exposure device. Each negative would have but one-forty-sixth of a
second to itself, and that must include the time during which the
fresh surface of film was being brought into position before the lens.
He therefore introduced an intermittent gearing, which jerked the
film forwards forty-six times per second, but allowed it to remain
stationary for nine-tenths of the period allotted to each picture.
During the time of movement the lens was covered by the shutter. This
principle of exposure has also been largely adopted by other
inventors. By its means weak negatives are avoided, while pictures
projected on to a screen gain greatly in brilliancy and steadiness.
The capabilities of a long flexible film-band having been shown by
Edison, he was not long without imitators. Phantoscopes, Bioscopes,
Photoscopes, and many other instruments followed in quick succession.
In 1895 Messrs. Lumière scored a great success with their
Cinematograph, which they exhibited at Marseilles and Paris; throwing
the living picture as we now know it on to a screen for a large
company to see. This camera-lantern opens the era of commercial
animated-photography. The number of patents taken out since 1895 in
connection with living-picture machines is sufficient proof that
inventors have either found in this particular branch of photography a
peculiar fascination, or have anticipated from it a substantial
profit.
A company known as the Mutoscope and Biograph Company has been formed
for the sole object of working the manufacture and exhibition of the
living picture on a great commercial scale. The present company is
American, but there are subsidiary allied companies in many parts of
the world, including the British Isles, France, Italy, Belgium,
Germany, Austria, India, Australia, South Africa. The part that the
company has played in the development of animated photography will be
easily understood from the short account that follows.
The company controls three machines, the Mutograph, or camera for
making negatives; the Biograph, or lantern for throwing pictures on to
the screen; and the Mutoscope, a familiar apparatus in which the same
pictures may be seen in a different fashion on the payment of a penny.
Externally the Mutograph is remarkable for its size, which makes it a
giant of its kind. The complete apparatus weighs, with its
accumulators, several hundreds of pounds. It takes a very large
picture, as animatograph pictures go--two by two-and-a-half inches,
which, besides giving increased detail, require less severe
magnification than is usual with other films. The camera can make up
to a hundred exposures per second, in which time _twenty-two_ feet of
film will have passed before the lens.
The film is so heavy that were it arrested bodily during each exposure
and then jerked forward again, it might be injured. The mechanism of
the mutograph, driven at regular speed, by an electric motor, has been
so arranged as to halt only that part of the film which is being
exposed, the rest moving forward continuously. The exposed portion,
together with the next surface, which has accumulated in a loop
behind it, is dragged on by two rollers that are in contact with the
film during part only of their revolutions. Thus the jerky motion is
confined to but a few inches of the film, and even at the highest
speeds the camera is peculiarly free from vibration.
An exposed mutograph film is wound for development round a skeleton
reel, three feet in diameter and seven long, which rotates in a
shallow trough containing the developing solution. Development
complete, the reel is lifted from its supports and suspended over a
succession of other troughs for washing, fixing, and final washing.
When dry the negative film is passed through a special printing frame
in contact with another film, which receives the positive image for
the biograph. The difficulty of handling such films will be
appreciated to a certain extent even by those whose experience is
confined to the snaky behaviour of a short Kodak reel during
development.
The Mutoscope Company’s organisation is as perfect as its machinery.
It has representatives in all parts of the world. Wherever stirring
events are taking place, whether in peace or war, a mutograph operator
will soon be on the spot with his heavy apparatus to secure pictures
for world-wide exhibition. It need hardly be said that great
obstacles, human and physical, have often to be overcome before a film
can be exposed; and considerable personal danger encountered. We read
that an operator, despatched to Cuba during the Spanish-American War
was left three days and nights without food or water to guard his
precious instruments, the party that had landed him having suddenly
put to sea on sighting a Spanish cruiser. Another is reported to have
had a narrow escape from being captured at sea by the Spaniards after
a hot chase. It is also on record that a mutograph set up in Atlantic
City to take a procession of fire-engines was charged and shattered by
one of the engines; that the operators were flung into the crowd: and
that nevertheless the box containing the exposed films was uninjured,
and on development yielded a very sensational series of pictures
lasting to the moment of collision.
The Mutoscope Company owns several thousand series of views, none
probably more valuable than those of his Holiness the Pope, who
graciously gave Mr. W. K. Dickson five special sittings, during which
no less than 17,000 negatives were made, each one of great interest to
millions of people throughout the world.
The company spares neither time nor money in its endeavour to supply
the public with what will prove acceptable. A year’s output runs into
a couple of hundred miles of film. As much as 700 feet is sometimes
expended on a single series, which may be worth anything up to £1000.
The energy displayed by the operators is often marvellous. To take
instances. The Derby of 1898 was run at 3.20 P.M. At ten o’clock the
race was run again by Biograph on the great sheet at the Palace
Theatre. On the home-coming of Lord Kitchener from the Soudan
Campaign, a series of photographs was taken at Dover in the afternoon
and exhibited the same evening! Or again, to consider a wider sphere
of action, the Jubilee Procession of 1897 was watched in New York ten
days after the event; two days later in Chicago; and in three more the
films were attracting large audiences in San Francisco, 5000 miles
from the actual scene of the procession!
One may easily weary of a series of single views passed slowly through
a magic-lantern at a lecture or entertainment. But when the Biograph
is flashing its records at lightning speed there is no cause for
dullness. It is impossible to escape from the fascination of
_movement_. A single photograph gives the impression of mere
resemblance to the original; but a series, each reinforcing the
signification of the last, breathes life into the dead image, and
deludes us into the belief that we see, not the representation of a
thing, but the thing itself. The bill of fare provided by the Biograph
Company is varied enough to suit the most fastidious taste. Now it is
the great Naval Review off Spithead, or President Faure shooting
pheasants on his preserves near Paris. A moment’s pause and then the
magnificent Falls of Niagara foam across the sheet; Maxim guns fire
harmlessly; panoramic scenes taken from locomotives running at high
velocity unfold themselves to the delighted spectators, who feel as if
they really were speeding over open country, among towering rocks, or
plunging into the darkness of a tunnel. Here is an express approaching
with all the quiver and fuss of real motion, so faithfully rendered
that it seems as if a catastrophe were imminent; when, snap! we are
transported a hundred miles to watch it glide into a station. The
doors open, passengers step out and shake hands with friends, porters
bustle about after luggage, doors are slammed again, the guard waves
his flag, and the carriages move slowly out of the picture. Then our
attention is switched away to the 10-inch disappearing gun, landing
and firing at Sandy Hook. And next, as though to show that nothing is
beneath the notice of the biograph, we are perhaps introduced to a
family of small pigs feeding from a trough with porcine earnestness
and want of manners.
It must not be thought that the Living Picture caters for mere
entertainment only. It serves some very practical and useful ends. By
its aid the movements of machinery and the human muscles may be
studied in detail, to aid a mechanical or medical education. It
furnishes art schools with all the poses of a living model. Less
serious pursuits, such as dancing, boxing, wrestling and all athletic
sports and exercise, will find a use for it. As an advertising medium
it stands unrivalled, and we shall owe it a deep debt of gratitude if
it ultimately supplants the flaring posters that disfigure our towns
and desecrate our landscapes. Not so long since, the directors of the
Norddeutscher-Lloyd Steamship Company hired the biograph at the
Palace Theatre, London, to demonstrate to anybody who cared to witness
a very interesting exhibition that their line of vessels should always
be used for a journey between England and America.
The Living Picture has even been impressed into the service of the
British Empire to promote emigration to the Colonies. Three years ago
Mr. Freer exhibited at the Imperial Institute and in other places in
England a series of films representing the 1897 harvest in Manitoba.
Would-be emigrants were able to satisfy themselves that the great
Canadian plains were fruitful not only on paper. For could they not
see with their own eyes the stately procession of automatic “binders”
reaping, binding, and delivering sheaves of wheat, and puffing engines
threshing out the grain ready for market? A far preferable method this
to the bogus descriptions of land companies such as lured poor
Chuzzlewit and Mark Tapley into the deadly swamps of “Eden.”
Again, what more calculated to recruit boys for our warships than the
fine Polytechnic exhibition known as “Our Navy”? What words, spoken or
printed, could have the effect of a series of vivid scenes truthfully
rendered, of drills on board ship, the manning and firing of big guns,
the limbering-up of smaller guns, the discharge of torpedoes, the
headlong rush of the “destroyers”?
The Mutoscope, to which reference has been made above, may be found in
most places of public entertainment, in refreshment bars, on piers,
in exhibitions, on promenades. A penny dropped into a slot releases a
handle, the turning of which brings a series of pictures under
inspection. The pictures, enlarged from mutograph films, are mounted
in consecutive order round a cylinder, standing out like the leaves of
a book. When the cylinder is revolved by means of the handle the
picture cards are snapped past the eye, giving an effect similar to
the lifelike projections on a biograph screen. From 900 to 1000
pictures are mounted on a cylinder.
The advantages of the mutoscope--its convenient size, its simplicity,
and the ease with which its contents may be changed to illustrate the
topics and events of the day--have made the animated photograph
extremely popular. It does for vision what the phonograph does for
sound. In a short time we shall doubtless be provided with handy
machines combining the two functions and giving us double value for
our penny.
The real importance and value of animated photography will be more
easily estimated a few years hence than to-day, when it is still more
or less of a novelty. The multiplication of illustrated newspapers and
magazines points to a general desire for pictorial matter to help down
the daily, weekly, or monthly budget of news, even if the
illustrations be imaginative products of Fleet Street rather than
faithful to fact. The reliable living picture (we expect the
“set-scene”) which “holds up a mirror to nature,” will be a companion
rather than a rival of journalism, following hard on the description
in print of an event that has taken place under the eye of the
recording camera. The zest with which we have watched during the last
two years biographic views of the embarkation and disembarkation of
troops, of the transport of big guns through drifts and difficult
country, and of the other circumstances of war, is largely due to the
descriptions we have already read of the things that we see on the
screen. And, on the other hand, the impression left by a series of
animated views will dwell in our memories long after the contents of
the newspaper columns have become confused and jumbled. It is
therefore especially to be hoped that photographic records will be
kept of historic events, such as the Jubilee, the Queen’s Funeral,
King Edward’s Coronation, so that future generations may, by the
turning of a handle, be brought face to face with the great doings of
a bygone age.
THE GREAT PARIS TELESCOPE
A telescope so powerful that it brings the moon apparently to within
thirty-five miles of the earth; so long that many a cricketer could
not throw a ball from one end of it to the other; so heavy that it
would by itself make a respectable load for a goods train; so
expensive that astronomically-inclined millionaires might well
hesitate to order a similar one for their private use.
Such is the huge Paris telescope that in 1900 delighted thousands of
visitors in the French Exposition, where, among the many wonderful
sights to be seen on all sides, it probably attracted more notice than
any other exhibit. This triumph of scientific engineering and dogged
perseverance in the face of great difficulties owes its being to a
suggestion made in 1894 to a group of French astronomers by M.
Deloncle. He proposed to bring astronomy to the front at the coming
Exposition, and to effect this by building a refracting telescope that
in size and power should completely eclipse all existing instruments
and add a new chapter to the “story of the heavens.”
To the mind unversed in astronomy the telescope appeals by the
magnitude of its dimensions, in the same way as do the Forth Bridge,
the Eiffel Tower, the Big Wheel, the statue of Liberty near New York
harbour, the Pyramids, and most human-made “biggest on records.”
At the time of M. Deloncle’s proposal the largest refracting telescope
was the Yerkes’ at William’s Bay, Wisconsin, with an object-glass
forty inches in diameter; and next to it the 36-inch Lick instrument
on Mount Hamilton, California, built by Messrs. Alvan Clark of
Cambridgeport, Massachusetts. Among reflecting telescopes the prior
place is still held by Lord Rosse’s, set up on the lawn of Birr Castle
half a century ago. Its speculum, or mirror, weighing three tons, lies
at the lower end of a tube six feet across and sixty feet long. This
huge reflector, being mounted in meridian, moves only in a vertical
direction. A refracting telescope is one of the ordinary pocket type,
having an object-lens at one end and an eyepiece at the other. A
reflector, on the other hand, has no object-lens, its place being
taken by a mirror that gathers the rays entering the tube and reflects
them back into the eyepiece, which is situated nearer the mouth end of
the tube than the mirror itself.
Each system has its peculiar disadvantages. In reflectors the image is
more or less distorted by “spherical aberration.” In refractors the
image is approximately perfect in shape, but liable to “chromatic
aberration,” a phenomenon especially noticeable in cheap telescopes
and field-glasses, which often show objects fringed with some of the
colours of the spectrum. This defect arises from the different
refrangibility of different light rays. Thus, violet rays come to a
focus at a shorter distance from the lens than red rays, and when one
set is in focus to the eye the other must be out of focus. In
carefully-made and expensive instruments compound lenses are used,
which by the employment of different kinds of glass bring all the
colours to practically the same focus, and so do away with chromatic
aberration.
To reduce colour troubles to a _minimum_ M. Deloncle proposed that the
object-lens should have a focal distance of about two hundred feet,
since a long focus is more easily corrected than a short one, and a
diameter of over fifty-nine inches. The need for so huge a lens arises
out of the optical principles of a refractor. The rays from an
object--a star, for instance--strike the object-glass at the near end,
and are bent by it into a converging beam, till they all meet at the
focus. Behind the focus they again separate, and are caught by the
eyepiece, which reduces them to a parallel beam small enough to enter
the pupil. We thus see that though the unaided eye gathers only the
few rays that fall directly from the object on to the pupil, when
helped by the telescope it receives the concentrated rays falling on
the whole area of the object-glass; and it would be sensible of a
greatly increased brightness had not this light to be redistributed
over the image, which is the object magnified by the eyepiece.
Assuming the aperture of the pupil to be one-tenth of an inch, and
the object to be magnified a hundred times, the object-lens should
have a hundred times the diameter of the pupil to render the image as
bright as the object itself. If the lens be five instead of ten inches
across, a great loss of light results, as in the high powers of a
microscope, and the image loses in distinctness what it gains in size.
As M. Deloncle meant his telescope to beat all records in respect of
magnification, he had no choice but to make a lens that should give
proportionate illumination, and itself be of unprecedented size.
At first M. Deloncle met with considerable opposition and ridicule.
Such a scheme as his was declared to be beyond accomplishment. But in
spite of many prophecies of ultimate failure he set to work,
entrusting the construction of the various portions of his colossal
telescope to well-tried experts. To M. Gautier was given the task of
making all the mechanical parts of the apparatus; to M. Mantois the
casting of the giant lenses; to M. Despret the casting of the huge
mirror, to which reference will be made immediately.
The first difficulty to be encountered arose from the sheer size of
the instrument. It was evidently impossible to mount such a leviathan
in the ordinary way. A tube, 180 feet long, could not be made rigid
enough to move about and yet permit careful observation of the stars.
Even supposing that it were satisfactorily mounted on an “equatorial
foot” like smaller glasses, how could it be protected from wind and
weather? To cover it, a mighty dome, two hundred feet or more in
diameter, would be required; a dome exceeding by over seventy feet the
cupola of St. Peter’s, Rome; and this dome must revolve easily on its
base at a pace of about fifty feet an hour, so that the telescope
might follow the motion of the heavenly bodies.
The constructors therefore decided to abandon any idea of making a
telescope that could be moved about and pointed in any desired
direction. The alternative course open to them was to fix the
telescope itself rigidly in position, and to bring the stars within
its field by means of a mirror mounted on a massive iron frame--the
two together technically called a siderostat. The mirror and its
support would be driven by clockwork at the proper sidereal rate. The
siderostat principle had been employed as early as the eighteenth
century, and perfected in recent years by Léon Foucault, so that in
having recourse to it the builders of the telescope were not
committing themselves to any untried device.
In days when the handling of masses of iron, and the erection of huge
metal constructions have become matters of everyday engineering life,
no peculiar difficulty presented itself in connection with the
metal-work of the telescope. The greatest possible care was of course
observed in every particular. All joints and bearings were adjusted
with an extraordinary accuracy; and all the cylindrical moving parts
of the siderostat verified till they did not vary from perfect
cylindricity by so much as one twenty-five-thousandth of an inch!
The tube of the telescope, 180 feet long, consisted of twenty-four
sections, fifty-nine inches in diameter, bolted together and supported
on seven massive iron pillars. It weighed twenty-one tons. The
siderostat, twenty-seven feet high, and as many in length, weighed
forty-five tons. The lower portion, which was fixed firmly on a bed of
concrete, had on the top a tank filled with quicksilver, in which the
mirror and its frame floated. The quicksilver supported nine-tenths of
the weight, the rest being taken by the levers used to move the
mirror. Though the total weight of the mirror and frame was thirteen
tons, the quicksilver offered so little resistance that a pull of a
few pounds sufficed to rotate the entire mass.
The real romance of the construction of this huge telescope centres on
the making of the lenses and mirror. First-class lenses for all
photographic and optical purposes command a very high price on account
of the care and labour that has to be expended on their production;
the value of the glass being trifling by comparison. Few, if any,
trades require greater mechanical skill than that of lensmaking; the
larger the lens the greater the difficulties it presents, first in the
casting, then in the grinding, last of all in the polishing. The
presence of a single air-bubble in the molten glass, the slightest
irregularity of surface in the polishing may utterly destroy the
value of a lens otherwise worth several thousands of pounds.
[Illustration: _Reproduced by the permission of Proprietors of
“Knowledge.”_
_General view, of the Great Paris Telescope, showing the eye-end. The
tube is 180 feet long, and 59 inches in diameter. It weighs 21 tons._]
The object-glass of the great telescope was cast by M. Mantois, famous
as the manufacturer of large lenses. The glass used was boiled and
reboiled many times to get rid of all bubbles. Then it was run into a
mould and allowed to cool very gradually. A whole month elapsed before
the breaking of a mould, when the lens often proved to be cracked on
the surface, owing to the exterior having cooled faster than the
interior and parted company with it. At last, however, a perfect cast
resulted.
M. Despret undertook the even more formidable task of casting the
mirror at his works at Jeumont, North France. A special furnace and
oven, capable of containing over fifteen tons of molten glass, had to
be constructed. The mirror, 6-1/2 feet in diameter and eleven inches
thick, absorbed 3-3/4 tons of liquid glass; and so great was the
difficulty of cooling it gradually, that out of the twenty casts
eighteen were failures.
The rough lenses and mirror having been ground to approximate
correctness in the ordinary way, there arose the question of
polishing, which is generally done by one of the most sensitive and
perfect instruments existing-the human hand. In this case, owing to
the enormous size of the objects to be treated, hand work would not
do. The mere hot touch of a workman would raise on the glass a tiny
protuberance, which would be worn level with the rest of the surface
by the polisher, and on the cooling of the part would leave a
depression, only 1-75,000 of an inch deep, perhaps, but sufficient to
produce distortion, and require that the lens should be ground down
again, and the whole surface polished afresh.
M. Gautier therefore polished by machinery. It proved a very difficult
process altogether, on account of frictional heating, the rise of
temperature in the polishing room, and the presence of dust. To insure
success it was found necessary to warm all the polishing machinery,
and to keep it at a fixed temperature.