Books will be issued only on presentation
of proper library cards.
Unless labeled otherwise, books may be
retained for fut that they are entirely new departures, arising out of
ur increasing knowledge of and command over the
orces of the universe. Many of these advances have
Jready led to developments of the most startling kind,
jiving us such marvellous powers, and such extensions
our normal senses, as would have been incredible, and
almost unthinkable even to our greatest men of science,
a hundred years ago. We begin with the simplest of
these advances, those which have given us increased
facilities for locomotion.
The younger generation, which has grown up in the
era of railways and of ocean-going steamships, hardly
realize the vast change which we elders have seen, or
how great afcd fundamental that change is. Even in my
own, boyhood the wagon for the poor, the stag coach
for the middle class, and the post-chaise for the wealthy,
were the universal means of coiomrinicatia^ there
1 '
THE WONDERFUL CENTURY.
Stockton and Darlington opened in 1825, end the Liver-
pool and Manchester line opened in 1830. The yellow
post-chaise, without any driving seat, but wSira postilion
dressed like a jockey riding one of the pair of horses,
was among the commonest sights on our main roads; and
together with the hundreds of four-horse mail and stage
coaches, the guards carrying horns or bugles which were
played while passing through every town or village, gavei
a stir and liveliness and picturesqueness to rural life
which is now almost forgotten.
When I first went to London (I think about 1835)
there was still not a mile of railroad in England, excepj
the two above-named, and none between London anc]
any of our great northern or western cities were ever
seriously contemplated. The sites of most of our grea
London railway termini were then on the very outskirt
of the suburbs; Chalk Farm was a genuine farmhouse
and Primrose Hill was surrounded by open fields.
A few years later (in 1837-38) I was living neai
Leighton Buzzard while the London and Birmmghan
Eailway, the precursor of the present London and
"Western system, was in process of construction; and
when the first section was opened to Watford, I travelled
by it to London, third-class,. in what is now an ordinary
goods truck, with neither roof nor seats, nor any other
accommodation than is now given to coal, iron, and mis-
cellaneous goods. If it rained, or the wind waa cold,
the passengers sat on the floor and protected themselves
as they could. Second-class carriages were then what
the very worst of the third-class are or were a few years
ago closed in, but low and nearly dark, witt plain
wooden seats while the first class were exactly likfo the
MODES OF TRAVELLING.
bodies of three stage coaches joined together. The open
passenger tracks were the cause of much misery, and a
few deaths from exposure, before they were somewhat
improved; but even then there was evidently a dread of
making them too comfortable, so a roof was put to them,
also seats, and the sides a little raised but open at the
top, about equal in comfort to our present cattle trucks.
At last, after a good many years, the despised third-class
passengers were actually provided with carriages of the
early second-class type; and it is only in comparatively
recent times that the greater railway companies realized
the fact that third-class passengers were so numerous as
to be more profitable than the other two combined, and
that it was worth while to give them the same comfort,
if not the same luxury, as those who could afford to
travel more expensively.
The continuous progress in speed and comfort is mat-
ter of common knowledge, and nothing more need be
said of it here. The essential point for our consideration
is, the fundamental and even revolutionary nature of
the change that has been wholly effected during the
present century. In all previous ages the only modes of
travelling or of conveying goods for long distances were
by employing either men or animals as the carriers.
"Wherever the latter were not used all loads had to be
carried by men, as is still the case over a large part of
-Africa, and as was the case over almost the whole of
America before its discovery by the Spaniards. ^
But throughout Europe and Asia the horse was -do-
mesticated in very early times, and was used for ri$bg
and in drawing watt chariots; and throughout the Mddle
6 Tfiffi WONDERFUL CENTORY. ctti*.i.
various kinds of goods and produce, and saddle horses
for riding. All journeys were then made on horseback
and it was in comparatively recent times that wheelec
vehicles for travelling in came into general use in Eng
land. The very first carriage was made for Queer
Elizabeth in 1568; the first that plied for hire in London
were in 1625, and the first stage coaches in 1C59,
But chariots drawn by horses were used, both in wai,
and peace, by all the early civilized peoples. Pharaoh
made Joseph ride in a chariot, and he sent wagons to
bring Jacob, with his children and household goods, to
Egypt. A little later chariots were sent by the Syrians)
as tribute to Pharaoh. Homer describes Telemachus as|
travelling from Pylos to Sparta in a chariot provided for
him by Nestor:
" The rage of thirst and hunger now suppressed,
The monarch turns him to his royal guest;
And for the promis'd journey bids prepare
The smooth-haired horses, and the rapid car."
It is clear, therefore, that in the earliest historic times
all the various types of wheeled vehicles were used f or
war, for racing, for travelling, and for the conveyance of
merchandise. They must also have been used through-
out a large part of Europe, since Caesar found our Brit-
ish ancestors possessed of war-chariots, which they man-
aged with great skill, implying a long previous acquaint-
ance with the domesticated horse and its use in humbler
wheeled vehicles.
Thus, throughout all past history the modes of travel-
ling were essentially the same, and an ancient Greek or
Roman ; Egyptian, or Assyrian, could travel as quickly
MODES OP TRAVELLING.
and as conveniently as could Englishmen down to the
latter part of the eighteenth century. It was mainly a
question of roads, and till the beginning of the nine-
teenth, century our roads were for the most part far in-
ferior to those of the Eomans. It is, therefore, not
improbable that during the Eoman occupation of Brit-
ain the journey from London to York could have
been made actually quicker than a hundred and fifty
years ago,
"We see, then, that from the earliest historic, and even
in prehistoric times, till the construction of our great
railways in the second quarter of the present century,
there liad been absolutely no change in the methods of
human locomotion; and the speed for long distances
must have been limited to ten or twelve miles an hour
even under the most favorable conditions, while gener-
ally it must have been very much less. But the railroad
and steam-locomotive, in less than fifty years, not only
raised the speed to fifty or sixty miles an hour, but ren-
dered it possible to carry many hundreds of passengers
at once with punctuality and safety for enormous dis-
tances, and with hardly any exposure or fatigue. For
the civilized world travelling and the conveyance of
goods have been revolutionized, and by means which
were probably neither anticipated nor even imagined
fifty years before.
Dr. Erasmus Darwin, who predicted steam carriages,
had apparently no conception of the possibility of rail-
roads, the enormous cost of which would have seemed to
be prohibitory. And we have by no means yet folly
developed their possibilities, since even now a n railroad
Wmade on which we iai^M <> 4i^^; : teHi^l > more
THE WONDERFUL CENTURY.
than a hundred miles an hour, it being merely a questi
of expense.
In steam navigation there has "been a very similar
course of events, with the same characteristic of a com-
pletely new departure, leading to unknown develop-
ments and possibilities. From the earliest dawn of his-
tory men used rowing or sailing vessels for coasting
trade or for crossing narrow seas. The Carthaginians
sailed nearly to the equator on the west coast of Africa,
and in the eleventh century the Northmen reached
North .America on the coast of New England. Exactly
five hundred years ago Vasco de Gama sailed from Por-
tugal round the Cape of Good Hope to India, and in the
next century Columbus and his Spanish followers crossed
the Atlantic in its widest part to the West 'Indies and
Mexico. From that time sailing ships were gradually
improved, till they culminated in our magnificent
frigates for war purposes and the clipper ships in the
China and Australian trade, which were in use up to
the middle of the century. But during all this long
course of development there was no change whatever in
principle, and the grandest three-decker or full-rigged
clipper ship was but a direct growth, by means of an
infinity of small modifications and improvements, from
the rudest sailing boat of the primeval savage.
Then, at the very commencement of the present cen-
tury, the totally new principle of steam-propulsion be-
gan to be used, at first experimentally and with many
failures, on rivers, canals, and lakes, till about the year
1815 coasting steamships of small size came into pretty
general use. These were rapidly improved; but it w#s
not till the yeax 1838 that the Great Western, of 1340
MODES OF TRAVELLING.
tons and 400 horse-power, made the passage from Bristol
to New York in fourteen days, and this inaugurated the
system of ocean steam-navigation, which has since devel-
oped to such an enormous extent. The average speed
then attained, of about ten miles an hour, has now been
more than doubled, and is still increasing. But the
horse-power needed to attain this high speed has in-
creased in much greater proportion; and it is only the
much greater size and capacity, both for passengers and
goods, that render such high speeds and enormous con-
sumption of coal profitable. Some of the smaller steel-
built war-ships torpedo-boats and torpedo-destroyers
have considerably exceeded thirty miles an hour, and the
limit of speed is probably not yet reached. Many sug-
gested forms of vessels, such as the cigar-shaped and the
roller-boats, have not been adequately tried; and there
are other suggested forms by means of which greater
steadiness and speed may yet be obtained.
Almost as remarkable as our railroads and steamships
is the new method of locomotion by means of the bicycle
and tricycle. The principle is old enough, but the per-
fection io which these vehicles have BOW attained has
been rendered possible by tixe continuous growth of all
kinds of delicate tools and machines required in the con-
struction of the infinitely varied forms of steam-engines,
dynamos, and other rapidly-moving machinery. In the
last century it would not have been possible to bonstruct
a modern first-class bicycle, even if any genius Kad in-
vented it, except at a cost of several hundred pounds.
The combination of strength, accuracy, and lightness
vcmld not then have been attainable. It is a very inter-
esting fact that three out of the four methods of rapid
10 THE WONDERFUL CENTURY. ciu*.i.
locomotion we now possess should have attained about
the same maximum speed. The racehorse, the steam-
ship, and the bicycle, have each of them reached thirty
miles an hour. The horse is, however, close upon, if it
has not actually attained, its utmost limits; the bicycle
can already beat the horse for long distances, and will
certainly go at higher speeds for short ones; while the
steamship will also go much quicker, though how much
no one can yet say. The greatest possibilities are with
the bicycle, driven by electric power or compressed air,
by which means, on a nearly straight and fairly level,
asphalt track, no doubt fifty miles an hour will soon be
reached.
We see, then, that during the nineteenth century
three distinct modes of locomotion have been originated
and brought to a high degree of perfection. Two of
them, the locomotive and the steamship, are altogether
different in principle from what had gone before. Up
to the very times of men now living, all our locomotion
was on the same old lines which had been used for thou-
sands of years. It had been improved in details, but
without any alteration of principle and without any very
great increase of efficiency. The principles on which
our present methods rest are new; they already far sur-
pass anything that could be effected by the older
methods; with wonderful rapidity they have spread over
the whole world, and they have in many ways modified
the habits and even the modes of speech of all civilized
peoples.
This vast change in the methods of human locomotion,
already so ubiquitous that by the younger generation
their absence rather than their presence is considered re-
CHAP. i. MODES OF TRAVELLING. 11
markable, has been almost wholly effected within the
writer's memory, and is of itself sufficiently striking and
important to justify the appellation of " The Wonderful
Century" to that period which witnessed its rise, its
progress, and its maturity of development
OHAPTEE H.
/
LABOB-SAVITO MACHINERY.
Wonderful chair ! "Wonderful horses ! Wonderful people !
Whirr i whirr ! all by wheels ! Whizz ! whizz ! all by steam.
! JEfotJtm.
Work work work
Till the brain begins to swim ;
Work work work
Till the eyes are heavy and dim !
Seam, and gusset and band,
Band and gusset and seam,
Till over the buttons I fall asleep,
And sew them on in a dream !
Hood.
THE invention and partial development of much of
our modern machinery dates from the last century, and
our most advanced appliances for the manufacture of
the various textile fabrics and hardware are mostly im-
provements of, or developments from, the older ma-
chines. These, taken in connection with, the great im-
provements in steam-engines, have multiplied many
times over the efficiency of human labor, but do not
otherwise specially interest us here. There are, how-
ever, a few inventions which have the character of quite
new departures, since not only do they greatly diminish
labor but they perform, by mechanical contrivances,
operations which had been supposed to be beyond the
power of machinery to execute. The more prominent
of these are the sewing machine, the typewriter^ and h^
LABOR-SAVING MACHINERY. la
combined reaping, thrashing, and winnowing machine,
of which a brief account will be given.
The sewing machine, now so common, exercised the
ingenuity of mechanicians for a long period before it
arrived at sufficient perfection to be suitable for general
use* The earlier machines were for embroidering only;
then, about 1790, one was made for stitching shoes and
other leather work, but it does not seem to have come
into general use. A crocheting machine was patented
in 1834; somewhat later one for rough basting; but it
was not till 1846 that the first effective lock-stitch sew-
ing machine was made by Elias Howe, of Cambridge,
Mass. Henceforth sewing machines were rapidly im-
proved and adapted to every variety of work; but the
difficulty of the problem to be solved is shown by the
unusually long process of gradual development, much
of the mechanical talent of both hemispheres being
occupied for nearly a century before the various ma-
chines so familiar to-day were perfected. There are
now special machines for making button-holes and for
sewing on buttons, for carpet-sewing, for pattern-sewing,
for leather work, and for the special operations required
in the making and repairing of shoes. Boot and shoe-
making by machinery, in large factories, has entirely
grown up since the sewing-machine was proved to be
adapted for almost every kind of sewing work. As a
result, machine-made boots and shoes are very cheap,
but they are usually of inferior quality to the old hand-
made articles; and first-class work is quite as dear as it
was fifty or sixty years ago, or even dearer.
* typewriter is a still later invention,, and though
'fe&s difficult than" $i& sewing mk^Ep.^ yet it
14 THE WOOT>ERFUL CEOTUBY. OHAP.II.
involves more complex motions and adjustments, so that
the perfection- it has so quickly attained is very remarka-
ble. If we consider that about sixty separate types, in-
cluding small letters, capitals, spaces, stops, etc., have to
be so arranged and so connected as to be brought in any
order whatever to a definite position, so as to form the
successive letters and spaces in lines of printed charac-
ters and then, being properly inked, must be brought
into contact with the paper so as to produce a clear im-
pression, and that all the motions of the machinery re-
quired must be the result of a single pressure on a key
for each letter, following one another as rapidly as
possible, we shall have some idea of the difficulties which
have had to be overcome. Tet, so great are the re-
sources of modern mechanism, and the ingenuity of our
mechanists, that the required result has been attained
in many different ways, so that we may now choose
between half a dozen forms of typewriters, no one
of which seems to be very markedly superior to the
rest.
More important, perhaps, to mankind generally, are
the harvesting machines, which render it possible to
utilize one or two fine days to secure a harvest. Reap-
ing machines have long been used in this country, and
they were followed by combined reapers and binders,
which left the crop ready for carting to the barn. But
this, when the distance was great, did not save the grain
from injury by wet, besides requiring much labor and a
careful process of stacking to preserve it. In America
a harvesting machine has been brought to perfection,
which not only reaps the grain, but threshes it, winnows
it, and delivers it into sacks ready for the granary or thq
era*. LABOR-SAVING MACHINERY. 15
market, at one operation. This machine, with two men,
will, in one fine day, secure the crop from ten or fifteen
acres, with a minimum of labor. In the great wheat-
fields of California and Australia, with an almost uni-
formly dry climate at harvest time, it is this saving of
labor which is the chief consideration; but in our
treacherous climate, where a few days 7 delay may mean
the partial or complete ruin of the crop, such machines
will be doubly valuable by enabling farmers to utilize to
the utmost every fine day after the grain is ripe. I had
the pleasure of seeing this wonderful machine at work
in California in 1887. It was propelled by sixteen small
mules harnessed behind, so as not to be in the way; but
steam power is now used. Considering what it effected,
it was wonderfully light, compact, and simple; and when
agriculture is treated as a work of national importance,
such machines will render us, to a considerable extent,
independent of the weather, and will therefore become a
necessity.
The three mechanical inventions here briefly de-
scribed were conceived in the first half, and brought to
perfection in the second half of the century. They
each mark a new departure in human industry, inas-
much as they effect, by means of machinery and at one
operation, what had previously been performed by hu-
man labor directed by a hand or arm rendered skilful
by long practice, and sometimes requiring several dis-
tinct operations. They had been thus performed dur-
ing the whole preceding period of human history, or so
long as the particular kind of work had been do&e; so
that, though of less general use and of less importance,
they have the same distinguishing features which we
16 THE WONDERFUL CENTURY. CHI*, it
have found to characterize our new methods of loco-
motion.
There are, of course, innumerable other remarkable
mechanical inventions of the century in almost every
department of industry such as the Jacquard loom for
pattern-weaving, revolvers and machine-guns, iron ships,
screw propellers, etc. ; while machinery has been exten-
sively applied to watch-making, screw-cutting, nail-mak-
ing, printing, and a hundred other purposes. But none
of these are of very high importance in themselves, or
possess the special characteristics of being new and quite
distinct departures from what has been done before, and
they cannot therefore rank individually among those
greater discoveries which pre-eminently distinguish the
nineteenth century.
OHAPTEE HI.
THE CONVEYANCE OF THOUGKHT*
Speak the word and think the thought,
Quick 'tis as with lightning caught
Over, under, lands or seas
To the far antipodes.
*
I sent a message to my dear
A thousand leagues and more to Her
The dumb sea-levels thrilled to hear,
And Lost Atlantis bore to Her.
Kipling.
THE history of the progress of communication between
persons at a distance from each other has fc gone through
three stages which are radically distinct. At first it
was dependent on the voice or on gestures, and a message
to a friend (or enemy) at a distance could only be sent
through a messenger, and was liable to distortion through
failure of memory. The heralds and ambassadors of
early times thus communicated orders from kings to their
subjects, or conveyed messages from one king to another.
Then came the invention of writing, and a new era of
communication began. Letters were capable of convey-
ing secret information and copious details, which could
not be safely intrusted to the uncertain memory of an
intermediary; and a single messenger could convey a
large number of letters to various persons on the way to
his ultimate destination. Henceforth the progress of
communications was bound up with that of locomotion,
18 THE WONDERFUL CENTURY. CHAP. in.
and, as civilization advanced, arrangements were made
for the conveyance of letters at a comparatively small
cost. A Post Office for the public service was first estab-
lished by some Continental merchants in the fourteenth
century; but it was not till the time of Charles I. that
anything of the kind was to be found in England, and
then it was mainly for the purpose of keeping up a com-
munication between London and Edinburgh, and the
intervening large towns, for Government purposes. It
was, however, the starting-point of our existing postal
system, which has been gradually extended under the
direction of the King's Postmaster General, and has con-
tinued to be a Government monopoly to our day. The
letters were carried on horseback till 1783, when mail
coaches were first introduced; and these led to a great
improvement in our main roads, and the extension of
the postal service to every town and village in the
kingdom.
But even with good roads and mail coaches, the actual
time taken in the despatch of a letter to a distant place
was little if any less than had been possible from the
earliest times, by means of relays of runners on foot or
by swift horsemen. The improvement consisted in the
regularity and economy of the postal service. The in-
troduction of railways and steamships enabled much
greater speed to be secured; but the greatest and most
beneficial improvement in the administration of the
Post Office was that inaugurated by Eowland Ball in
1840. The rule then first introduced, of an uniform
charge irrespective of distance, is one of those entirely
new departures so many of which characterize our cen-
tury, and which not only produce immediate beneficial
m. THE CONVEYANCE OF THOUGHT. 1&
effects, but are the starting-points of various unforeseen
developments. It was founded in this case on a careful
estimate of the various items which make up the cost of
the carriage and delivery of each letter, and it was shown
that the actual conveyance, even for the greatest dis-
tances, was the smallest part of the cost when the num-
ber of letters is large, the chief items of expense being
the office work the sorting, stamping, packing, etc.
and the final delivery, all of which are quite independent
of the distance the letter is carried. The old system,
therefore, of increasing the charge for postage in propor-
tion to distance was altogether unreasonable, because the
cost of conveyance was hardly perceptibly increased;
and if the Post Office was considered to be a public
service for the public benefit only, the people had a right
to demand that they should pay only in proportion to
the cost. Yet the principle was not at first, and is not
even now, fully carried out. Tor thirty years, from
1840 to 1871, the postage was increased equally with
each, successive increment of weight, the half -ounce let-
ter being a penny, while one of two ounces was four-
pence. But as the chief items of expense the office
work and delivery were the same, or nearly the same
in both cases, the double or quadruple charge was en-
tirely opposed to the principle on which the uniform rate
was originally founded. Accordingly, in 1871, when
an ounce letter was first carried for a penny, the charge
for two ounces was fixed at three halfpence, while four
ounces was taken for twopence. This accepted aad
<3ommon-$ense principle, however, has not yet been ap-
plied to the charges of the Postal Union, so that a lette*
is a fraction over the talf-ounc^ & charged five
SO THE WONDERFUL CEHTUBY.
pence, or double, and one over an ounce and a half ten-
pence, or four times that of the half-ounce letter, al-
though an extra halfpenny would probably cover the
extra cost of the service in both cases.
The same inability of the official mind to carry out an
admitted principle is seen also in the case of Postal
Orders. The cost to the Post Office of receiving and
paying money is exactly the same whether the amount
is eighteenpence or fifteen shillings, and there is neither
justice nor common-sense in charging three times as
much in the latter case. There is no risk, because the
money is paid in advance; and as the amounts taken in
and paid out for postal orders must be approximately
equal, it is difficult to see what justification there is for
making any difference in charge. The same objection
applies to Money Orders; and as there is doubtless a cer-
tain percentage of both which, from various causes, axe
never presented for payment, the profit to the Post Office
must be greater in case of the higher amounts, which is
another reason why these should not be exceptionally
taxed. When the railways are taken over by the state,
to be worked for the good of the community only, the
principle will admit of great extension, each increment
of distance being charged at a lower rate, just as is each
increment of weight in our inland letters.
The third stage in the means of communication, when
by means of electric signals it was rendered independent
of locomotion, is that which has especially distinguished
the present century. The electric telegraph serves us as
a new sense, enabling us to communicate with friends at
the other side of the globe almost as rapidly and as easily
as if they were in different parts of the same town,
CHAP. m. THE CONVEYANCE OF THOUGHT. 81
means of communication we now use daily would have
been wholly inconceivable to our ancestors a hundred
years ago.
About the middle of the last century it was perceived
by a few students of electricity that it afforded a means
of communication at a distance; but it was not till the
y *r 1837 that the efforts of many simultaneous workers
Overcame the numerous practical difficulties, and the
first electric telegraph was established. Its utility was
so great, especially in the working of the railways then
being rapidly extended over the kingdom, that it soon
came into general use; but hardly anyone at first thought
that it would ever be possible to lay wires across the
ocean depths to distant continents. Yet, step by step,
with wonderful rapidity, even this was accomplished.
The first submarine line was laid from Dover to Calais
in 1851; and only five years afterward, in 1856, a com-
pany was formed to lay an electric cable across the
Atlantic. The cable, 2500 miles long and weighing a
ton per mile, was successfully laid, in 1858, from Ire-
land to Newfoundland; but owing to the weakness of
the electric current, and perhaps to imperfections in the
cable, it soon became useless, and had to "be abandoned.
After eight years more of invention and experiment,
another cable was successfully laid in 1866; and there
are now no less than fourteen lines across the Atlantic,
while all the other oceans have been electrically bridged,
so that messages can be sent to almost any part of the
globe at a speed which far surpasses the imaginary power
of Shakespeare's sprite Ariel, who boasted that he could
" put a gia?dle round about the earth in forty minutes."
are ww able to receive accounts of great events d*
THE WONDERFUL CENTURY.
most while they are happening on the other side of the
globe; and, owing to difference of longitude, we some-
times can hear of an event apparently before it has hap-
pened. If some great official were to die at Calcutta at
sunset, we should receive the news soon after noon on
the same day.
As a result of the numerous experimental researches
necessitated for the continuous improvement of the elec-
tric telegraph, the telephone was invented, an even more
marvellous and unexpected discovery. By it, the hu-
man voice, in all its countless modifications of quality
and musical tone, and its most complex modulations dur-
ing speech, is so reproduced at a distance that a speaker
or singer can be distinctly heard and understood hun-
dreds of miles away. This is not an actual transmission
of the voice, as in the case of a speaking-tube, but a true
reproduction by means of two vibrating discs: the one
set in motion by the speaker, while the electric current
causes identical vibrations in the similar disc at the end
of the line, and these vibrations reproduce the exact
tones of the voice so as to be perfectly intelligible. At
first telephones could only be worked successfully for
short distances, but by continuous improvements the dis-
tance has been steadily increased, so that in America
th^re is a telephone line now in operation between New
Tork and Chicago, cities about a thousand miles apart.
Those who have read Mr. Bellamy's wonderful story,
" Looking Backward," will remember the concerts con-
tinually going on day and night, with telephonic connec-
tions to every house, so that everyone could listen to the
very best obtainable music at will. But few persons are
fiware that a somewhat similar use of the telephone is
CHAP. ni. THE CONVEYANCE OF THOUGHT. 23
actually in operation at Buda Pestli in tlie form of a
telephonic newspaper. At certain fixed Hours through-
out the day a good reader is employed to send definite
classes of news along the wires which are laid to sub-
scribers' houses and offices, so that each person is able
to hear the particular items he desires, without the delay
of its being printed and circulated in successive editions
of a newspaper. It is stated that the news is supplied to
subscribers in this way at little more than the cost of a
daily newspaper, and that it is a complete success.
We thus see that during the present century two dis-
tinct modes of communication with persons at a distance
have been discovered and brought into practical use,
both of which are perfectly new departures from the
niethods which, with but slight modifications, had been
in use since that early period when picture-writing or
hieroglyphics were first invented.
In the facilities and possibilities of communication
with our fellow-men all over the world, the advance
made in the present century is not only immensely
greater than that effected during the whole preceding
period of human history, but is even more marvellous in
its results. And it is also much greater in amount than
the almost simultaneous advance in facilities for loco-
motion, great as these have been.
CHAPTEE IV,
FIBE A1STD LIGHT.
Put out the light, and then Put out the light !
If I quench thee, thou flaming minister,
I can again thy former light restore,
Should I repent me : but once put out thy light,
Thou cunning'st pattern of excelling nature,
I know not where is that Promethean heat
That can thy light relume.
Othello.
IT seems probable that the discovery of the use of fire,
and of some mode of producing it at will, constituted
th& first important advance of primitive man toward ob-
taining that command over nature which, we term civili-
zation. How long ago it is since that first step was
taken, we have no means of determining. The palaeo-
lithic cave-dwellers made use of fire, and no tribes of
men have been found who were wholly unacquainted
with it. It was probably first utilized in volcanic dis-
tricts where sticks may often be ignited by thrusting
them into cavities in old lava streams. In other regions,
trees are often ignited when struck by lightning; and
when this was first observed, the agreeable warmth, the
ease with which the fire could be kept up by adding fresh
fuel, the cheerful blaze at night, and the pleasant taste
imparted to many kinds of food by roasting, would al-
most certainly lead to its careful preservation, and its
distribution to other families and tribes. When once
used, the inconvenience of losing it would be so great,
24
FIRE AND LIGHT.
that any clew to its mode of production would be fol-
lowed up. It is said that trees are sometimes ignited by
the friction of dry branches which happen to touch each
other, when violently rubbed together during a strong
wind. When this was observed for the first time by
some thoughtful savage, and he actually found that
strong rubbing did make things hot, he would be en-
couraged to use his utmost -efforts to imitate the effect
produced by nature. After many unsuccessful trials, he
would at length succeed; and the important news would
be rapidly communicated to adjacent tribes, and thus
spread over a whole continent. As a matter of fact, this
method of producing fire by friction is that most com-
mon among savages in all parts of the world; and since
it requires only materials that are almost everywhere at
hand, it descended even to some civilized peoples. It is,
however, a rather troublesome process, requiring a con-
siderable amount of skill and perseverance; hence some
of the lowest savages, such as the Tasmanians, are said
to have been without the knowledge of it, keeping their
fires constantly alight, or, when accidentally esdin-
guished, obtaining it from some adjacent tribe. Per-
haps, however, the dampness of their forests rendered it
practicable only during very dry seasons.
The more convenient method of striking a light by
the use of flint, steel, and tinder, probably originated
after iron, was first made, and soon became adopted by
all civilised people, and by many savages who possessed
ironj and this method continued in use from the times
of prehistoric man through all the ages of barbarism and
dvilkatiosa down to the early part of this century, and
the .process raderwent hardly any improvement during
THE WONDEKFlfL CENTURY.
that long period. One of the most vivid recollections of
my childhood is of seeing the cook make tinder in the
evening, by burning old linen rags, and in the morning,
with flint and steel, obtaining the spark which, by careful
blowing, spread sufficiently to ignite the thin brimstone
match from which a candle was lit and fire secured for
the day. The process was, however, sometimes, . a
tedious one, and if the tinder had accidentally got damp,
or if the flint were worn out, after repeated failures a
light had to be obtained from a neighbor. At that time
there were few savages in any part of the world but
could obtain fire as easily as the most civilized of
mankind.
At length, after the use of these rude methods for
many thousand years, a great discovery was made which
revolutionized the process of fire-getting. The proper-
ties of phosphorus were known to the alchemists, and it
is strange that its ready ignition by^f riction was not made
use of to obtain fire at a much earlier period. It was,
however, both an expensive and a dangerous material,
and though about a hundred years ago it began to be
made cheaply from bones, it was not used in the earliest
friction matches. These were invented in 1827, or a
little earlier, by Mr. John Walker, a chemist and drug-
gist of Stockton-on-Tees, and consisted of wood splints,
dipped in chlorate of potash and sulphur mixed with
gum, which ignited when rubbed on sandpaper* Two
years later the late Sir Isaac Holden invented a similar
match. About 1834, phosphorus began to be used with
the other materials to cause more easy ignition, and by ,
1840 these matches became so cheap as to come into gen**
eral u&e in place of the old flint and steel. They hayj^
CHAT. iv. FIRE AND LIGHT. 27
since spread to every part of tlie world, and their pro-
duction constitutes one of the large manufacturing in-
dustries of England, Sweden, and many other coun-
tries.
Here again we have an invention that is not a modi-
fication of the older mode of obtaining fire, but a new
departure, possessing such great advantages that it
rapidly led to the almost total abandonment of the old
methods in every civilized country, as well as in many
of the remotest and least civilized parts of the world.
For many thousands of years the means of obtaining
fire remained almost unchanged over the whole world,
till, only sixty years ago, a discovery which at the time
seemed of but little importance has led to a quicker and
easier process, which is so widely adopted that millions
of persons in all civilized countries make use of it every
day of their lives.
Coming now to the use of fire as a light-giver, we find
ihat an even greater change has taken place in our time.
The first illuminants were probably torches made of resi-
nous woods, which will give a flame for a considerable
time. Then the resin exuding from many kinds of trees
would be collected and applied to sticks or twigs, or to
some fibrous materials tied up in bundles, such as are still
used by many savage peoples, and were used in the old
baronial halls. For out-door lights torches were used
almost down to our times, an indication of which is seen
in the iron torch-extinguishers at the doors of many of
the older West End houses; while, before the introduc-
tion of gas, link-boys were as common in the streets as
match-sellers are now. Then came lamps, formed of
$ay ;iwpfy holding some m^ed flniw} fat and 9
28 THE WONDERFUL CENTUKY. CHAF. iv.
fibrous wick; and, somewhat later, rushlights and
candles. Still later, vegetable oils were used for lamps,
and wax candles; but the three modes of obtaining
illumination for domestic purposes remained entirely un-
changed in principle, and very little improved, through-
out the whole period of history down to the end of the
eighteenth century. The Greek and Eoman lamps,
though in beautiful receptacles of bronze or silver, were
exactly the same in principle as those of the lowest sav-
age, and hardly better in light-giving power; and though
various improvements in form were introduced, the first
really important advance was made by the Argand
burner. This introduced a current of air into the center
of the flame as well as outside it, and, by means of a
glass chimney, a regular supply of air was kept up, and
a steady light produced. Although the invention was
made at the end of the last century the lamps were not
sufficiently improved and cheapened to come into use till
about 1830; and from that time onward many other im-
provements were made, chiefly dependent on the use of
the cheap mineral oils, rendering lamps so inexpensive,
and producing so good a light, that they are now found
in the poorest cottages.
The only important improvement in candles is due to
the use of paraffin fats instead of tallow, and of flat
plaited wicks which are consumed by the flame. In my
boyhood, the now extinct " snuffers " were in universal
use, from the common rough iron article in the kitchen
to elaborate polished steel spring-snuffers of various
makes for the parlor, with pretty metal or
trays for them to stand in. Candles are still very
used, being more portable and safer than most of
CHAP. iv. FIBE AND LIGHT. 29
paraffin oil lamps. Even our lighthouses used only
candles down to the early part of the present century.
A far more important and more radical change in our
modes of illumination was the introduction of gas-light-
ing. A few houses and factories were lighted with gas
at the very end of the last century, but its first applica-
tion to out-door or general purposes was in 1813, when
Westminster Bridge was illuminated by it, and so suc-
cessfully that its use rapidly spread to every town in the
kingdom, for lighting private houses as well as streets
and public buildings. When it was first proposed to
light London with gas, Sir Humphrey Davy is said to
have declared it to be impracticable, both on account of
the enormous size of the needful gasholders, and the
great danger of explosions. These difficulties, have,
however, been overcome, as was the supposed insupera-
ble difficulty of carrying sufficient coal in the case of
steamships crossing the Atlantic, the impossibilities of
one generation becoming the realities of the next.
Still'more recent, and more completely new in prin-
ciple, is the electric light, which has already attained a
considerable extension for public and private illumina-
tion, while it is applicable to many purposes unattainable
by other kinds of light. Small incandescent lamps are
now used for examinations of the larynx and in den-
tistry, and a lamp has even been introduced into the
stomach by which the condition of that organ can be
examined. Tor this last purpose numerous ingenious
arrangements have to be made to prevent possible in-
jury, and by means of prisms at the bends of the tube
the operator can inspect the interior of the organ under
Other internal organs have been e?r
80 THE WONDERFUL CENTURY. CHAP.IV.
plored in a similar manner, and many new applications
in this direction will no doubt be made. In illuminat-
ing submarine boats and exploring the interiors of
sunken vessels it does what could hardly be effected by
any other means.
We thus find, that whereas down to the end of the last
century our modes of producing and utilizing light were
almost exactly the same as had been in use for the pre-
ceding two or three thousand years, in the present cen-
tury we have made no less than three new departures, all
of which are far superior to the methods of our fore-
fathers. These are: (1) the improvement in lamps by
the use of the principle of the Argand burner and chim-
ney; (2) lighting by coal-gas; and (3) the various modes
of electric lighting. The amount of advance in this one
department of domestic and public illumination during
the present century is enormous, while the electric light
has opened up new fields of scientific exploration.
Whether we consider the novelty of the principles in-
volved or the ingenuity displayed in their application,
we cannot estimate this advance at less than that effected
during the whole preceding period of human history,
from that very remote epoch when fire was first taken
into the service of mankind, down to the time of men
now living among us.
CHAPTER V.
NEW APPLICATIONS OF UGKET PHOTOGRAPHY.
O portrait, bright and wonderful !
Wrought by the sun-god's pencil true ;
What grace of feature, glance of eye !
The soul itself beams out from you.
New marvel of a marvellous age 1
Apelles old, whose art 'twas said
Rivalled reality, than this
Had never limned a lovelier head. 1
THE improvements in the mode of production of light
for common use, discussed in the previous chapter, are
sufficiently new and remarkable to distinguish this cen-
tury from all the ages that preceded it, but they sink
into insignificance when compared with the discoveries
which have been made as to the nature of light itself, its
effects on various kinds of matter leading to the art of
Photography, and the complex nature of the Solar
Spectrum leading to Spectrum Analysis. This group of
investigations alone is sufficient to distinguish the
present century as an epoch of the most marvellous scien-
tific discovery.
Although Huygens put forward tib.e wave-theory of
light more than two hundred years ago, it was not ac-
cepted, or seriously studied, till the beginning of the
1 The above translation of the Pope's Latin verse on Photography
Is by my friend, Mr. F. T. Mott, of Leicester.
Expreeaa soils apicnlo O mira virtus ingeni,
Nitene Imago, quaaa bene Novnmque monstrum ! Imaginem
Frontls decrw, vim lumlnum, Natures Apelles amralna
Refers, et oris gratiam. Ron pnlcbriorem pingeret.
3*
33 THE WONDERFUL CENTURY. CHAP. v.
present century, when it was revived by Thomas Young,
and was shown by himself, by Fresnel, and other mathe-
maticians, to explain all the phenomena of refraction,
double-refraction, polarization, diffraction, and interfer-
ence, some of which were inexplicable on the Newtonian
theory of the emission of material particles, which had
previously been almost universally accepted. The com-
plete establishment of the undulatory theory of light is
a fact of the highest importance, and will take a very
high place among the purely scientific discoveries of the
century.
From a more practical point of view, however, noth-
ing can surpass in interest and importance the discovery
and continuous improvement of the Photographic art,
which has now reached such a development that there
is hardly any science or any branch of intellectual study
that is not indebted to it. A brief sketch of its origin
and progress will therefore not be uninteresting.
The fact that certain salts of silver were darkened by
exposure to sunlight was known to the alchemists in the
sixteenth century, and this observation forms the rudi-
ment from which the whole art has been developed.
The application of this fact to the production of pictures
belongs, however, wholly to our own time. In the year
1802, Wedgewood described a mode of copying paint-
ings on glass by exposure to light, but neither he nor Sir
Humphrey Davy could find any means of rendering the
copies permanent. This was first effected in 1814 by
M. IsTiepce of Chalons, but no important results were ob-
tained till 1839, when Daguerre perfected the beautiful
process known as the Daguerrotype. Permanent per-
traits were taken by him on silvered plates, and they were
NEW APPLICATIONS OF LIGHT. 33
so delicate and beautiful that probably nothing in mod-
ern photography can surpass them. For several years
they were the only portraits taken by the agency of
light, but they were very costly, and were therefore com-
pletely superseded when cheaper methods were dis-
covered.
About the same time a method was found for photo-
graphing leaves, lace, and other semi-transparent objects
on paper, and rendering them permanent, but this was of
comparatively little value. In the year 1850, the far
superior collodion-film on glass was perfected, and nega-
tives were taken in a camera-obscura, which, when
placed on black velvet, or when coated with a black com-
position, produced pictures almost as perfect and beauti-
ful as the dagueiTOtype itself, and at much less cost.
Soon afterward positives were printed from the trans-
parent negatives on suitably pr'epared paper, and thus
was initiated the process, which, with endless modifica-
tions and improvements, is still in use. The main ad-
vance has been in the increased sensitiveness of the
photographic plates, so that, first, moving crowds, then
breaking waves, running horses, and other quickly mov>
ing objects were taken, while now a bullet fired from a
rifle can. be photographed in the air.
With such marvellous powers, photography has come
to the aid of the arts and sciences in ways which would
have been perfectly inconceivable to our most learned
men of a century ago. It furnishes the Meteorologist,
the Physicist, and the Biologist, with self -registering in-
struments of extreme delicacy, and enables them to pre-
serve aoctirate records of the most fleeting natural phe-
By mp# pf successive photographs at skort
34 THE WONDERFUL CENTURY.
intervals of time, we are able to study the motions of the
wings of birds, and thus learn something of tlie mechan-
ism of flight; while even the instantaneous lightning-
flash can be depicted, and we thus learn, for the first
time, the exact nature of its path.
Perhaps the most marvellous of all its achievements
is in the field of astronomy. Every increase in the size
and power of the telescope has revealed to us ever more
and more stars in every part of the heavens; but, by the
aid of photography, stars are shown which no telescope
that has been, or that probably ever will be constructed,
can render visible to the human eye. Tor by exposing
the photographic plate in the focus of the object glass
for some hours, almost infinitely faint stars impress their
image, and the modern photographic star-maps show us
a surface densely packed with white points that seem
almost as countless as the sands of the seashore. Tet
every one of these points represents a star in its true
relative position to the visible stars nearest to it, and thus
gives at one operation an amount of accurate detail
which could hardly be equalled by the labor of an
astronomer for months or years even if he could ren-
der all these stars visible, which, as we have seen, ho
cannot do. A photographic survey of the heavens is
now in progress on one uniform system, which, when
completed, will form a standard for future astronomers,
and thus give to our successors some definite knowledge
of the structure, and, perhaps, of the extent of the 'stellar
universe.
Within the last few years the mechanical processes by
means of which photographs can now be reproduced
through the printing press have been rendered so pert
CHAP.V. NEW APPLICATIONS OF LIGHT. 35
feet that books and periodicals are illustrated with an
amount of accuracy and beauty that would have been
impossible, even twenty years ago, except at a prohib-
itive cost.
It has long been the dream of photographers to dis-
cover some mode of obtaining pictures which shall repro-
duce all the colors of nature without the intervention of
the artist's manipulation. This was seen to be exceed-
ingly difficult, if not impossible, because the chemical
action of colored light has no power to produce pigments
of the same color as the light itself, without which a
photograph in natural colors would seem to be impos-
sible. Nevertheless, the problem has been solved, but
in a totally different manner j that is, by the principle of
" interference," instead of by that of chemical action.
This principle was discovered by Newton, and is exem-
plified in the colors of the soap bubble, and in those of
mother-of-pearl and other iridescent objects. It de-
pends on the fact that the differently colored rays are of
different wave-lengths, and the waves reflected from two
surfaces half a wave-length apart neutralize each other
and leave the remainder of the light colored. If, there-
fore, each differently colored ray of light can be made to
produce a corresponding minute wave-structure in a
photographic film, then each part of the film will reflect
only light of that particular wave-length, and therefore
of that particular color, that produced it. This has actu-
ally been done by Professor Lippmann, of Paris, who
published his method in 1891 ; and in a lecture before
the Royal Society in April, 1896, he fully described it
and exhibited many beautiful specimens, 1
i( lfoislec*ure is repbrtedm tfaturt, vol. HU. p. 617.
THE WOKDEEFUL CENTTJftY.
The method is as follows: A sensitive film, of some of
the usual salts of silver in albumin or gelatin, is used,
but with much less silver than usual, so as to leave the
film quite transparent. It must also be perfectly homo-
geneous, since any granular structure would interfere
with the result. This film on glass must be placed in a
frame so constructed that at the back of it there is a
shallow cell that can be filled with mercury which is in
contact with the film. It is then exposed in the usual
way, but much longer than for an ordinary photograph,
so that the light-waves have time to produce the required
effect. The light of each particular tint, being reflected
by the mercury, meets the incoming light and produces
a set of standing waves that is, of waves surging up
and down, each in a fixed plane. The result is that the
metallic particles in the film become assorted and strati-
fied by this continued wave-action, the distance apart of
the strata being determined by the wave-length of the
particular colored light for the violet rays about eight
millionths of an inch; so that in a film of ordinary thick-
ness there would be about five hundred of thcso strata
of thinly scattered metallic particles. The quantity of
silver used being very small, when the film is developed
and fixed in the usual way the result is not a light-and-
shade negative, but a nearly transparent film which
nevertheless reflects a sufficient amount of Jight to pro-
duce a naturally colored picture.
The principle is the same for the light-waves as that
of the telephone for sound-waves. The voice sets up
vibrations in the transmitting diaphragm, which, by
means of an electric current, are so exactly reprpdtice4
in the receiving diaphragm as to give out the same
NEW APPLICATIONS OF LIGHT. 3?
cession of sounds. An even more striking and, perhaps,
closer analogy is that of the phonograph, where the vi-
brations of the diaphragm are permanently registered
on a wax cylinder, which, at any future time, can be
made to set up the same vibrations of the air, and thus
reproduce the same succession of sounds, whether words
or musical notes. So, the rays of every color and tint
that fall upon the plate throw the deposited silver within
the film into minute strata which permanently reflect
light of the very same wave-length, and therefore of the
very same color as that which produced them.
The effects are said to be most beautiful, the only
fault being that the colors are more brilliant than in
nature, just as they are when viewed in the camera itself.
This, however, may perhaps be remedied (if it requires
remedying) by the use of a slightly opaque varnish.
The comparatively little attention that has been given
to this beautiful and scientifically-perfect process, is no
doubt due to the fact that it is rather expensive, and that
the pictures cannot, at present, be nrnltiplied rapidly.
But for that very reason it ought to be especially attract-
ive to amateurs, who would have the pleasure of obtain-
ing exquisite pictures which will not become common-
place by indefinite reproduction.
The brief sketch of the rise and progress of pho-
tography now given illustrates the same fact which we
have already dwelt upon in the case of other discoveries.
This beautiful and wonderful art, which already pkys
an important part in the daily life and enjoyment of all
civilized people, and which has extended the bounds of
human knowledge into the remotest depths of the starry
i& $w>t &a improvement of ? or development
from, anything that went before it, but is a totally new
departure. From that early period when the men of the
stone age rudely outlined the mammoth and the reindeer
on stone or ivory, the only means of representing men
and animals, natural scenery, or the great events of hu-
man history, had been through the art of the painter or
the sculptor. It is true that the highest Greek, or Me-
diaeval, or Modern art, cannot be equalled by the produc-
tions of the photographic camera; but great artists are
few and far between, and the ordinary, or even the
talented draughtsman can give us only suggestions of
what he sees, so modified by his peculiar mannerism as
often to result in a mere caricature of the truth. Should
some historian in Japan study the characteristics of
English ladies at two not remote epochs, as represented,
sa 7> by Frith and by Du Maurier, he would be driven
to the conclusion that there had been a complete change
of type, due to the introduction of some foreign race, in
the interval between the works of these two artists.
From such errors as this we shall be saved by photog-
raphy; and our descendants in the middle of the coming
century will be able to see how much, and what kind, of
change really does occur from age to age.
The importance of this is well seen by comparing any
of the early works on Ethnology, illustrated by por-
traits intended to represent the different " types of man-
kind," with recent volumes which give us copies of
actual photographs of the same types; when we shall see
how untrue to nature are the former, due probably to
the artist having delineated those extreme forms, either
of ugliness or of beauty, that most attracted Ms attest
tion, and to his having exaggerated even these,
CHAP. V.
NEW APPLICATIONS OF LIGHT.
only can we account for tlie pictures in some old voyages,
showing an English sailor and a Patagonian as a dwarf
beside a giant; and for the statement by the historian of
Magellan's voyage, that their tallest sailor only came up
to the waist of the first man they met. It is now known
that the average height of Patagonian men is about five
feet ten inches, or five feet eleven inches, and none have
been found to exceed six feet four inches. Photography
would have saved us from such an error as this.
There will always be work for good artists, especially
in the domain of color and of historical design; but the
humblest photographer is now able to preserve for us,
and for future generations, minutely accurate records of
scenes in distant lands, of the ruins of ancient temples
which are sometimes the only record of vanished races,
and of animals or plants that are rapidly disappearing
through the agency of man. And, what is still more im-
portant, they can preserve for us the forms and faces
of the many lower races whict are slowly but surely
dying out before the rude incursions of our imperfect
civilization.
That such a new and important art as photography
should have had its birth, and have come to maturity, so
closely coincident with the other great discoveries of the
century already alluded to, is surely a very marvellous
fact, and one which will seem more extraordinary to the
future historian than it does to ourselves, who have wit-
nessed the whole process of its growth and development.
The most recent of all the discoveries in connection
with light and photography, and one which extends our
powers of vision in a direction and to an extent the limits
e guessed at, is that peculiar form
40 THE WONDERFUL CENTURY. ciur. v.
of radiation termed the X, or Rontgen Eays, from Pro-
fessor Rontgen of Wiirzburg, who was the first to in-
vestigate their properties and make practical applications
of them. These rays are produced by a special form of
electrical current sent through a vacuum tube, in or
around which is some fluorescent substance, which under
the action of the current become intensely luminous. But
this luminosity has totally different properties from ordi-
nary light, inasmuch as the substances which are opaque
or transparent to it are not the same as those to which wo
usually apply the terms, but often the very contrary.
Paper, for instance, is so transparent that the rays will
pass through a book of a thousand pages, or through
two packs of cards, both of which would be absolutely
opaque to the most brilliant ordinary light. Alumin-
ium, tin, and glass of the same thickness are all trans-
parent, biit they keep out a portion of the rays ; whereas
platinum and lead are quite opaque. To these rays
aluminium is two hundred times as transparent as plati-
num. Wood, carbon, leather, and slate are much more
transparent to the X-Rays than is glass; some kinds of
glass being almost opaque, though quite transparent to
ordinary light. Flesh and skin are transparent in
moderate thicknesses, while bone is opaque. Iloncc, if
the rays are passed through the hand the bones cast a
shadow, though an invisible one; and as, most fortu-
nately, the rays act upon photographic plates almost like
ordinary light, hands or other parts of the body can bo
photographed by their shadows, and will show the bones
by a much darker tint. Hence their use in surgery, to
detect the exact position of bullets or other objects em-
bedded in the flesh or bone. A needle which pene-
. NEW APPLICATION'S OF LIGHT. 41
trated the knee joint and then broke off, leaving a por-
tion embedded which set up inflammation, and might
have necessitated the loss of the limb, was shown so accu-
rately that a surgeon cut down to it and got it out with-
out difficulty,
An exceptional property of these rays is that they
cannot be either refracted or reflected as can ordinary
light and heat. Hence it is only the shadow that can be
photographed. And another curious result of this is
that they can pass through a powder as easily as through
a solid; whereas ordinary light cannot pass through
powdered glass or ice, owing to the innumerable reflec-
tions and refractions which soon absorb all the rays ex-
cept those reflected from a very thin surface layer.
Proportionate thicknesses of aluminium or zinc, whether
in the solid plate or in powder, are equally transparent to
these singular rays.
So much is already popularly known on this subject
that it is not necessary to go into further details here.
But this new form of radiant energy opens up so many
possibilities, both as to its own nature and as to the
illimitable field of research into the properties and
powers of the mysterious ether, that it forms a fitting and
dramatic climax to the scientific discoveries of the
century.
CHAPTER VI.
NEW APPLICATIONS OF LIGHT SPECTRUM ANALYSIS,
Far beyond Orion bright
Cloud on cloud the star-haze lies ;
Million years bear down the light
Earthward from those ghost-like eyes*
F. T. Palgraw.
Hushed be all earthly rhymes !
List to those spheral chimes
That echo down the singing vaults of night.
The quivering impulse runs
From the exultant suns,
Circling in endless harmonies of light.
P. T. Mott.
AMONG the numerous scientific discoveries of our cen-
tury we must give a very high, perhaps even the highest,
place to Spectrum Analysis. !N~ot only because it has
completely solved the problem of the true nature and
cause of the various spectra produced by different kinds
of light, but because it has given us a perfectly new
engine of research, by which we are enabled to penetrate
into the remotest depths of space, and learn something of
the constitution and the motions of the constituent
bodies of the stellar universe. Through its means we
have acquired what are really the equivalents of new
senses, which give us knowledge that before seemed ab-
solutely and forever unattainable by man.
The solar spectrum is that colored band produced by
allowing a sunbeam to pass through a prism, and a por-
tion of it is given by the dewdrop or the crystal when
4$
NEW APPLICATIONS OF LIGHT.
the sun shines upon them; while the complete band is
produced by the numerous raindrops, the colored rays
from which form the rainbow. Newton examined the
colors of the spectrum very carefully, and explained
them on the theory that light of different colors has dif-
ferent ref Tangibilities or, as we now say, different wave-
lengths. He also showed that a similar set of colors can
be produced by the interference of rays when reflected
from the two surfaces of very thin plates, as in the case
of what are termed Newton's rings and in the iridescent
colors of thin films of oil on water, of soap bubbles, and
many other substances.
These color-phenomena, although very interesting in
themselves, and giving us more correct ideas of the
nature of color in the objects around us, did not lead to
anything further. But in 1802, the celebrated chemist,
Dr. "Wollaston, made the remarkable discovery that the
solar-spectrum, when closely examined, is crossed by
very numerous black lines of various thicknesses, and at
irregular distances from each other. Later, in 1817,
these lines were carefully measured and mapped by
Fraunhofer; but their meaning remained an unsolved
problem till about the year 1860, when the German
physicist, Kirchhoff, discovered the secret, and opened up
to 'chemists and astronomers a new engine of research
whose powers are probably not yet exhausted.
It was already known that the various chemical ele-
ments, when heated to incandescence, produce spectra
consisting of a group of colored bands, and it had been
noticed that some of these bands, as the yellow band of
Sodium, corresponded in position with certain black
lines in the solar spectrum. KirchhofPa discovery con-
44 THE WONDERFUL CENTURY. CHIP. vi.
sisted in showing that, when the light from an incandes-
cent body passes through the same substance in a state
of vapor, much of it is absorbed, and the colored bands
become replaced by black lines. The black lines in the
solar spectrum are due, on this theory, to the light from
the incandescent body of the sun being partially ab-
sorbed in passing through the vapors which surround it.
This theory led to a careful examination of the spectra
of all the known elements, and on comparing them with
the solar spectrum it was found that in many cases the
colored bands of the elements corresponded exactly in
position with certain groups of black lines in the solar
spectrum. Thus hydrogen, sodium, iron, magnesium,
copper, zinc, calcium, and many other elements have
been proved to exist in the sun. Some outstanding
solar lines, which did not correspond to any known ter-
restrial element, were supposed to indicate an clement
peculiar to the sun, which was therefore named Helium.
Quite recently this element has been discovered in a rare
mineral, and its colored spectrum is found to correspond
exactly to the dark lines in the solar spectrum on which
it was founded, thus adding a final proof of the correct-
ness of the theory, and affording a striking example of
its value as an instrument of research.
The immediate effect of the application of the spectro-
scope to the stars was very striking. The supposition
that they were suns became a certainty, since they gave
spectra similar in character and often very closely re-
sembling in detail that of our sun. Aldcbaran is one
of the most sun-like stars, being yellow in color and pos-
sessing lines which indicate most of the elements found
iix the sun, "White stars ; such as Sirius and Vega, show
CHAP. vi. NEW APPLICATIONS OF LIGHT. 45
hydrogen lines only; and these are supposed to be hotter
than our sun, and in an earlier stage of development,
while red stars are supposed to be cooling. Other ex-
planations of these facts have, however, been suggested.
Much information has also been obtained as to the
nature of the nebulae. Sir William Herschel supposed
that they were all really star-clusters, but so enormously
remote that even the most powerful telescopes could not
render visible the stars composing them. Later observa-
tions have shown that many of them do consist of stars,
or star-dust, as it has been called; and this seemed to sup-
port the theory that all were so composed, including the
milky way. A study of the distribution of stars and
nebulae by Proctor and others led, however, to the con-
clusion that they were often really connected, and that
nebulae were not, on the average, more distant than stars;
and this view has been confirmed by the spectroscope,
which has shown them often to consist of glowing gas;
and this is especially the characteristic of all those situ-
ated in or near the milky way. The first great result of
spectrum-analysis has thus been to demonstrate the real
nature of many stars and nebulae, to determine some of
the elements of which they are formed, and to give us
some indications of the changes they have undergone,
and thus help us toward a general theory of the develop-
ment of the stellar universe.
Marvellous as is this extension of our knowledge of
objects so distant that our largest telescopes axe power-
less to show them as more than points of light, it is only
a part, perhaps only a small part, of what the spectro-
scope has already done, or may yet do, for astronomy.
By a most r^ftaed series of observations it Tom enabled us
46 THE WONDERFUL CENTURY. OHAP.VI.
to detect and measure certain motions of the stars which,
seemed to be wholly beyond our grasp, and also to
demonstrate the existence of celestial bodies which could
be detected in no other way.
In order to understand how this is possible we have
to make use of the wave-theory of light; and the analogy
of other wave-motions will enable us better to grasp the
principle on which these calculations depend. If on a
nearly calm day we count the waves that pass each min-
ute by an anchored steamboat, and then travel in the
direction the waves come from, we shall find that a larger
number pass us in the same time. Again, if we are
standing near a railway, and an engine comes toward us
whistling, we shall notice that it changes its tone as it
passes us; and as it recedes the sound will be very differ-
ent, although the engine is at the same distance from us
as when it was approaching. Yet the sound does not
change to the ear of the engine-driver, the cause of the
change being that the sound-waves reach us in quicker
succession as the source of the waves is approaching us
than when it is retreating from us. Now just as the
pitch of a note depends upon the rapidity with which the
air-vibrations reach our ear, so does the color of a par-
ticular part of the spectrum depend upon the rapidity
with which the ethereal waves which produce color reach
our eyes; and as this rapidity is greater when the source
of the light is approaching than when it is receding from
us, a slight shifting of the position of the dark lines will
occur, as compared with their position in the spectrum of
the sun or of any stationary source of light, if there is
any motion sufficient in amount to produce a perceptible
shift On experimenting with a powerful spectroscope
CHAP. vi. NEW APPLICATIONS OF LIGHT. 47
constructed for the purpose, Sir William Huggins, in
1868, found that such a change did occur in the case of
many stars, and that their rate of motion toward us or
away from us termed the radial motion could be cal-
culated. As the actual distance of some of these stars
has been measured, and their change of position annually
(their proper motion) determined, the additional factor
of the amount of motion in the direction of our line of
sight completes the data required to fix their true line
of motion among the other stars.
This method of research has now been applied to
many double stars with great success, observations of
their spectra showing that in some cases they move one
toward and one away from us, as they must do if they
are revolving around their common centre of gravity in
an ellipse whose plane lies approximately in our direc-
tion. It has also brought to light the interesting fact
that some stars which appear singly in the most power-
ful telescopes are really double, since their spectra show
a shifting of spectrum lines, which after a considerable
time changes to an opposite direction, and by the period
occupied in the complete change of direction the time of
rotation of the component stars can be determined,
although one of the components has never been seen.
By this means the variable star Algol has been proved to
have a dark companion which partially eclipses it every
69 hours; and both Sirus and Procyon have been shown
to have dark or less visible companions, that of Sinus
being really just visible in the very best telescopes. The
unusual motions of Sirius have been long known, and
were supposed to be due to the presence of a companion,
which has now been shown to be the true explanation.
48 THE WONDEEFUL CENTURY.
Tlie accuracy of tliis metliod under favorable condi-
tions is very great, as has "been proved by those cases in
which we have independent means of calculating the
real motion. The motion of Venus toward or away
from us can be calculated with great accuracy for any
period, being a resultant of the combined motions of the
planet and of our earth in their respective orbits. The
radial motions of Venus were determined at the Lick
Observatory in August and September, 1890, by spoctro-
scopic observations, and also by calculation, to bo as
follows:
BY OBSERVATION", BY CALCULATION.
Aug. 16th. 7.3 miles per second. 8.1 miles per second.
' l 22d. 8.9 " 8.2
" 30th. ' 7.3 " 8.3
Sept. 3d. 8.3 4< 8.3
" 4th. 8.2 " 8.3
showing that the maximum error was only one mile per
second, while the mean error was about a quarter of a
mile. Owing to the greater difficulty in observing the
spectra of stars, the accuracy in their case is probably
not quite so great. This has been tested by observations
of the same star at times when the earth's motion in its
orbit is toward or away from the star, whose apparent
radial velocity is, therefore, increased or diminished by
a known amount. Observations of this kind were made
by Dr. Vogel, Director of "the Astrophysical Observa-
tory at Potsdam, showing, in the case of three stars, of
which ten observations were taken, a mean error of about
two miles per second.
The same observer, from his study of the spectra of
the variable star Algol, has been able tc> determine that
CHAP. vi. NEW APPLICATIONS OF LIGHT. 49
both the visible star and its dark companion are some-
what larger than our sun, though of less density; that
their centers are 3,230,000 miles apart, and that they
move in their orbits at rates of 55 and 26 miles
per second respectively; and this information, it
mast be remembered, has been gained as to objects
the light of which takes about forty-seven years to
reach us!
So striking are these results, and so rapid has been the
increase in the delicacy and trustworthiness of the obser-
vations, that the President of the Eoyal Astronomical
Society, in an address delivered in 1893, contemplated
the possibility that, by still further refinements in the
application of the spectroscope, the most accurate meas-
ures of tlie rate of motion of our earth in its orbit, and,
therefore, of the distance of the sun, might be de-
duced from observations of stars which are them-
selves so remote as to be beyond our powers of
measurement.
So late as the year 1842 the Prench mathematician
and' philosopher, Comte, declared that all study of the
fixed stars was waste of time, because their distance was
so great that we could never learn anything about them
a striking illustration of the complete novelty, no less
than of the wonderful possibilities of this marvellous
engine of research. Not only is it a wholly new depar-
ture from anything known or even imagined before, but
it is able to give us a large and varied amount of knowl-
edge of that portion of the visible universe which has
hitherto been the least known and which seemed to be
the most hopelessly unapproachable. On every ground,
therefore, we must place the discovery and applications
60 THE WONDEBFUL CENTURY.
of Spectrum Analysis as deserving of the Highest place
among the numerous great scientific achievements of the
nineteenth century. 1
1 An admirable popular account of the application of the spectro
scope to the heavens will "be found in an article on "The New-
Astronomy/* in the Nineteenth Century of June, 1897. It is written
by Sir William Huggins, the greater part of whose life has been
deroted to this branch of the science, in which he was one of the
earliest and most successful observers and discoverers.
CHAPTER VH.
THEORETICAL DISCOVERIES IN PHYSICS*
Has matter motion ? Then each atom,
Asserting its perpetual right to dance,
Would make a universe of dust 1
For the world was built in order,
And the atoms march in tune.
Emerson.
THE theoretical discoveries in the domain of physics
(besides those already referred to) have been very nu-
merous, but only a few of them have enough generality
or have become sufficiently popular to require notice in
the present sketch. Two of these discoveries, however,
stand above the general level as important contributions
to our knowledge of the material universe. These are
(1) the determination of the mechanical equivalent of
heat, leading to the general theory of the conservation of
energy, and (2) the molecular theory of gases.
Down to the beginning of this century heat was gen-
erally considered to be a form of matter, termed caloric
or phlogiston. The presence of phlogiston was sup-
posed to render substances combustible, but when the
chemical theory of combustion was discovered by Lavoi-
sier, phlogiston, as the cause of combustion, disappeared,
although caloric, as the material basis of heat, still held
its ground. Close to the end of the last century Count
Rumf ord showed that in boring a brass cannon the heat
developed in 2 hours was sufficient to raise 26J Ibs. of
si
52 THE WONDERFUL CENTURY. OEUP. vit
water from the freezing to tlie boiling point. But, dur-
ing the operation, the metal had lost no weight or under-
gone any other change; and as the production of heat by
this process appeared to be unlimited, he concluded that
heat could not be matter, but merely a kind of motion set
up in the particles of matter by the force exerted.
Bacon and Locke had expressed similar ideas long be-
fore; and, later, Sir Humphrey Davy showed that by
rubbing together two pieces of ice at a temperature be-
low the freezing point sufficient heat was produced to
partially melt them; while other observers found that to
shake water in a bottle raised its temperature, and that
percussion or compression, as had been long known, pro-
duced a considerable amount of heat. These various
facts led to the conclusion that there was a mechanical
equivalent of heat that is, that a certain amount of
force exerted or work done would produce a correspond-
ing amount of heat; and Joule was the first to determine
this accurately by a number of ingenious experiments.
The result was found to be that a pound of water can be
raised 1 0. by an amount of work equal to that required
to raise one pound to the height of 1392 feet, or 1392
Ibs. one foot. Various experiments with different ma-
terials were found always to lead to the same result, and
thus the final blow was given to the material theory of
heat, which was thenceforth held to be a mode.of motion
of the molecules of bodies.
These conclusions led to the more general law of the
conservation of energy, which implies that in any limited
system of bodies, whether a steam-engine or the solar
system, no change can occur in the total amount of tlie
energy it contains unless fresh energy comes to it from
. THEORETICAL DISCOVERIES IN PfiTSICS. 58
without, or is lost by transmission to bodies outside it.
But as, in the case of the sun, some heat is certainly lost
by radiation into space unless an equal amount comes in
from the stellar universe, the system must be cooling,
and in sufficient time would lose all its heat, and there-
fore much of its energy. The chief use of the principle
is to teach us what becomes of force expended without
any apparent result, as when a ball falls to the ground
and conies to rest. "We now know that the energy of
the falling ball is converted into heat, which, if it could
be all preserved and utilized, would again raise the ball
to the height from which it f elL It also enables us to
trace most of the energy around us, whether of wind, or
water, or of living animals, to the heat and light of the
sun. Wind is caused by inequalities of the sun's heat
on the earth; all water power is due to evaporation by
the sun's heat, which thus transfers the water from the
ocean surface to the mountains, producing rivers; solar
heat alone gives power to plants to absorb carbonic acid
and build up their tissues, and the energy thus locked up
is again liberated during the muscular action of the ani-
mals which have fed directly or indirectly on the plants.
This great principle enables us to realize the absolute
interdependence of all the forces of nature. It teaches
us that there is no origination of force upon the earth, but
that all energy either now comes to us from the sun or
was originated in the sun before our earth separated from
it; and we are thus led to the conclusion, that all work,
all motion, every manifestation of power we see around
us, are alike the effects of heat or of other radiant forces
allied to it. This conclusion we shall find is still further
enforced by the next great discovery we liave to notice*
54 THE WONDERFUL CENTUKY.
The molecular theory of gases.
The very remarkable properties of gases, their ap-
parently unlimited elasticity and indefinite powers of
expansion, were very difficult to explain on any -theory
of their molecules being subject to such attractive and
repulsive forces as seem to exist in other states of matter.
A consideration of these properties, together with the
power of diffusion, by which gases of very different den-
sities form a perfect mixture when in contact, and the
fact that by the application of heat almost all liquids and
many solids can be changed into gases, led to the con-
ception that they owed their peculiar properties to their
molecules being in a state of intensely rapid motion in
all directions. On this theory the 'molecules are very
far apart in proportion to their size, and are continually
coming in contact with each other. Owing to their per-
fect elasticity, they rebound without loss of motion or
energy, and their continual impact against the sides of
the vessel containing them is what gives to gases their
great expansibility. From a study of these various
properties it has been calculated that, at ordinary tem-
peratures, there are some hundreds of trillions of mole-
cules in a cubic inch of gas, and that these collide with,
each other eight thousand millions of times in a second.
The average length of the path between two collisions
of a molecule is less than the two hundred thousandth of
an inch; yet this small length is supposed to be at
least a hundred times as great as the diameter of each
molecule.
From the fact that all gases expand with heat and
contract with cold, it is concluded that the ether-vibra*
CHAP. TO. THEORETICAL DISCOVERIES IN PHYSICS. 55
tions we term heat are the cause of the rapid motions of
the gaseous molecules, and that if heat was entirely ab-
sent the motion would cease, and ordinary cohesive
attraction coming into play, the molecules would fall
together and form a liquid or a solid. As a matter of
fact, by intense cold, combined with pressure, all gases
can be liquefied or solidified; and as, on the other hand,
all the solid elements can be liquefied or vaporized by
the intense heat of the electric furnace, we conclude that
all matter when entirely deprived of heat is solid, and
with sufficient heat becomes gaseous.
As might be expected from these varied phenomena,
it has been found that there is no such sharp line of dis-
tinction between the various states of matter as is popu-
larly supposed; some of the properties which are charac-
teristic of matter in one state being present in a less
degree in other states. Viscous bodies, for example,
often present phenomena characteristic of both solids
and fluids. Sealing-wax, pitch, and ice are all brittle at
low temperatures, resembling in this respect such solids
as glass and stone; but they are at the very same time
fluid, if time enough is allowed to exhibit the phe-
nomenon. This is seen in the motion of glaciers, which
move in every respect like true fluids, even to the middle
of the stream flowing quicker than the sides and the top
than the bottom. Eddies and whirls occur in glaciers
as in rivers, and also upward and downward motion, so
that rocks torn off the glacier floor may be carried up-
ward and deposited on surfaces hundreds of feet above
their place of origin. These properties can be shown
to exist by experiment even on a small scale. A slab of
ice, supported
