision and rigorousness of its demonstrations, for the variety

of its methods, for the intimate relations between truths

apparently isolated which it sometimes discloses, and for the

numerous applications of which it is susceptible in other parts

of analysis.--SMITH, H. J. S.

_Report on the Theory of Numbers,

British Association, 1859; Collected

Mathematical Papers, Vol. 1, p. 38._

=1646.= The invention of the symbol ≡ by Gauss affords a striking

example of the advantage which may be derived from an appropriate

notation, and marks an epoch in the development of the science of

arithmetic.--MATHEWS, G. B.

_Theory of Numbers (Cambridge, 1892),

Part 1, sect. 29._

=1647.= As Gauss first pointed out, the problem of cyclotomy, or

division of the circle into a number of equal parts, depends in a

very remarkable way upon arithmetical considerations. We have

here the earliest and simplest example of those relations of the

theory of numbers to transcendental analysis, and even to pure

geometry, which so often unexpectedly present themselves, and

which, at first sight, are so mysterious.--MATHEWS, G. B.

_Theory of Numbers (Cambridge, 1892),

Part 1, sect. 167._

=1648.= I have sometimes thought that the profound mystery which

envelops our conceptions relative to prime numbers depends upon

the limitations of our faculties in regard to time, which like

space may be in its essence poly-dimensional, and that this and

such sort of truths would become self-evident to a being

whose mode of perception is according to _superficially_ as

distinguished from our own limitation to _linearly_ extended

time.--SYLVESTER, J. J.

_Collected Mathematical Papers, Vol. 4,

p. 600, footnote._

CHAPTER XVII

ALGEBRA

=1701.= The science of algebra, independently of any of its uses,

has all the advantages which belong to mathematics in general as

an object of study, and which it is not necessary to enumerate.

Viewed either as a science of quantity, or as a language of

symbols, it may be made of the greatest service to those who are

sufficiently acquainted with arithmetic, and who have sufficient

power of comprehension to enter fairly upon its difficulties.

--DE MORGAN, A.

_Elements of Algebra (London, 1837),

Preface._

=1702.= Algebra is generous, she often gives more than is asked

of her.--D’ALEMBERT.

_Quoted in Bulletin American Mathematical

Society, Vol. 2 (1905), p. 285._

=1703.= The operations of symbolic arithmetick seem to me to

afford men one of the clearest exercises of reason that I ever

yet met with, nothing being there to be performed without strict

and watchful ratiocination, and the whole method and progress of

that appearing at once upon the paper, when the operation is

finished, and affording the analyst a lasting, and, as it were,

visible ratiocination.--BOYLE, ROBERT.

_Works (London, 1772), Vol. 3, p. 426._

=1704.= The human mind has never invented a labor-saving machine

equal to algebra.--

_The Nation, Vol. 33, p. 237._

=1705.= They that are ignorant of Algebra cannot imagine the

wonders in this kind are to be done by it: and what further

improvements and helps advantageous to other parts of knowledge

the sagacious mind of man may yet find out, it is not easy to

determine. This at least I believe, that the _ideas of quantity_

are not those alone that are capable of demonstration and

knowledge; and that other, and perhaps more useful, parts of

contemplation, would afford us certainty, if vices, passions, and

domineering interest did not oppose and menace such endeavours.

--LOCKE, JOHN.

_An Essay concerning Human Understanding, Bk.

4, chap. 3, sect. 18._

=1706.= Algebra is but written geometry and geometry is but

figured algebra.--GERMAIN, SOPHIE.

_Mémoire sur la surfaces élastiques._

=1707.= So long as algebra and geometry proceeded separately

their progress was slow and their application limited, but when

these two sciences were united, they mutually strengthened each

other, and marched together at a rapid pace toward perfection.

--LAGRANGE.

_Leçons élémentaires sur les Mathématiques,

Leçon Cinquième._

=1708.= The laws of algebra, though suggested by arithmetic, do

not depend on it. They depend entirely on the conventions by

which it is stated that certain modes of grouping the symbols are

to be considered as identical. This assigns certain properties to

the marks which form the symbols of algebra. The laws regulating

the manipulation of algebraic symbols are identical with those of

arithmetic. It follows that no algebraic theorem can ever

contradict any result which could be arrived at by arithmetic;

for the reasoning in both cases merely applies the same general

laws to different classes of things. If an algebraic theorem can

be interpreted in arithmetic, the corresponding arithmetical

theorem is therefore true.--WHITEHEAD, A. N.

_Universal Algebra (Cambridge, 1898), p. 2._

=1709.= That a formal science like algebra, the creation of our

abstract thought, should thus, in a sense, dictate the laws of

its own being, is very remarkable. It has required the experience

of centuries for us to realize the full force of this appeal.

--MATHEWS, G. B.

_F. Spencer: Chapters on Aims and Practice of

Teaching (London, 1899), p. 184._

=1710.= The rules of algebra may be investigated by its own

principles, without any aid from geometry; and although in many

cases the two sciences may serve to illustrate each other, there

is not now the least necessity in the more elementary parts to

call in the aid of the latter in expounding the former.

--CHRYSTAL, GEORGE.

_Encyclopedia Britannica, 9th Edition;

Article “Algebra.”_

=1711.= Algebra, as an art, can be of no use to any one in the

business of life; certainly not as taught in the schools. I

appeal to every man who has been through the school routine

whether this be not the case. Taught as an art it is of little

use in the higher mathematics, as those are made to feel who

attempt to study the differential calculus without knowing more

of the principles than is contained in books of rules.

--DE MORGAN, A.

_Elements of Algebra (London, 1837),

Preface._

=1712.= We may always depend upon it that algebra, which cannot

be translated into good English and sound common sense, is bad

algebra.--CLIFFORD, W. K.

_Common Sense in the Exact Sciences (London,

1885), chap. 1, sect. 7._

=1713.= The best review of arithmetic consists in the study of

algebra.--CAJORI, F.

_Teaching and History of Mathematics in U. S.

(Washington, 1896), p. 110._

=1714.= [Algebra] has for its object the resolution of equations;

taking this expression in its full logical meaning, which

signifies the transformation of implicit functions into

equivalent explicit ones. In the same way arithmetic may be

defined as destined to the determination of the values of

functions.... We will briefly say that _Algebra is the Calculus

of Functions_, and _Arithmetic the Calculus of Values_.--COMTE, A.

_Philosophy of Mathematics [Gillespie] (New

York, 1851), p. 55._

=1715.= ... the subject matter of algebraic science is the

abstract notion of time; divested of, or not yet clothed with,

any actual knowledge which we may possess of the real Events of

History, or any conception which we may frame of Cause and Effect

in Nature; but involving, what indeed it _cannot_ be divested of,

the thought of _possible_ Succession, or of pure, _ideal_

Progression.--HAMILTON, W. R.

_Graves’ Life of Hamilton (New York,

1882-1889), Vol. 3, p. 633._

=1716.= ... instead of seeking to attain consistency and

uniformity of system, as some modern writers have attempted, by

banishing this thought of time from the _higher_ Algebra, I seek

to _attain_ the same object, by systematically introducing it

into the _lower_ or earlier parts of the science.--HAMILTON, W. R.

_Graves’ Life of Hamilton (New York,

1882-1889), Vol. 3, p. 634._

=1717.= The circumstances that algebra has its origin in

arithmetic, however widely it may in the end differ from that

science, led Sir Isaac Newton to designate it “Universal

Arithmetic,” a designation which, vague as it is, indicates its

character better than any other by which it has been attempted to

express its functions--better certainly, to ordinary minds, than

the designation which has been applied to it by Sir William Rowan

Hamilton, one of the greatest mathematicians the world has seen

since the days of Newton--“the Science of Pure Time;” or even

than the title by which De Morgan would paraphrase Hamilton’s

words--“the Calculus of Succession.”--CHRYSTAL, GEORGE.

_Encyclopedia Britannica, 9th Edition;

Article “Algebra.”_

=1718.= Time is said to have only _one dimension_, and space to

have _three dimensions_.... The mathematical _quaternion_

partakes of _both_ these elements; in technical language it may

be said to be “time plus space,” or “space plus time:” and in

this sense it has, or at least involves a reference to, _four

dimensions_....

And how the One of Time, of Space the Three,

Might in the Chain of Symbols girdled be.

--HAMILTON, W. R.

_Graves’ Life of Hamilton (New York,

1882-1889), Vol. 3, p. 635._

=1719.= It is confidently predicted, by those best qualified to

judge, that in the coming centuries Hamilton’s Quaternions will

stand out as the great discovery of our nineteenth century. Yet

how silently has the book taken its place upon the shelves of the

mathematician’s library! Perhaps not fifty men on this side of

the Atlantic have seen it, certainly not five have read it.

--HILL, THOMAS.

_North American Review, Vol. 85, p.

223._

=1720.= I think the time may come when double algebra will be the

beginner’s tool; and quaternions will be where double algebra is

now. The Lord only knows what will come above the quaternions.

--DE MORGAN, A.

_Graves’ Life of Hamilton (New York,

1882-1889), Vol. 3, p. 493._

=1721.= Quaternions came from Hamilton after his really good work

had been done; and though beautifully ingenious, have been an

unmixed evil to those who have touched them in any way, including

Clerk Maxwell.--THOMSON, WILLIAM.

_Thompson, S. P.: Life of Lord Kelvin

(London, 1910), p. 1138._

=1722.= The whole affair [quaternions] has in respect to

mathematics a value not inferior to that of “Volapuk” in respect

to language.--THOMSON, WILLIAM.

_Thompson, S. P.: Life of Lord Kelvin

(London, 1910), p. 1138._

=1723.= A quaternion of maladies! Do send me some formula by help

of which I may so doctor them that they may all become imaginary

or positively equal to nothing.--SEDGWICK.

_Graves’ Life of Hamilton (New York,

1882-1889), Vol. 3, p. 2._

=1724.= If nothing more could be said of Quaternions than that

they enable us to exhibit in a singularly compact and elegant

form, whose meaning is obvious at a glance on account of the

utter inartificiality of the method, results which in the

ordinary Cartesian co-ordinates are of the utmost complexity, a

very powerful argument for their use would be furnished. But it

would be unjust to Quaternions to be content with such a

statement; for we are fully entitled to say that in _all_ cases,

even in those to which the Cartesian methods seem specially

adapted, they give as simple an expression as any other method;

while in the great majority of cases they give a vastly simpler

one. In the common methods a judicious choice of co-ordinates is

often of immense importance in simplifying an investigation; in

Quaternions there is usually _no choice_, for (except when they

degrade to mere scalars) they are in general utterly independent

of any particular directions in space, and select of themselves

the most natural reference lines for each particular problem.

--TAIT, P. G.

_Presidential Address British

Association for the Advancement of

Science (1871); Nature, Vol. 4, p. 270._

=1725.= Comparing a Quaternion investigation, no matter in what

department, with the equivalent Cartesian one, even when the

latter has availed itself to the utmost of the improvements

suggested by Higher Algebra, one can hardly help making the remark

that they contrast even more strongly than the decimal notation

with the binary scale, or with the old Greek arithmetic--or than

the well-ordered subdivisions of the metrical system with the

preposterous no-systems of Great Britain, a mere fragment of which

(in the form of Table of Weights and Measures) form, perhaps the

most effective, if not the most ingenious, of the many instruments

of torture employed in our elementary teaching.--TAIT, P. G.

_Presidential Address British

Association for the Advancement of

Science (1871); Nature, Vol. 4, p. 271._

=1726.= It is true that, in the eyes of the pure mathematician,

Quaternions have one grand and fatal defect. They cannot be

applied to space of _n_ dimensions, they are contented to deal

with those poor three dimensions in which mere mortals are doomed

to dwell, but which cannot bound the limitless aspirations of a

Cayley or a Sylvester. From the physical point of view this,

instead of a defect, is to be regarded as the greatest possible

recommendation. It shows, in fact, Quaternions to be the special

instrument so constructed for application to the _Actual_ as to

have thrown overboard everything which is not absolutely

necessary, without the slightest consideration whether or no it

was thereby being rendered useless for application to the

_Inconceivable_.--TAIT, P. G.

_Presidential Address British

Association for the Advancement of

Science (1871); Nature, Vol. 4, p. 271._

=1727.= There is an old epigram which assigns the empire of the

sea to the English, of the land to the French, and of the clouds

to the Germans. Surely it was from the clouds that the Germans

fetched + and −; the ideas which these symbols have generated are

much too important to the welfare of humanity to have come from

the sea or from the land.--WHITEHEAD, A. N.

_An Introduction to Mathematics (New

York, 1911), p. 86._

=1728.= Now as to what pertains to these Surd numbers (which, as

it were by way of reproach and calumny, having no merit of their

own are also styled Irrational, Irregular, and Inexplicable) they

are by many denied to be numbers properly speaking, and are wont

to be banished from arithmetic to another Science, (which yet is

no science) viz. algebra.--BARROW, ISAAC.

_Mathematical Lectures (London, 1734),

p. 44._

=1729.= If it is true as Whewell says, that the essence of the

triumphs of science and its progress consists in that it enables

us to consider evident and necessary, views which our ancestors

held to be unintelligible and were unable to comprehend, then the

extension of the number concept to include the irrational, and we

will at once add, the imaginary, is the greatest forward step

which pure mathematics has ever taken.--HANKEL, HERMANN.

_Theorie der Complexen Zahlen (Leipzig,

1867), p. 60._

=1730.= That this subject [of imaginary magnitudes] has hitherto

been considered from the wrong point of view and surrounded by a

mysterious obscurity, is to be attributed largely to an ill-adapted

notation. If for instance, +1,−1, √−1 had been called direct,

inverse, and lateral units, instead of positive, negative, and

imaginary (or even impossible) such an obscurity would have been

out of question.--GAUSS, C. F.

_Theoria residiorum biquadraticorum,

Commentatio secunda; Werke, Bd. 2

(Goettingen, 1863), p. 177._

=1731.= ... the imaginary, this bosom-child of complex mysticism.

--DÜHRING, EUGEN.

_Kritische Geschichte der allgemeinen

Principien der Mechanik (Leipzig, 1877),

p. 517._

=1732.= Judged by the only standards which are admissible in a

pure doctrine of numbers _i_ is imaginary in the same sense as

the negative, the fraction, and the irrational, but in no other

sense; all are alike mere symbols devised for the sake of

representing the results of operations even when these results

are not numbers (positive integers).--FINE, H. B.

_The Number-System of Algebra (Boston,

1890), p. 36._

=1733.= This symbol [√-1] is restricted to a precise signification

as the representative of perpendicularity in quaternions, and this

wonderful algebra of space is intimately dependent upon the

special use of the symbol for its symmetry, elegance, and power.

The immortal author of quaternions has shown that there are other

significations which may attach to the symbol in other cases. But

the strongest use of the symbol is to be found in its magical

power of doubling the actual universe, and placing by its side an

ideal universe, its exact counterpart, with which it can be

compared and contrasted, and, by means of curiously connecting

fibres, form with it an organic whole, from which modern analysis

has developed her surpassing geometry.--PEIRCE, BENJAMIN.

_On the Uses and Transformations of

Linear Algebras; American Journal of

Mathematics, Vol. 4 (1881), p. 216._

=1734.= The conception of the inconceivable [imaginary], this

measurement of what not only does not, but cannot exist, is one

of the finest achievements of the human intellect. No one can

deny that such imaginings are indeed imaginary. But they lead to

results grander than any which flow from the imagination of the

poet. The imaginary calculus is one of the masterkeys to physical

science. These realms of the inconceivable afford in many places

our only mode of passage to the domains of positive knowledge.

Light itself lay in darkness until this imaginary calculus threw

light upon light. And in all modern researches into electricity,

magnetism, and heat, and other subtile physical inquiries, these

are the most powerful instruments.--HILL, THOMAS.

_North American Review, Vol. 85, p.

235._

=1735.= All the fruitful uses of imaginaries, in Geometry, are those

which begin and end with real quantities, and use imaginaries only

for the intermediate steps. Now in all such cases, we have a real

spatial interpretation at the beginning and end of our argument,

where alone the spatial interpretation is important; in the

intermediate links, we are dealing in purely algebraic manner with

purely algebraic quantities, and may perform any operations which

are algebraically permissible. If the quantities with which we end

are capable of spatial interpretation, then, and only then, our

results may be regarded as geometrical. To use geometrical

language, in any other case, is only a convenient help to the

imagination. To speak, for example, of projective properties which

refer to the circular points, is a mere _memoria technica_ for

purely algebraical properties; the circular points are not to be

found in space, but only in the auxiliary quantities by which

geometrical equations are transformed. That no contradictions

arise from the geometrical interpretation of imaginaries is not

wonderful; for they are interpreted solely by the rules of

Algebra, which we may admit as valid in their interpretation to

imaginaries. The perception of space being wholly absent, Algebra

rules supreme, and no inconsistency can arise.--RUSSELL, BERTRAND.

_Foundations of Geometry (Cambridge,

1897), p. 45._

=1736.= Indeed, if one understands by algebra the application of

arithmetic operations to composite magnitudes of all kinds, whether

they be rational or irrational number or space magnitudes, then

the learned Brahmins of Hindostan are the true inventors of

algebra.--HANKEL, HERMANN.

_Geschichte der Mathematik im Altertum

und Mittelalter (Leipzig, 1874), p.

195._

=1737.= It is remarkable to what extent Indian mathematics enters

into the science of our time. Both the form and the spirit of the

arithmetic and algebra of modern times are essentially Indian and

not Grecian.--CAJORI, F.

_History of Mathematics (New York,

1897), p. 100._

=1738.= There are many questions in this science [algebra] which

learned men have to this time in vain attempted to solve; and

they have stated some of these questions in their writings, to

prove that this science contains difficulties, to silence those

who pretend they find nothing in it above their ability, to warn

mathematicians against undertaking to answer every question that

may be proposed, and to excite men of genius to attempt their

solution. Of these I have selected seven.

1. To divide 10 into two parts, such, that when each part is

added to its square-root and the sums multiplied together, the

product is equal to the supposed number.

2. What square is that, which being increased or diminished by

10, the sum and remainder are both square numbers?

3. A person said he owed to Zaid 10 all but the square-root of

what he owed to Amir, and that he owed Amir 5 all but the

square-root of what he owed Zaid.

4. To divide a cube number into two cube numbers.

5. To divide 10 into two parts such, that if each is divided by

the other, and the two quotients are added together, the sum is

equal to one of the parts.

6. There are three square numbers in continued geometric

proportion, such, that the sum of the three is a square number.

7. There is a square, such, that when it is increased and

diminished by its root and 2, the sum and the difference are

squares.--KHULASAT-AL-HISAB.

_Algebra; quoted in Hutton: A

Philosophical and Mathematical

Dictionary (London, 1815), Vol. 1, p.

70._

=1739.= The solution of such questions as these [referring to the

solution of cubic equations] depends on correct judgment, aided

by the assistance of God.--BIJA GANITA.

_Quoted in Hutton: A Philosophical and

Mathematical Dictionary (London, 1815),

Vol. 1, p. 65._

=1740.= For what is the theory of determinants? It is an algebra

upon algebra; a calculus which enables us to combine and foretell

the results of algebraical operations, in the same way as algebra

itself enables us to dispense with the performance of the special

operations of arithmetic. All analysis must ultimately clothe

itself under this form.--SYLVESTER, J. J.

_Philosophical Magazine, Vol. 1, (1851),

p. 300; Collected Mathematical Papers,

Vol. 1, p. 247._

=1741.=

Fuchs. Fast möcht’ ich nun _moderne Algebra_ studieren.

Meph. Ich wünschte nicht euch irre zu führen.

Was diese Wissenschaft betrifft,

Es ist so schwer, die leere Form zu meiden,

Und wenn ihr es nicht recht begrifft,

Vermögt die Indices ihr kaum zu unterscheiden.

Am Besten ist’s, wenn ihr nur _Einem_ traut

Und auf des Meister’s Formeln baut.

Im Ganzen--haltet euch an die _Symbole_.

Dann geht ihr zu der Forschung Wohle

Ins sichre Reich der Formeln ein.

Fuchs. Ein Resultat muss beim Symbole sein?

Meph. Schon gut! Nur muss man sich nicht alzu ängstlich

quälen.

Denn eben, wo die Resultate fehlen,

Stellt ein Symbol zur rechten Zeit sich ein.

Symbolisch lässt sich alles schreiben,

Müsst nur im Allgemeinen bleiben.

Wenn man der Gleichung Lösung nicht erkannte,

Schreibt man sie als Determinante.

Schreib’ was du willst, nur rechne _nie_ was aus.

Symbole lassen trefflich sich traktieren,

Mit einem Strich ist alles auszuführen,

Und mit Symbolen kommt man immer aus.

--LASSWITZ, KURD.

_Der Faust-Tragödie (-n)ter Teil;

Zeitschrift für mathematischen und

naturwissenschaftlichen Unterricht, Bd.

14, p. 317._

Fuchs. To study _modern algebra_ I’m most persuaded.

Meph. ’Twas not my wish to lead thee astray.

But as concerns this science, truly

’Tis difficult to avoid the empty form,

And should’st thou lack clear comprehension,

Scarcely the indices thou’ll know apart.

’Tis safest far to trust but _one_

And built upon your master’s formulas.

On the whole--cling closely to your _symbols_.

Then, for the weal of research you may gain

An entrance to the formula’s sure domain.

Fuchs. The symbol, it must lead to some result?

Meph. Granted. But never worry about results,

For, mind you, just where the results are wanting

A symbol at the nick of time appears.

To symbolic treatment all things yield,

Provided we stay in the general field.

Should a solution prove elusive,

Write the equation in determinant form.

Write what you please, but _never_ calculate.

Symbols are patient and long suffering,

A single stroke completes the whole affair.

Symbols for every purpose do suffice.

=1742.= As all roads are said to lead to Rome, so I find, in my

own case at least, that all algebraic inquiries sooner or later

end at the Capitol of Modern Algebra over whose shining portal

is inscribed “Theory of Invariants.”--SYLVESTER, J. J.

_On Newton’s Rule for the Discovery of

Imaginary Roots; Collected Mathematical

Papers, Vol. 2, p. 380._

=1743.= If we consider the beauty of the theorem [Sylvester’s

Theorem on Newton’s Rule for the Discovery of Imaginary Roots]

which has now been expounded, the interest which belongs to the

rule associated with the great name of Newton, and the long lapse

of years during which the reason and extent of that rule remained

undiscovered by mathematicians, among whom Maclaurin, Waring and

Euler are explicitly included, we must regard Professor

Sylvester’s investigations made to the Theory of Equations in

modern times, justly to be ranked with those of Fourier, Sturm

and Cauchy.--TODHUNTER, I.

_Theory of Equations (London, 1904), p.

250._

=1744.= Considering the remarkable elegance, generality, and

simplicity of the method [Homer’s Method of finding the numerical

values of the roots of an equation], it is not a little

surprising that it has not taken a more prominent place in

current mathematical textbooks.... As a matter of fact, its

spirit is purely arithmetical; and its beauty, which can only be

appreciated after one has used it in particular cases, is of that

indescribably simple kind, which distinguishes the use of

position in the decimal notation and the arrangement of the

simple rules of arithmetic. It is, in short, one of those things

whose invention was the creation of a commonplace.

--CHRYSTAL, GEORGE.

_Algebra (London and Edinburgh, 1893),

Vol. 1, chap. 15, sect. 25._

=1745.= _To a missing member of a family group of terms in an

algebraical formula._

Lone and discarded one! divorced by fate,

Far from thy wished-for fellows--whither art

flown?

Where lingerest thou in thy bereaved estate,

Like some lost star, or buried meteor stone?

Thou mindst me much of that presumptuous one

Who loth, aught less than greatest, to be

great,

From Heaven’s immensity fell headlong down

To live forlorn, self-centred, desolate:

Or who, like Heraclid, hard exile bore,

Now buoyed by hope, now stretched on rack of

fear,

Till throned Astæa, wafting to his ear

Words of dim portent through the Atlantic roar,

Bade him “the sanctuary of the Muse revere

And strew with flame the dust of Isis’

shore.”

--SYLVESTER, J. J.

_Inaugural Lecture, Oxford, 1885;

Nature, Vol. 33, p. 228._

=1746.= In every subject of inquiry there are certain entities,

the mutual relations of which, under various conditions, it is

desirable to ascertain. A certain combination of these entities

are submitted to certain processes or are made the subjects of

certain operations. The theory of invariants in its widest

scientific meaning determines these combinations, elucidates

their properties, and expresses results when possible in terms of

them. Many of the general principles of political science and

economics can be represented by means of invariantive relations

connecting the factors which enter as entities into the special

problems. The great principle of chemical science which asserts

that when elementary or compound bodies combine with one another

the total weight of the materials is unchanged, is another case

in point. Again, in physics, a given mass of gas under the

operation of varying pressure and temperature has the well-known

invariant, pressure multiplied by volume and divided by absolute

temperature.... In mathematics the entities under examination may

be arithmetical, algebraical, or geometrical; the processes to

which they are subjected may be any of those which are met with

in mathematical work.... It is the _principle_ which is so

valuable. It is the _idea_ of invariance that pervades today all

branches of mathematics.--MACMAHON, P. A.

_Presidential Address British

Association for the Advancement of

Science (1901); Nature, Vol. 64, p.

481._

=1747.= [The theory of invariants] has invaded the domain of

geometry, and has almost re-created the analytical theory; but it

has done more than this for the investigations of Cayley have

required a full reconsideration of the very foundations of

geometry. It has exercised a profound influence upon the theory

of algebraic equations; it has made its way into the theory of

differential equations; and the generalisation of its ideas is

opening out new regions of most advanced and profound functional

analysis. And so far from its course being completed, its

questions fully answered, or its interest extinct, there is no

reason to suppose that a term can be assigned to its growth and

its influence.--FORSYTH, A. R.

_Presidential Address British

Association for the Advancement of

Science (1897); Nature, Vol. 56, p.

378._

=1748.= ... the doctrine of Invariants, a theory filling the heavens

like a light-bearing ether, penetrating all the branches of

geometry and analysis, revealing everywhere abiding configurations

in the midst of change, everywhere disclosing the eternal reign of

the law of form.--KEYSER, C. J.

_Lectures on Science, Philosophy and Art

(New York, 1908), p. 28._

=1749.= It is in the mathematical doctrine of Invariance, the

realm wherein are sought and found configurations and types of

being that, amidst the swirl and stress of countless hosts of

transformations remain immutable, and the spirit dwells in

contemplation of the serene and eternal reign of the subtile laws

of Form, it is there that Theology may find, if she will, the

clearest conceptions, the noblest symbols, the most inspiring

intimations, the most illuminating illustrations, and the surest

guarantees of the object of her teaching and her quest, an

Eternal Being, unchanging in the midst of the universal flux.

--KEYSER, C. J.

_Lectures on Science, Philosophy and Art

(New York, 1908), p. 42._

=1750.= I think that young chemists desirous of raising their

science to its proper rank would act wisely in making themselves

master betimes of the theory of algebraic forms. What mechanics

is to physics, that I think is algebraic morphology, founded at

option on the theory of partitions or ideal elements, or both, is

destined to be to the chemistry of the future ... invariants and

isomerism are sister theories.--SYLVESTER, J. J.

_American Journal of Mathematics, Vol. 1

(1878), p. 126._

=1751.= The great notion of Group, ... though it had barely merged

into consciousness a hundred years ago, has meanwhile become a

concept of fundamental importance and prodigious fertility, not

only affording the basis of an imposing doctrine--the Theory of

Groups--but therewith serving also as a bond of union, a kind of

connective tissue, or rather as an immense cerebro-spinal system,

uniting together a large number of widely dissimilar doctrines as

organs of a single body.--KEYSER, C. J.

_Lectures on Science, Philosophy and Art

(New York, 1908), p. 12._

=1752.= In recent times the view becomes more and more prevalent

that many branches of mathematics are nothing but the theory of

invariants of special groups.--LIE, SOPHUS.

_Continuierliche Gruppen--Scheffers

(Leipzig, 1893), p. 665._

=1753.= Universal Algebra has been looked on with some suspicion

by many mathematicians, as being without intrinsic mathematical

interest and as being comparatively useless as an engine of

investigation.... But it may be shown that Universal Algebra has

the same claim to be a serious subject of mathematical study as

any other branch of mathematics.--WHITEHEAD, A. N.

_Universal Algebra (Cambridge, 1898),

Preface, p. vi._

=1754.= [Function] theory was, in effect, founded by Cauchy; but,

outside his own investigations, it at first made slow and

hesitating progress. At the present day, its fundamental ideas

may be said almost to govern most departments of the analysis of

continuous quantity. On many of them, it has shed a completely

new light; it has educed relations between them before unknown.

It may be doubted whether any subject is at the present day so

richly endowed with variety of method and fertility of resource;

its activity is prodigious, and no less remarkable than its

activity is its freshness.--FORSYTH, A. R.

_Presidential Address British

Association for the Advancement of

Science (1897); Nature, Vol. 56, p.

378._

=1755.= Let me mention one other contribution which this theory

[Theory of functions of a complex variable] has made to knowledge

lying somewhat outside our track. During the rigorous revision to

which the foundations of the theory have been subjected in its

re-establishment by Weierstrass, new ideas as regards number and

continuity have been introduced. With him and with others

influenced by him, there has thence sprung a new theory of higher

arithmetic; and with its growth, much has concurrently been

effected in the elucidation of the general notions of number and

quantity.... It thus appears to be the fact that, as with Plato,

or Descartes, or Leibnitz, or Kant, the activity of pure

mathematics is again lending some assistance to the better

comprehension of those notions of time, space, number, quantity,

which underlie a philosophical conception of the universe.

--FORSYTH, A. R.

_Presidential Address British

Association for the Advancement of

Science (1897); Nature, Vol. 56, p.

378._

CHAPTER XVIII

GEOMETRY

=1801.= The science of figures is most glorious and beautiful.

But how inaptly it has received the name geometry!--FRISCHLINUS, N.

_Dialog 1._

=1802.= Plato said that God geometrizes continually.--PLUTARCH.

_Convivialium disputationum, liber 8,

2._

=1803.= μηδεὶς ἐγεωμέτρητος εἰσίτω μοῦ τὴν στέγην. [Let no one

ignorant of geometry enter my door.]--PLATO.

_Tzetzes, Chiliad, 8, 972._

=1804.= All the authorities agree that he [Plato] made a study of

geometry or some exact science an indispensable preliminary to

that of philosophy. The inscription over the entrance to his

school ran “Let none ignorant of geometry enter my door,” and on

one occasion an applicant who knew no geometry is said to have

been refused admission as a student.--BALL, W. W. R.

_History of Mathematics (London, 1901),

p. 45._

=1805.= Form and size constitute the foundation of all search for

truth.--PARKER, F. W.

_Talks on Pedagogics (New York, 1894),

p. 72._

=1806.= At present the science [of geometry] is in flat

contradiction to the language which geometricians use, as will

hardly be denied by those who have any acquaintance with the

study: for they speak of finding the side of a square, and

applying and adding, and so on, as if they were engaged in some

business, and as if all their propositions had a practical end in

view: whereas in reality the science is pursued wholly for the

sake of knowledge.

Certainly, he said.

Then must not a further admission be made?

What admission?

The admission that this knowledge at which geometry aims is of

the eternal, and not of the perishing and transient.

That may be easily allowed. Geometry, no doubt, is the knowledge

of what eternally exists.

Then, my noble friend, geometry will draw the soul towards truth,

and create the mind of philosophy, and raise up that which is now

unhappily allowed to fall down.--PLATO.

_Republic [Jowett-Davies], Bk. 7, p.

527._

=1807.= Among them [the Greeks] geometry was held in highest

honor: nothing was more glorious than mathematics. But we have

limited the usefulness of this art to measuring and calculating.

--CICERO.

_Tusculanae Disputationes, 1, 2, 5._

=1808.=

Geometria,

Through which a man hath the sleight

Of length, and brede, of depth, of height.

--GOWER, JOHN.

_Confessio Amantis, Bk. 7._

=1809.= Geometrical truths are in a way asymptotes to physical truths,

that is to say, the latter approach the former indefinitely near

without ever reaching them exactly.--D’ALEMBERT.

_Quoted in Rebière: Mathématiques et

Mathématiciens (Paris, 1898), p. 10._

=1810.= Geometry exhibits the most perfect example of logical

stratagem.--BUCKLE, H. T.

_History of Civilization in England (New

York, 1891), Vol. 2, p. 342._

=1811.= It is the glory of geometry that from so few principles,

fetched from without, it is able to accomplish so much.--NEWTON.

_Philosophiae Naturalis Principia

Mathematica, Praefat._

=1812.= Geometry is the application of strict logic to those

properties of space and figure which are self-evident, and which

therefore cannot be disputed. But the rigor of this science is

carried one step further; for no property, however evident it may

be, is allowed to pass without demonstration, if that can be

given. The question is therefore to demonstrate all geometrical

truths with the smallest possible number of assumptions.

--DE MORGAN, A.

_On the Study and Difficulties of

Mathematics (Chicago, 1902), p. 231._

=1813.= Geometry is a true natural science:--only more simple,

and therefore more perfect than any other. We must not suppose

that, because it admits the application of mathematical analysis,

it is therefore a purely logical science, independent of

observation. Every body studied by geometers presents some

primitive phenomena which, not being discoverable by reasoning,

must be due to observation alone.--COMTE, A.

_Positive Philosophy [Martineau], Bk. 1,

chap. 3._

=1814.= Geometry in every proposition speaks a language which

experience never dares to utter; and indeed of which she but half

comprehends the meaning. Experience sees that the assertions are

true, but she sees not how profound and absolute is their truth.

She unhesitatingly assents to the laws which geometry delivers,

but she does not pretend to see the origin of their obligation.

She is always ready to acknowledge the sway of pure scientific

principles as a matter of fact, but she does not dream of

offering her opinion on their authority as a matter of right;

still less can she justly claim to herself the source of that

authority.--WHEWELL, WILLIAM.

_The Philosophy of the Inductive

Sciences, Part 1, Bk. 1, chap. 6, sect.

1 (London, 1858)._

=1815.= Geometry is the science created to give understanding

and mastery of the external relations of things; to make easy

the explanation and description of such relations and the

transmission of this mastery.--HALSTED, G. B.

_Proceedings of the American Association

for the Advancement of Science (1904),

p. 359._

=1816.= A mathematical point is the most indivisible and unique

thing which art can present.--DONNE, JOHN.

_Letters, 21._

=1817.= It is certain that from its completeness, uniformity and

faultlessness, from its arrangement and progressive character,

and from the universal adoption of the completest and best line

of argument, Euclid’s “Elements” stand pre-eminently at the head

of all human productions. In no science, in no department of

knowledge, has anything appeared like this work: for upward of

2000 years it has commanded the admiration of mankind, and that

period has suggested little toward its improvement.--KELLAND, P.

_Lectures on the Principles of

Demonstrative Mathematics (London,

1843), p. 17._

=1818.= In comparing the performance in Euclid with that in

Arithmetic and Algebra there could be no doubt that Euclid had

made the deepest and most beneficial impression: in fact it might

be asserted that this constituted by far the most valuable part

of the whole training to which such persons [students, the

majority of which were not distinguished for mathematical taste

and power] were subjected.--TODHUNTER, I.

_Essay on Elementary Geometry; Conflict

of Studies and other Essays (London,

1873), p. 167._

=1819.= In England the geometry studied is that of Euclid, and I

hope it never will be any other; for this reason, that so much

has been written on Euclid, and all the difficulties of geometry

have so uniformly been considered with reference to the form in

which they appear in Euclid, that the study of that author is a

better key to a great quantity of useful reading than any other.

--DE MORGAN, A.

_Elements of Algebra (London, 1837),

Introduction._

=1820.= This book [Euclid] has been for nearly twenty-two

centuries the encouragement and guide of that scientific thought

which is one thing with the progress of man from a worse to a

better state. The encouragement; for it contained a body of

knowledge that was really known and could be relied on, and that

moreover was growing in extent and application. For even at the

time this book was written--shortly after the foundation of the

Alexandrian Museum--Mathematics was no longer the merely ideal

science of the Platonic school, but had started on her career of

conquest over the whole world of Phenomena. The guide; for the

aim of every scientific student of every subject was to bring his

knowledge of that subject into a form as perfect as that which

geometry had attained. Far up on the great mountain of Truth,

which all the sciences hope to scale, the foremost of that sacred

sisterhood was seen, beckoning for the rest to follow her. And

hence she was called, in the dialect of the Phythagoreans, “the

purifier of the reasonable soul.”--CLIFFORD, W. K.

_Lectures and Essays (London, 1901),

Vol. 1, p. 354._

=1821.= [Euclid] at once the inspiration and aspiration of

scientific thought.--CLIFFORD, W. K.

_Lectures and Essays (London, 1901), Vol

1, p. 355._

=1822.= The “elements” of the Great Alexandrian remain for all

time the first, and one may venture to assert, the _only_ perfect

model of logical exactness of principles, and of rigorous

development of theorems. If one would see how a science can be

constructed and developed to its minutest details from a very

small number of intuitively perceived axioms, postulates, and

plain definitions, by means of rigorous, one would almost say

chaste, syllogism, which nowhere makes use of surreptitious or

foreign aids, if one would see how a science may thus be

constructed one must turn to the elements of Euclid.--HANKEL, H.

_Die Entwickelung der Mathematik in den

letzten Jahrhunderten (Tübingen, 1884),

p. 7._

=1823.= If we consider him [Euclid] as meaning to be what

his commentators have taken him to be, a model of the most

unscrupulous formal rigour, we can deny that he has altogether

succeeded, though we admit that he made the nearest approach.

--DE MORGAN, A.

_Smith’s Dictionary of Greek and Roman

Biography and Mythology (London, 1902);

Article “Eucleides.”_

=1824.= The Elements of Euclid is as small a part of mathematics

as the Iliad is of literature; or as the sculpture of Phidias is

of the world’s total art.--KEYSER, C. J.

_Lectures on Science, Philosophy and Art

(New York, 1908), p. 8._

=1825.= I should rejoice to see ... Euclid honourably shelved

or buried “deeper than did ever plummet sound” out of the

schoolboys’ reach; morphology introduced into the elements of

algebra; projection, correlation, and motion accepted as aids to

geometry; the mind of the student quickened and elevated and his

faith awakened by early initiation into the ruling ideas of

polarity, continuity, infinity, and familiarization with the

doctrines of the imaginary and inconceivable.--SYLVESTER, J. J.

_A Plea for the Mathematician; Nature,

Vol. 1, p. 261._

=1826.= The early study of Euclid made me a hater of geometry,

... and yet, in spite of this repugnance, which had become a

second nature in me, whenever I went far enough into any

mathematical question, I found I touched, at last, a geometrical

bottom.--SYLVESTER, J. J.

_A Plea for the Mathematician; Nature,

Vol. 1, p. 262._

=1827.= Newton had so remarkable a talent for mathematics that

Euclid’s Geometry seemed to him “a trifling book,” and he wondered

that any man should have taken the trouble to demonstrate

propositions, the truth of which was so obvious to him at the

first glance. But, on attempting to read the more abstruse

geometry of Descartes, without having mastered the elements of the

science, he was baffled, and was glad to come back again to his

Euclid.--PARTON, JAMES.

_Sir Isaac Newton._

=1828.= As to the need of improvement there can be no question

whilst the reign of Euclid continues. My own idea of a useful

course is to begin with arithmetic, and then not Euclid but

algebra. Next, not Euclid, but practical geometry, solid as well

as plane; not demonstration, but to make acquaintance. Then not

Euclid, but elementary vectors, conjoined with algebra, and

applied to geometry. Addition first; then the scalar product.

Elementary calculus should go on simultaneously, and come into

the vector algebraic geometry after a bit. Euclid might be an

extra course for learned men, like Homer. But Euclid for children

is barbarous.--HEAVISIDE, OLIVER.

_Electro-Magnetic Theory (London, 1893),

Vol. 1, p. 148._

=1829.= Geometry is nothing if it be not rigorous, and the whole

educational value of the study is lost, if strictness of

demonstration be trifled with. The methods of Euclid are, by

almost universal consent, unexceptionable in point of rigour.

--SMITH, H. J. S.

_Nature, Vol. 8, p. 450._

=1830.= To seek for proof of geometrical propositions by an

appeal to observation proves nothing in reality, except that the

person who has recourse to such grounds has no due apprehension

of the nature of geometrical demonstration. We have heard of

persons who convince themselves by measurement that the

geometrical rule respecting the squares on the sides of a

right-angles triangle was true: but these were persons whose

minds had been engrossed by practical habits, and in whom

speculative development of the idea of space had been stifled by

other employments.--WHEWELL, WILLIAM.

_The Philosophy of the Inductive

Sciences, (London, 1858), Part 1, Bk. 2,

chap. 1, sect. 4._

=1831.= No one has ever given so easy and natural a chain of

geometrical consequences [as Euclid]. There is a never-erring

truth in the results.--DE MORGAN, A.

_Smith’s Dictionary of Greek and Roman

Biography and Mythology (London, 1902);

Article “Eucleides.”_

=1832.= Beyond question, Egyptian geometry, such as it was, was

eagerly studied by the early Greek philosophers, and was the germ

from which in their hands grew that magnificent science to which

every Englishman is indebted for his first lessons in right

seeing and thinking.--GOW, JAMES.

_A Short History of Greek Mathematics

(Cambridge, 1884), p. 131._

=1833.=

A figure and a step onward:

Not a figure and a florin.

--MOTTO OF THE PYTHAGOREAN BROTHERHOOD.

_W. B. Frankland: Story of Euclid

(London, 1902), p. 33._

=1834.= The doctrine of proportion, as laid down in the fifth

book of Euclid, is, probably, still unsurpassed as a masterpiece

of exact reasoning; although the cumbrousness of the forms of

expression which were adopted in the old geometry has led to the

total exclusion of this part of the elements from the ordinary

course of geometrical education. A zealous defender of Euclid

might add with truth that the gap thus created in the elementary

teaching of mathematics has never been adequately supplied.

--SMITH, H. J. S.

_Presidential Address British

Association for the Advancement of

Science (1873); Nature, Vol. 8, p. 451._

=1835.= The Definition in the Elements, according to Clavius, is

this: Magnitudes are said to be in the same Reason [ratio], a

first to a second, and a third to a fourth, when the Equimultiples

of the first and third according to any Multiplication whatsoever

are both together either short of, equal to, or exceed the

Equimultiples of the second and fourth, if those be taken,

which answer one another.... Such is Euclid’s Definition of

Proportions; that _scare_-Crow at which the over modest or

slothful Dispositions of Men are generally affrighted: they are

modest, who distrust their own Ability, as soon as a Difficulty

appears, but they are slothful that will not give some Attention

for the learning of Sciences; as if while we are involved in

Obscurity we could clear ourselves without Labour. Both of which

Sorts of Persons are to be admonished, that the former be not

discouraged, nor the latter refuse a little Care and Diligence

when a Thing requires some Study.--BARROW, ISAAC.

_Mathematical Lectures (London, 1734),

p. 388._

=1836.= Of all branches of human knowledge, there is none which,

like it [geometry] has sprung a completely armed Minerva from the

head of Jupiter; none before whose death-dealing Aegis doubt

and inconsistency have so little dared to raise their eyes.

It escapes the tedious and troublesome task of collecting

experimental facts, which is the province of the natural sciences

in the strict sense of the word: the sole form of its scientific

method is deduction. Conclusion is deduced from conclusion, and

yet no one of common sense doubts but that these geometrical

principles must find their practical application in the real

world about us. Land surveying, as well as architecture, the

construction of machinery no less than mathematical physics, are

continually calculating relations of space of the most varied

kinds by geometrical principles; they expect that the success of

their constructions and experiments shall agree with their

calculations; and no case is known in which this expectation has

been falsified, provided the calculations were made correctly and

with sufficient data.--HELMHOLTZ, H.

_The Origin and Significance of

Geometrical Axioms; Popular Scientific

Lectures [Atkinson], Second Series (New

York, 1881), p. 27._

=1837.= The amazing triumphs of this branch of mathematics

[geometry] show how powerful a weapon that form of deduction is

which proceeds by an artificial reparation of facts, in

themselves inseparable.--BUCKLE, H. T.

_History of Civilization in England (New

York, 1891), Vol. 2, p. 343._

=1838.= Every theorem in geometry is a law of external nature,

and might have been ascertained by generalizing from observation

and experiment, which in this case resolve themselves into

comparisons and measurements. But it was found practicable, and

being practicable was desirable, to deduce these truths by

ratiocination from a small number of general laws of nature, the

certainty and universality of which was obvious to the most

careless observer, and which compose the first principles and

ultimate premises of the science.--MILL, J. S.

_System of Logic, Bk. 3, chap. 24, sect.

7._

=1839.= All such reasonings [natural philosophy, chemistry,

agriculture, political economy, etc.] are, in comparison with

mathematics, very complex; requiring so much _more_ than that

does, beyond the process of merely deducing the conclusion

logically from the premises: so that it is no wonder that the

longest mathematical demonstration should be much more easily

constructed and understood, than a much shorter train of just

reasoning concerning real facts. The former has been aptly

compared to a long and steep, but even and regular, flight of

steps, which tries the breath, and the strength, and the

perseverance only; while the latter resembles a short, but rugged

and uneven, ascent up a precipice, which requires a quick eye,

agile limbs, and a firm step; and in which we have to tread now

on this side, now on that--ever considering as we proceed,

whether this or that projection will afford room for our foot, or

whether some loose stone may not slide from under us. There are

probably as many steps of pure reasoning in one of the longer of

Euclid’s demonstrations, as in the whole of an argumentative

treatise on some other subject, occupying perhaps a considerable

volume.--WHATELY, R.

_Elements of Logic, Bk. 4, chap. 2,

sect. 5._

=1840.=

[Geometry] that held acquaintance with the stars,

And wedded soul to soul in purest bond

Of reason, undisturbed by space or time.

--WORDSWORTH.

_The Prelude, Bk. 5._

=1841.= The statement that a given individual has received a

sound geometrical training implies that he has segregated from

the whole of his sense impressions a certain set of these

impressions, that he has eliminated from their consideration all

irrelevant impressions (in other words, acquired a subjective

command of these impressions), that he has developed on the basis

of these impressions an ordered and continuous system of logical

deduction, and finally that he is capable of expressing the

nature of these impressions and his deductions therefrom in terms

simple and free from ambiguity. Now the slightest consideration

will convince any one not already conversant with the idea, that

the same sequence of mental processes underlies the whole career

of any individual in any walk of life if only he is not concerned

entirely with manual labor; consequently a full training in the

performance of such sequences must be regarded as forming an

essential part of any education worthy of the name. Moreover the

full appreciation of such processes has a higher value than is

contained in the mental training involved, great though this be,

for it induces an appreciation of intellectual unity and beauty

which plays for the mind that part which the appreciation of

schemes of shape and color plays for the artistic faculties; or,

again, that part which the appreciation of a body of religious

doctrine plays for the ethical aspirations. Now geometry is not

the sole possible basis for inculcating this appreciation. Logic

is an alternative for adults, provided that the individual is

possessed of sufficient wide, though rough, experience on which

to base his reasoning. Geometry is, however, highly desirable in

that the objective bases are so simple and precise that they can

be grasped at an early age, that the amount of training for the

imagination is very large, that the deductive processes are not

beyond the scope of ordinary boys, and finally that it affords a

better basis for exercise in the art of simple and exact

expression than any other possible subject of a school course.

--CARSON, G. W. L.

_The Functions of Geometry as a Subject

of Education (Tonbridge, 1910), p. 3._

=1842.= It seems to me that the thing that is wanting in the

education of women is not the acquaintance with any facts, but

accurate and scientific habits of thought, and the courage to

think that true which appears unlikely. And for supplying this

want there is a special advantage in geometry, namely that it

does not require study of a physically laborious kind, but rather

that rapid intuition which women certainly possess; so that it is

fit to become a scientific pursuit for them.--CLIFFORD, W. K.

_Quoted by Pollock in Clifford’s

Lectures and Essays (London, 1901), Vol.

1, Introduction, p. 43._

=1843.=

On the lecture slate

The circle rounded under female hands

With flawless demonstration.

--TENNYSON.

_The Princess, II, l. 493._

=1844.= It is plain that that part of geometry which bears upon

strategy does concern us. For in pitching camps, or in occupying

positions, or in closing or extending the lines of an army, and

in all the other manœuvres of an army whether in battle or on

the march, it will make a great difference to a general, whether

he is a geometrician or not.--PLATO.

_Republic, Bk. 7, p. 526._

=1845.= Then nothing should be more effectually enacted, than

that the inhabitants of your fair city should learn geometry.

Moreover the science has indirect effects, which are not small.

Of what kind are they? he said.

There are the military advantages of which you spoke, I said; and

in all departments of study, as experience proves, any one who

has studied geometry is infinitely quicker of apprehension.--PLATO.

_Republic [Jowett], Bk. 7, p. 527._

=1846.= It is doubtful if we have any other subject that does so

much to bring to the front the danger of carelessness, of

slovenly reasoning, of inaccuracy, and of forgetfulness as this

science of geometry, which has been so polished and perfected as

the centuries have gone on.--SMITH, D. E.

_The Teaching of Geometry (Boston,

1911), p. 12._

=1847.= The culture of the geometric imagination, tending to

produce precision in remembrance and invention of visible forms

will, therefore, tend directly to increase the appreciation of

works of belles-letters.--HILL, THOMAS.

_The Uses of Mathesis; Bibliotheca

Sacra, Vol. 32, p. 504._

=1848.=

Yet may we not entirely overlook

The pleasures gathered from the rudiments

Of geometric science. Though advanced

In these inquiries, with regret I speak,

No farther than the threshold, there I found

Both elevation and composed delight:

With Indian awe and wonder, ignorance pleased

With its own struggles, did I meditate

On the relations those abstractions bear

To Nature’s laws.

* * * * *

More frequently from the same source I drew

A pleasure quiet and profound, a sense

Of permanent and universal sway,

And paramount belief; there, recognized

A type, for finite natures, of the one

Supreme Existence, the surpassing life

Which to the boundaries of space and time,

Of melancholy space and doleful time,

Superior and incapable of change,

Nor touched by welterings of passion--is,

And hath the name of God. Transcendent peace

And silence did wait upon these thoughts

That were a frequent comfort to my youth.

* * * * *

Mighty is the charm

Of those abstractions to a mind beset

With images and haunted by himself,

And specially delightful unto me

Was that clear synthesis built up aloft

So gracefully; even then when it appeared

Not more than a mere plaything, or a toy

To sense embodied: not the thing it is

In verity, an independent world,

Created out of pure intelligence.

--WORDSWORTH.

_The Prelude, Bk. 6._

=1849.=

’Tis told by one whom stormy waters threw,

With fellow-sufferers by the shipwreck spared,

Upon a desert coast, that having brought

To land a single volume, saved by chance,

A treatise of Geometry, he wont,

Although of food and clothing destitute,

And beyond common wretchedness depressed,

To part from company, and take this book

(Then first a self taught pupil in its truths)

To spots remote, and draw his diagrams

With a long staff upon the sand, and thus

Did oft beguile his sorrow, and almost

Forget his feeling:

--WORDSWORTH.

_The Prelude, Bk. 6._

=1850.= We study art because we receive pleasure from the great

works of the masters, and probably we appreciate them the more

because we have dabbled a little in pigments or in clay. We do

not expect to be composers, or poets, or sculptors, but we wish

to appreciate music and letters and the fine arts, and to derive

pleasure from them and be uplifted by them....

So it is with geometry. We study it because we derive pleasure

from contact with a great and ancient body of learning that has

occupied the attention of master minds during the thousands of

years in which it has been perfected, and we are uplifted by it.

To deny that our pupils derive this pleasure from the study is to

confess ourselves poor teachers, for most pupils do have positive

enjoyment in the pursuit of geometry, in spite of the tradition

that leads them to proclaim a general dislike for all study. This

enjoyment is partly that of the game,--the playing of a game that

can always be won, but that cannot be won too easily. It is

partly that of the aesthetic, the pleasure of symmetry of form,

the delight of fitting things together. But probably it lies

chiefly in the mental uplift that geometry brings, the contact

with absolute truth, and the approach that one makes to the

Infinite. We are not quite sure of any one thing in biology; our

knowledge of geology is relatively very slight, and the economic

laws of society are uncertain to every one except some individual

who attempts to set them forth; but before the world was

fashioned the square on the hypotenuse was equal to the sum of

the squares on the other two sides of a right triangle, and it

will be so after this world is dead; and the inhabitant of Mars,

if he exists, probably knows its truth as we know it. The uplift

of this contact with absolute truth, with truth eternal, gives

pleasure to humanity to a greater or less degree, depending upon

the mental equipment of the particular individual; but it

probably gives an appreciable amount of pleasure to every student

of geometry who has a teacher worthy of the name.--SMITH, D. E.

_The Teaching of Geometry (Boston,

1911), p. 16._

=1851.= No other person can judge better of either [the merits of

a writer and the merits of his works] than himself; for none have

had access to a closer or more deliberate examination of them. It

is for this reason, that in proportion that the value of a work

is intrinsic, and independent of opinion, the less eagerness will

the author feel to conciliate the suffrages of the public. Hence

that inward satisfaction, so pure and so complete, which the

study of geometry yields. The progress which an individual makes

in this science, the degree of eminence which he attains in it,

all this may be measured with the same rigorous accuracy as the

methods about which his thoughts are employed. It is only when we

entertain some doubts about the justness of our own standard,

that we become anxious to relieve ourselves from our uncertainty,

by comparing it with the standard of another. Now, in all matters

which fall under the cognizance of taste, this standard is

necessarily somewhat variable; depending on a sort of gross

estimate, always a little arbitrary, either in whole or in part;

and liable to continual alteration in its dimensions, from

negligence, temper, or caprice. In consequence of these

circumstances I have no doubt, that if men lived separate from

each other, and could in such a situation occupy themselves about

anything but self-preservation, they would prefer the study of

the exact sciences to the cultivation of the agreeable arts. It

is chiefly on account of others, that a man aims at excellence in

the latter, it is on his own account that he devotes himself to

the former. In a desert island, accordingly, I should think that

a poet could scarcely be vain; whereas a geometrician might still

enjoy the pride of discovery.--D’ALEMBERT.

_Essai sur les Gens Lettres; Melages

(Amsterdam 1764), t. 1, p. 334._

=1852.= If it were required to determine inclined planes of

varying inclinations of such lengths that a free rolling body

would descend on them in equal times, any one who understands the

mechanical laws involved would admit that this would necessitate

sundry preparations. But in the circle the proper arrangement

takes place of its own accord for an infinite variety of

positions yet with the greatest accuracy in each individual case.

For all chords which meet the vertical diameter whether at its

highest or lowest point, and whatever their inclinations, have

this in common: that the free descent along them takes place in

equal times. I remember, one bright pupil, who, after I had

stated and demonstrated this theorem to him, and he had caught

the full import of it, was moved as by a miracle. And, indeed,

there is just cause for astonishment and wonder when one beholds

such a strange union of manifold things in accordance with such

fruitful rules in so plain and simple an object as the circle.

Moreover, there is no miracle in nature, which because of its

pervading beauty or order, gives greater cause for astonishment,

unless it be, for the reason that its causes are not so clearly

comprehended, marvel being a daughter of ignorance.--KANT.

_Der einzig mögliche Beweisgrund zu

einer Demonstration des Daseins Gottes;

Werke (Hartenstein), Bd. 2, p. 137._

=1853.= These examples [taken from the geometry of the circle]

indicate what a countless number of other such harmonic relations

obtain in the properties of space, many of which are manifested

in the relations of the various classes of curves in higher

geometry, all of which, besides exercising the understanding

through intellectual insight, affect the emotion in a similar or

even greater degree than the occasional beauties of nature.--KANT.

_Der einzig mögliche Beweisgrund zu

einer Demonstration des Daseins Gottes;

Werke (Hartenstein), Bd. 2, p. 138._

=1854.= But neither thirty years, nor thirty centuries, affect

the clearness, or the charm, of Geometrical truths. Such a

theorem as “the square of the hypotenuse of a right-angled

triangle is equal to the sum of the squares of the sides” is as

dazzlingly beautiful now as it was in the day when Pythagoras

first discovered it, and celebrated its advent, it is said, by

sacrificing a hecatomb of oxen--a method of doing honor to

Science that has always seemed to me _slightly_ exaggerated and

uncalled-for. One can imagine oneself, even in these degenerate

days, marking the epoch of some brilliant scientific discovery by

inviting a convivial friend or two, to join one in a beefsteak

and a bottle of wine. But a _hecatomb_ of oxen! It would produce

a quite inconvenient supply of beef.--DODGSON, C. L.

_A New Theory of Parallels (London,

1895), Introduction, p. 16._

=1855.= After Pythagoras discovered his fundamental theorem he

sacrificed a hecatomb of oxen. Since that time all dunces[10]

[Ochsen] tremble whenever a new truth is discovered.--BOERNE.

_Quoted in Moszkowski: Die unsterbliche

Kiste (Berlin, 1908), p. 18._

[10] In the German vernacular a dunce or blockhead

is called an ox.

=1856.=

_Vom Pythagorieschen Lehrsatz._

Die Wahrheit, sie besteht in Ewigkeit,

Wenn erst die blöde Welt ihr Licht erkannt:

Der Lehrsatz, nach Pythagoras benannt,

Gilt heute, wie er galt in seiner Zeit.

Ein Opfer hat Pythagoras geweiht

Den Göttern, die den Lichtstrahl ihm gesandt;

Es thaten kund, geschlachtet und verbrannt,

Ein hundert Ochsen seine Dankbarkeit.

Die Ochsen seit den Tage, wenn sie wittern,

Dass eine neue Wahrheit sich enthülle,

Erheben ein unmenschliches Gebrülle;

Pythagoras erfüllt sie mit Entsetzen;

Und machtlos, sich dem Licht zu wiedersetzen,

Verschiessen sie die Augen und erzittern.

--CHAMISSO, ADELBERT VON.

_Gedichte, 1835 (Haushenbusch), (Berlin,

1889), p. 302._

Truth lasts throughout eternity,

When once the stupid world its light discerns:

The theorem, coupled with Pythagoras’ name,

Holds true today, as’t did in olden times.

A splendid sacrifice Pythagoras brought

The gods, who blessed him with this ray divine;

A great burnt offering of a hundred kine,

Proclaimed afar the sage’s gratitude.

Now since that day, all cattle [blockheads] when they

scent

New truth about to see the light of day,

In frightful bellowings manifest their dismay;

Pythagoras fills them all with terror;

And powerless to shut out light by error,

In sheer despair they shut their eyes and tremble.

=1857.= To the question “Which is the signally most beautiful of

geometrical truths?” Frankland replies: “One star excels another

in brightness, but the very sun will be, by common consent, a

property of the circle [Euclid, Book 3, Proposition 31] selected

for particular mention by Dante, that greatest of all exponents

of the beautiful.”--FRANKLAND, W. B.

_The Story of Euclid (London, 1902), p.

70._

=1858.=

As one

Who vers’d in geometric lore, would fain

Measure the circle; and, though pondering long

And deeply, that beginning, which he needs,

Finds not; e’en such was I, intent to scan

The novel wonder, and trace out the form,

How to the circle fitted, and therein

How plac’d: but the flight was not for my wing;

--DANTE.

_Paradise [Carey] Canto 33, lines

122-129._

=1859.= If geometry were as much opposed to our passions and

present interests as is ethics, we should contest it and violate

it but little less, notwithstanding all the demonstrations of

Euclid and of Archimedes, which you would call dreams and believe

full of paralogisms; and Joseph Scaliger, Hobbes, and others, who

have written against Euclid and Archimedes, would not find

themselves in such a small company as at present.--LEIBNITZ.

_New Essays concerning Human

Understanding [Langley], Bk. 1, chap. 2,

sect. 12._

=1860.= I have no fault to find with those who teach geometry.

That science is the only one which has not produced sects; it is

founded on analysis and on synthesis and on the calculus; it does

not occupy itself with probable truth; moreover it has the same

method in every country.--FREDERICK THE GREAT.

_Oeuvres (Decker), t. 7, p. 100._

=1861.= There are, undoubtedly, the most ample reasons for

stating both the principles and theorems [of geometry] in their

general form, .... But, that an unpractised learner, even in

making use of one theorem to demonstrate another, reasons rather

from particular to particular than from the general proposition,

is manifest from the difficulty he finds in applying a theorem to

a case in which the configuration of the diagram is extremely

unlike that of the diagram by which the original theorem was

demonstrated. A difficulty which, except in cases of unusual

mental powers, long practice can alone remove, and removes

chiefly by rendering us familiar with all the configurations

consistent with the general conditions of the theorem.--MILL, J. S.

_System of Logic, Bk. 2, chap. 3, sect.

3._

=1862.= The reason why I impute any defect to geometry, is,

because its original and fundamental principles are deriv’d

merely from appearances; and it may perhaps be imagin’d, that

this defect must always attend it, and keep it from ever reaching

a greater exactness in the comparison of objects or ideas, than

what our eye or imagination alone is able to attain. I own that

this defect so far attends it, as to keep it from ever aspiring

to a full certainty. But since these fundamental principles

depend on the easiest and least deceitful appearances, they

bestow on their consequences a degree of exactness, of which

these consequences are singly incapable.--HUME, D.

_A Treatise of Human Nature, Part 3,

sect. 1._

=1863.= I have already observed, that geometry, or the art, by

which we fix the proportions of figures, tho’ it much excels both

in universality and exactness, the loose judgments of the senses

and imagination; yet never attains a perfect precision and

exactness. Its first principles are still drawn from the general

appearance of the objects; and that appearance can never afford

us any security, when we examine the prodigious minuteness of

which nature is susceptible....

There remain, therefore, algebra and arithmetic as the only

sciences, in which we can carry on a chain of reasoning to any

degree of intricacy, and yet preserve a perfect exactness and

certainty.--HUME, D.

_A Treatise of Human Nature, Part 3,

sect. 1._

=1864.= All geometrical reasoning is, in the last resort,

circular: if we start by assuming points, they can only be

defined by the lines or planes which relate them; and if we start

by assuming lines or planes, they can only be defined by the

points through which they pass.--RUSSELL, BERTRAND.

_Foundations of Geometry (Cambridge,

1897), p. 120._

=1865.= The description of right lines and circles, upon which

Geometry is founded, belongs to Mechanics. Geometry does not

teach us to draw these lines, but requires them to be drawn....

it requires that the learner should first be taught to describe

these accurately, before he enters upon Geometry; then it shows

how by these operations problems may be solved. To describe right

lines and circles are problems, but not geometrical problems. The

solution of these problems is required from Mechanics; by

Geometry the use of them, when solved, is shown.... Therefore

Geometry is founded in mechanical practice, and is nothing but

that part of universal Mechanics which accurately proposes and

demonstrates the art of measuring. But since the manual arts are

chiefly conversant in the moving of bodies, it comes to pass

that Geometry is commonly referred to their magnitudes, and

Mechanics to their motion.--NEWTON.

_Philosophiae Naturalis Principia

Mathematica, Praefat._

=1866.= We must, then, admit ... that there is an independent

science of geometry just as there is an independent science of

physics, and that either of these may be treated by mathematical

methods. Thus geometry becomes the simplest of the natural

sciences, and its axioms are of the nature of physical laws, to

be tested by experience and to be regarded as true only within

the limits of error of observation--BÔCHER, MAXIME.

_Bulletin American Mathematical Society,

Vol. 2 (1904), p. 124._

=1867.= Geometry is not an experimental science; experience forms

merely the occasion for our reflecting upon the geometrical ideas

which pre-exist in us. But the occasion is necessary, if it did

not exist we should not reflect, and if our experiences were

different, doubtless our reflections would also be different.

Space is not a form of sensibility; it is an instrument which

serves us not to represent things to ourselves, but to reason

upon things.--POINCARÉ, H.

_On the Foundations of Geometry; Monist,

Vol. 9 (1898-1899), p. 41._

=1868.= It has been said that geometry is an instrument. The

comparison may be admitted, provided it is granted at the same

time that this instrument, like Proteus in the fable, ought

constantly to change its form.--ARAGO.

_Oeuvres, t. 2 (1854), p. 694._

=1869.= It is essential that the treatment [of geometry] should

be rid of everything superfluous, for the superfluous is an

obstacle to the acquisition of knowledge; it should select

everything that embraces the subject and brings it to a focus,

for this is of the highest service to science; it must have great

regard both to clearness and to conciseness, for their opposites

trouble our understanding; it must aim to generalize its

theorems, for the division of knowledge into small elements

renders it difficult of comprehension.--PROCLUS.

_Quoted in D. E. Smith: The Teaching of

Geometry (Boston, 1911), p. 71._

=1870.= Many are acquainted with mathematics, but mathesis few

know. For it is one thing to know a number of propositions and to

make some obvious deductions from them, by accident rather than

by any sure method of procedure, another thing to know clearly

the nature and character of the science itself, to penetrate into

its inmost recesses, and to be instructed by its universal

principles, by which facility in working out countless problems

and their proofs is secured. For as the majority of artists, by

copying the same model again and again, gain certain technical

skill in painting, but no other knowledge of the art of painting

than what their eyes suggest, so many, having read the books of

Euclid and other geometricians, are wont to devise, in imitation

of them and to prove some propositions, but the most profound

method of solving more difficult demonstrations and problems they

are utterly ignorant of.--LAFAILLE, J. C.

_Theoremata de Centro Gravitatis

(Anvers, 1632), Praefat._

=1871.= The elements of plane geometry should precede algebra for

every reason known to sound educational theory. It is more

fundamental, more concrete, and it deals with things and their

relations rather than with symbols.--BUTLER, N. M.

_The Meaning of Education etc. (New

York, 1905), p. 171._

=1872.= The reason why geometry is not so difficult as algebra,

is to be found in the less general nature of the symbols

employed. In algebra a general proposition respecting numbers is

to be proved. Letters are taken which may represent any of the

numbers in question, and the course of the demonstration, far

from making use of a particular case, does not even allow that

any reasoning, however general in its nature, is conclusive,

unless the symbols are as general as the arguments.... In

geometry on the contrary, at least in the elementary parts, any

proposition may be safely demonstrated on reasonings on any one

particular example.... It also affords some facility that the

results of elementary geometry are in many cases sufficiently

evident of themselves to the eye; for instance, that two sides of

a triangle are greater than the third, whereas in algebra many

rudimentary propositions derive no evidence from the senses; for

example, that a³−b³ is always divisible without a remainder by

a−b.--DE MORGAN, A.

_On the Study and Difficulties of

Mathematics (Chicago, 1902), chap. 13._

=1873.= The principal characteristics of the ancient geometry

are:--

(1) A wonderful clearness and definiteness of its concepts and an

almost perfect logical rigour of its conclusions.

(2) A complete want of general principles and methods.... In the

demonstration of a theorem, there were, for the ancient

geometers, as many different cases requiring separate proof as

there were different positions of the lines. The greatest

geometers considered it necessary to treat all possible cases

independently of each other, and to prove each with equal

fulness. To devise methods by which all the various cases could

all be disposed of with one stroke, was beyond the power of the

ancients.--CAJORI, F.

_History of Mathematics (New York,

1897), p. 62._

=1874.= It has been observed that the ancient geometers made use

of a kind of analysis, which they employed in the solution of

problems, although they begrudged to posterity the knowledge of

it.--DESCARTES.

_Rules for the Direction of the Mind;

The Philosophy of Descartes [Torrey]

(New York, 1892), p. 68._

=1875.= The ancients studied geometry with reference to the

_bodies_ under notice, or specially: the moderns study it with

reference to the _phenomena_ to be considered, or generally. The

ancients extracted all they could out of one line or surface,

before passing to another; and each inquiry gave little or no

assistance in the next. The moderns, since Descartes, employ

themselves on questions which relate to any figure whatever. They

abstract, to treat by itself, every question relating to the

same geometrical phenomenon, in whatever bodies it may be

considered. Geometers can thus rise to the study of new

geometrical conceptions, which, applied to the curves

investigated by the ancients, have brought out new properties

never suspected by them.--COMTE.

_Positive Philosophy [Martineau], Bk. 1,

chap. 3._

=1876.= It is astonishing that this subject [projective geometry]

should be so generally ignored, for mathematics offers nothing

more attractive. It possesses the concreteness of the ancient

geometry without the tedious particularity, and the power of the

analytical geometry without the reckoning, and by the beauty of

its ideas and methods illustrates the esthetic generality which

is the charm of higher mathematics, but which the elementary

mathematics generally lacks.

_Report of the Committee of Ten on

Secondary School Studies (Chicago,

1894), p. 116._

=1877.= There exist a small number of very simple fundamental

relations which contain the scheme, according to which the

remaining mass of theorems [in projective geometry] permit of

orderly and easy development.

By a proper appropriation of a few fundamental relations one

becomes master of the whole subject; order takes the place of

chaos, one beholds how all parts fit naturally into each other,

and arrange themselves serially in the most beautiful order, and

how related parts combine into well-defined groups. In this

manner one arrives, as it were, at the elements, which nature

herself employs in order to endow figures with numberless

properties with the utmost economy and simplicity.--STEINER, J.

_Werke, Bd. 1 (1881), p. 233._

=1878.= Euclid once said to his king Ptolemy, who, as is easily

understood, found the painstaking study of the “Elements”

repellant, “There exists no royal road to mathematics.” But we

may add: Modern geometry is a royal road. It has disclosed “the

organism, by means of which the most heterogeneous phenomena in

the world of space are united one with another” (Steiner), and

has, as we may say without exaggeration, almost attained to the

scientific ideal.--HANKEL, H.

_Die Entwickelung der Mathematik in den

letzten Jahrhunderten (Tübingen, 1869)._

=1879.= The two mathematically fundamental things in projective

geometry are anharmonic ratio, and the quadrilateral construction.

Everything else follows mathematically from these two.

--RUSSELL, BERTRAND.

_Foundations of Geometry (Cambridge,

1897), p. 122._

=1880.= ... Projective Geometry: a boundless domain of countless

fields where reals and imaginaries, finites and infinites, enter

on equal terms, where the spirit delights in the artistic balance

and symmetric interplay of a kind of conceptual and logical

counterpoint,--an enchanted realm where thought is double and

flows throughout in parallel streams.--KEYSER, C. J.

_Lectures on Science, Philosophy and

Arts (New York, 1908), p. 2._

=1881.= The ancients, in the early days of the science,

made great use of the graphic method, even in the form of

construction; as when Aristarchus of Samos estimated the distance

of the sun and moon from the earth on a triangle constructed as

nearly as possible in resemblance to the right-angled triangle

formed by the three bodies at the instant when the moon is in

quadrature, and when therefore an observation of the angle at the

earth would define the triangle. Archimedes himself, though he

was the first to introduce calculated determinations into

geometry, frequently used the same means. The introduction of

trigonometry lessened the practice; but did not abolish it. The

Greeks and Arabians employed it still for a great number of

investigations for which we now consider the use of the Calculus

indispensable.--COMTE, A.

_Positive Philosophy [Martineau], Bk. 1,

chap. 3._

=1882.= A mathematical problem may usually be attacked by what is

termed in military parlance the method of “systematic approach;”

that is to say, its solution may be gradually felt for, even

though the successive steps leading to that solution cannot be

clearly foreseen. But a Descriptive Geometry problem must be seen

through and through before it can be attempted. The entire scope

of its conditions, as well as each step toward its solution, must

be grasped by the imagination. It must be “taken by assault.”

--CLARKE, G. S.

_Quoted in W. S. Hall: Descriptive

Geometry (New York, 1902), chap. 1._

=1883.= The grand use [of Descriptive Geometry] is in its

application to the industrial arts;--its few abstract problems,

capable of invariable solution, relating essentially to the

contacts and intersections of surfaces; so that all the

geometrical questions which may arise in any of the various arts

of construction,--as stone-cutting, carpentry, perspective,

dialing, fortification, etc.,--can always be treated as simple

individual cases of a single theory, the solution being certainly

obtainable through the particular circumstances of each case.

This creation must be very important in the eyes of philosophers

who think that all human achievement, thus far, is only a first

step toward a philosophical renovation of the labours of mankind;

towards that precision and logical character which can alone

ensure the future progression of all arts.... Of Descriptive

Geometry, it may further be said that it usefully exercises the

student’s faculty of Imagination,--of conceiving of complicated

geometrical combinations in space; and that, while it belongs to

the geometry of the ancients by the character of its solutions,

it approaches to the geometry of the moderns by the nature of the

questions which compose it.--COMTE, A.

_Positive Philosophy [Martineau], Bk. 1,

chap. 3._

=1884.= There is perhaps nothing which so occupies, as it were,

the middle position of mathematics, as trigonometry.

--HERBART, J. F.

_Idee eines ABC der Anschauung; Werke

(Kehrbach) (Langensalza, 1890), Bd. 1,

p. 174._

=1885.= Trigonometry contains the science of continually

undulating magnitude: meaning magnitude which becomes alternately

greater and less, without any termination to succession of

increase and decrease.... All trigonometric functions are not

undulating: but it may be stated that in common algebra nothing

but infinite series undulate: in trigonometry nothing but

infinite series do not undulate.--DE MORGAN, A.

_Trigonometry and Double Algebra

(London, 1849), Bk. 1, chap. 1._

=1886.= Sin²φ is odious to me, even though Laplace made use of it;

should it be feared that sinφ² might become ambiguous, which would

perhaps never occur, or at most very rarely when speaking of sin

(φ²), well then, let us write (sinφ)², but not sin²φ, which by

analogy should signify sin(sinφ).--GAUSS.

_Gauss-Schumacher Briefwechsel, Bd. 3,

p. 292; Bd. 4, p. 63._

=1887.= Perhaps to the student there is no part of elementary

mathematics so repulsive as is spherical trigonometry.--TAIT, P. G.

_Encyclopedia Britannica, 9th Edition;

Article “Quaternions.”_

=1888.= “Napier’s Rule of circular parts” is perhaps the happiest

example of artificial memory that is known.--CAJORI, F.

_History of Mathematics (New York,

1897), p. 165._

=1889.= The analytical equations, unknown to the ancients, which

Descartes first introduced into the study of curves and surfaces,

are not restricted to the properties of figures, and to those

properties which are the object of rational mechanics; they apply

to all phenomena in general. There cannot be a language more

universal and more simple, more free from errors and obscurities,

that is to say, better adapted to express the invariable

relations of nature.--FOURIER.

_Théorie Analytique de la Chaleur,

Discours Préliminaire._

=1890.= It is impossible not to feel stirred at the thought of

the emotions of men at certain historic moments of adventure and

discovery--Columbus when he first saw the Western shore, Pizarro

when he stared at the Pacific Ocean, Franklin when the electric

spark came from the string of his kite, Galileo when he first

turned his telescope to the heavens. Such moments are also

granted to students in the abstract regions of thought, and high

among them must be placed the morning when Descartes lay in bed

and invented the method of co-ordinate geometry.--WHITEHEAD, A. N.

_An Introduction to Mathematics (New

York, 1911), p. 122._

=1891.= It is often said that an equation contains only what has

been put into it. It is easy to reply that the new form under

which things are found often constitutes by itself an important

discovery. But there is something more: analysis, by the simple

play of its symbols, may suggest generalizations far beyond the

original limits.--PICARD, E.

_Bulletin American Mathematical Society,

Vol. 2 (1905), p. 409._

=1892.= It is not the Simplicity of the Equation, but the

Easiness of the Description, which is to determine the Choice of

our Lines for the Constructions of Problems. For the Equation

that expresses a Parabola is more simple than that that expresses

the Circle, and yet the Circle, by its more simple Construction,

is admitted before it.--NEWTON.

_The Linear Constructions of Equations;

Universal Arithmetic (London, 1769),

Vol. 2, p. 468._

=1893.= The pursuit of mathematics unfolds its formative power

completely only with the transition from the elementary subjects

to analytical geometry. Unquestionably the simplest geometry and

algebra already accustom the mind to sharp quantitative thinking,

as also to assume as true only axioms and what has been proven.

But the representation of functions by curves or surfaces reveals

a new world of concepts and teaches the use of one of the most

fruitful methods, which the human mind ever employed to increase

its own effectiveness. What the discovery of this method by Vieta

and Descartes brought to humanity, that it brings today to

every one who is in any measure endowed for such things: a

life-epoch-making beam of light [Lichtblick]. This method has its

roots in the farthest depths of human cognition and so has an

entirely different significance, than the most ingenious artifice

which serves a special purpose.--BOIS-REYMOND, EMIL DU.

_Reden, Bd. 1 (Leipzig, 1885), p. 287._

=1894.=

_Song of the Screw._

A moving form or rigid mass,

Under whate’er conditions

Along successive screws must pass

Between each two positions.

It turns around and slides along--

This is the burden of my song.

The pitch of screw, if multiplied

By angle of rotation,

Will give the distance it must glide

In motion of translation.

Infinite pitch means pure translation,

And zero pitch means pure rotation.

Memorabilia Mathematica; or, the Philomath's Quotation-Book · 第 15 / 17 章