[Illustration]
DESCRIPTIVE
ZOOPRAXOGRAPHY
OR THE SCIENCE OF ANIMAL LOCOMOTION
MADE POPULAR
BY
EADWEARD MUYBRIDGE
WITH SELECTED OUTLINE TRACINGS REDUCED FROM SOME OF
THE ILLUSTRATIONS OF
"ANIMAL LOCOMOTION"
AN ELECTRO-PHOTOGRAPHIC INVESTIGATION OF CONSECUTIVE
PHASES OF ANIMAL MOVEMENTS, COMMENCED 1872,
COMPLETED 1885, AND PUBLISHED 1887,
UNDER THE AUSPICES OF THE
UNIVERSITY OF PENNSYLVANIA
* * * * *
PUBLISHED AS A MEMENTO OF A SERIES OF LECTURES GIVEN BY THE AUTHOR
UNDER THE AUSPICES OF THE UNITED STATES
GOVERNMENT
BUREAU OF EDUCATION
AT THE
WORLD'S COLUMBIAN EXPOSITION, IN ZOOPRAXOGRAPHICAL HALL
1893
* * * * *
UNIVERSITY OF PENNSYLVANIA
1893
* * * * *
COPYRIGHTED, 1893,
BY
EADWEARD MUYBRIDGE
The Lakeside Press
R. R. DONNELLEY & SONS CO., CHICAGO
* * * * *
SOME OF THE SUBSCRIBERS
TO
"ANIMAL LOCOMOTION."
THE ORIGINAL AUTOGRAPHS ARE ON THE SUBSCRIPTION BOOK
IN THE POSSESSION OF THE AUTHOR.
[Illustration]
* * * * *
[Illustration]
PREFACE.
In the summer of 1892 while the Author was in California, preparing for a
Lecturing tour through Australia and India, he received an invitation from
the Fine Arts Commission of the World's Columbian Exposition to give a
series of Lectures on ZOOPRAXOGRAPHY in association with the Exposition now
being held in Chicago.
As these Lectures under the more familiar title of "The Science of Animal
Locomotion in Its Relation to Design in Art" had already been given at
nearly all the principal Institutions of Art, Science and Education in
Europe and in the United States, (see appendix A) the Author was induced to
believe that they might be repeated in a popular manner at the Exposition,
with some appreciation of the importance of the facts which his
investigation has revealed, not merely by the student of Nature or of Art,
but by that large and important class of students, known as the general
public.
Under this impression he delayed his far Occidental expedition and returned
to Chicago to find a commodious theater erected for this special purpose on
the grounds of the Exposition, to which the name of Zoöpraxographical Hall
had been given; the Science of Zoöpraxography having had its origin in the
Author's first experiments in 1872. It is not intended in this monograph to
give more than a synopsis of the usual course of Lectures on the subject,
nor to reproduce any of the pictured or sculptured representations which
are necessary for its proper elucidation, but merely to describe the common
methods of limb action adopted by quadrupeds--especially by the horse--in
their various acts of progressive motion, and to illustrate the most
important phases of these movements by tracings from the original
photogravures of the Author's work.
In the presentation of a Lecture on Zoöpraxography the course usually
adopted is to project, much larger than the size of life upon a screen, a
series of the most important phases of some act of animal motion--the
stride of a horse, while galloping for example--which are analytically
described. These successive phases are then combined in the Zoöpraxiscope,
which is set in motion, and a reproduction of the original movements of
life is distinctly visible to the audience.
With this apparatus, horse-races are reproduced with such fidelity that the
individual characteristics of the motion of every animal can readily be
seen; flocks of birds fly across the screen with every movement of their
wings clearly perceptible; two gladiators contend for victory with an
energy which would cause the arena to resound with wild applause, athletes
turn somersaults, and other actions by men, women and children, horses,
dogs, cats and wild animals, such as running, dancing, jumping, trotting
and kicking, are illustrated in the same manner. By this method of analysis
and synthesis the eye is taught how to observe and to distinguish the
differences between a true and a false impression of animal movements. The
Zoöpraxiscopical exhibition is followed by illuminated copies of paintings
and sculptures, demonstrating how the movement has been interpreted by the
Artists of all ages; from the primitive engravers of the cave dwelling
period, to the most eminent painters and sculptors of the present day.
* * * * *
INTRODUCTION.
In the year 1872, while the Author was engaged in his official duties as
Photographer of the United States Government for the Pacific coast, there
arose in the city of San Francisco one of those controversies upon Animal
Locomotion, which has engaged the attention of mankind from the dawn of
symbolical design, to the present era of reformation in the artistic
expression of animal movements.
The subject of this particular dispute was the possibility of a horse
having all of his feet free of contact with the ground at the same instant,
while trotting, even at a high rate of speed, and the disputants were Mr.
Frederick MacCrellish and the Hon. Leland Stanford.
The attention of the Author was directed to this controversy and he
immediately sought the means for its settlement.
At this time the rapid dry plate had not yet been evolved from the
laboratory of the chemist, and the problem before him was to develop a
sufficiently intense and contrasted image upon a wet collodion plate, after
an exposure of so brief a duration that a horse's foot moving with a
velocity of more than a hundred lineal feet in a second of time, should be
photographed practically "sharp."
A few days' experimenting and about a dozen negatives, with a celebrated
fast trotter--"Occident"--as a model, while trotting at the rate of a mile
in two minutes and sixteen seconds, laterally in front of the camera,
decided the argument for once and for all time in favor of those disputants
who held the opinion that a horse while trotting was for a portion of his
stride entirely free from contact with the ground. With a knowledge of the
fact that some horses while trotting will make a stride of twenty feet or
more in length, it is difficult to understand why there should ever have
been any difference of opinion on the subject.
These first experiments of Zoöpraxography were made at Sacramento,
California, in May, 1872. A few impressions were printed from the selected
negative for private distribution, and were commented upon by the "Alta
California," a newspaper published in San Francisco.
Thus far the photographs had been made with a single camera, requiring a
separate trotting for each exposure. The horse being of a dark color and
the background white, the pictures were little better than silhouettes, and
it was difficult to distinguish, except by inference, the right feet from
the left.
Several phases of as many different movements had been photographed, which
the Author endeavored with little success to arrange in consecutive order
for the construction of a complete stride.
It then occurred to him that if a number of cameras were placed in a line,
and exposures effected successively in each, with regulated intervals of
time or of distance, an analysis of one single step or stride could be
obtained which would be of value both to the Scientist and the Artist.
The practical application of this system of photographing required
considerable time for its development, and much experimenting with
chemicals and apparatus.
It being desirable that the horses used as models should be representatives
of their various breeds, and the Author not being the owner of any that
could be fairly classed as such, obtained the coöperation of Mr. Stanford,
who owned a fine stud of horses at his farm at Palo Alto, and there
continued his labors.
The apparatus used at this stage of the investigation was essentially the
same as that subsequently constructed for the University of Pennsylvania,
the arrangement of which will be described further on.
Some of the results of these early experiments which illustrated successive
phases of the action of horses while walking, trotting, galloping, &c.,
were published in 1878, with the title of "The Horse in Motion." Copies of
these photographs were deposited the same year in the Library of Congress
at Washington, and some of them found their way to Berlin, London, Paris,
Vienna, &c., where they were criticized by the journals of the day.
In 1882 the Author visited Europe and at a reception given him by Monsieur
Meissonier was invited by that great painter to exhibit the results of his
labors to his brother Artists who had assembled in his studios for that
purpose. M. Meissonier was the first among Artists to acknowledge the value
to Art design of the Author's researches; and upon this occasion, alluding
to a full knowledge of the details of a subject being necessary for its
truthful and satisfactory translation by the Artist, he declared how much
his own impression of a horse's motion had been changed after a careful
study of its consecutive phases.
It is scarcely necessary to point out, in confirmation of M. Meissonier's
assertions, the modifications in the expression of animal movements now
progressing in the works of the Painter and the Sculptor, or to the fact of
their being the result of studious attention to the science of
Zoöpraxography.
In the same year, during a lecture on "The Science of Animal Locomotion in
Its Relation to Design in Art," given at the Royal Institution (see
_Proceedings_ of the Royal Institution of Great Britain, March 13, 1882),
the author exhibited the results of his experiments at Palo Alto, when he,
with the Zoöpraxiscope and an oxy-hydrogen lantern, projected on the wall a
synthesis of many of the actions he had photographed.
It may not be considered irrelevant if he repeats what he on that occasion
said in his analysis of the quadrupedal walk:--
"So far as the camera has revealed, these successive foot fallings are
invariable, and _are probably common to all quadrupeds_....
"It is also probable that these photographic investigations--which were
executed with wet collodion plates, with exposures not exceeding in some
instances the one five-thousandth part of a second--will dispel many
popular illusions as to the gaits of a horse, and future and more
exhaustive experiments, with the advantages of recent chemical discoveries,
will completely unveil all the visible muscular action of men and animals
even during their most rapid movements....
"The employment of automatic apparatus for the purpose of obtaining a
regulated succession of photographic exposures is too recent for it to be
generally used for scientific experiment or for its advantages to be
properly appreciated. At some future time the philosopher will find it
indispensable for many of his investigations."
The great interest manifested in the results of his preliminary labors
convinced the Author that a comprehensive and systematic investigation with
improved mechanical appliances, and newly-discovered chemical
manipulations, would demonstrate many novel facts, not only interesting to
the casual observer, but of indisputable value to the Artist and to the
Scientist. This investigation and the subsequent publication in the
elaborate manner determined upon, assumed such imposing proportions, and
necessarily demanded so large an expenditure, that all publishers, not
unnaturally, shrank from entering the unexplored field.
In this emergency, through the influence of its Provost, Dr. William
Pepper, the University of Pennsylvania with an enlightened exercise of its
functions as a contributor to human knowledge, instructed the Author to
make, under its auspices, a comprehensive investigation of "Animal
Locomotion" in the broadest significance of the words, (see appendix B) and
some of the Trustees and friends of the University constituted themselves a
committee for the purpose of promoting the execution of the work. These
gentlemen were Dr. William Pepper, Chas. C. Harrison, J. B. Lippincott,
Edw. H. Coates, Samuel Dickson and Thomas Hockley.
The Author acknowledges his obligations to these gentlemen for the interest
they took in his labors; for without their generous assistance the work
would probably never have been completed; the total amount expended--nearly
forty thousand dollars--being entirely beyond his own resources. To Drs. F.
X. Dercum, Geo. F. Barker and Horace Jayne, of the University, the Author
is also indebted for much valuable assistance.
[Illustration: Diagram of the Studio at The University of Pennsylvania, and
Arrangement of the Apparatus for Investigating Animal Locomotion.]
STUDIO, APPARATUS, AND METHOD OF WORKING.
For a proper appreciation of the care taken in the Investigation of Animal
Locomotion at the University of Pennsylvania to ensure accurate record of
the consecutive phases of the various movements, attention to the system
adopted is necessary.
In the diagram, B is the _Lateral_ background; consisting of a shed 37
metres or about 120 feet, long, the front of which is open, and divided by
vertical and horizontal threads into spaces 5 centimetres, or about 2
inches, square, and by broader threads into larger spaces 50 centimetres,
or about 19¾ inches, square.
At C and C, 37 metres, or about 120 feet, apart are "_fixed_" backgrounds,
with vertical threads 5 centimetres, or about two inches, from their
centres, with broader threads 30 centimetres, or about 12 inches, from
their centres.
For some investigations, readily distinguishable in the plates,
"_portable_" backgrounds are used, consisting of frames 3 metres wide by 4
metres high,--about 10 feet by 13 feet 4 inches,--over some of which black
cloth and over others white cloth is stretched, all being divided by
vertical and horizontal lines into square spaces of the same description as
those of the lateral background.
These portable backgrounds are used when photographing birds and horses,
and also wild animals when possible to do so.
L. A lateral battery of 24 automatic electro-photographic cameras, arranged
parallel with the line of progressive motion, and usually placed therefrom
about 15 metres or 49 feet.
Slow movements are usually photographed with lenses of 3 inches diameter
and 15 inches equivalent focus; the centres of the lenses being 15
centimetres, or about 6 inches, apart.
Rapid movements are usually photographed with a _portable_ battery of
cameras and smaller lenses.
The centre, between lenses 6 and 7, is opposite the centre of the track T.
For illustrations comprising both "Laterals" and "Foreshortenings," cameras
1 to 12 only are used.
When "Laterals" alone are required, cameras 13 to 24 are connected with the
system and used in their regular sequence.
R. A portable battery of 12 automatic electro-photographic cameras, the
lenses of which are 1¼ inches diameter and 5 inches equivalent focus; the
lenses are arranged 7½ centimetres, or about 3 inches, from their centres.
When the battery is used vertically, lens 6 is usually on the same
horizontal plane as the lenses of the lateral battery.
In the diagram this battery is arranged _vertically_ for a series of "Rear
Foreshortenings," the points of view being at an angle of 90 degrees from
the lateral battery.
F. A battery of 12 automatic electro-photographic cameras, similar to that
placed at R, arranged horizontally for "Front Foreshortenings," the points
of view averaging an angle of 60 degrees from the lateral battery.
O. The position of the operator; the electric batteries; the chronograph
for recording the intervals of time between each successive exposure; the
motor for completing the successive electric circuits, and other apparatus
connected with the investigation.
T T. The track parallel with the lateral battery and covered with
corrugated rubber flooring.
M. The model, approaching the point number "1" on the track where the
series of photographic illustrations will commence.
An estimate having been made of the interval of time which will be
required, between each photographic exposure, to illustrate the complete
movement, or that portion of the complete movement desired, the apparatus
is adjusted to complete a succession of electric circuits at each required
interval of time, and the motor is set in operation. When the series is to
illustrate _progressive_ motion; upon the arrival of the model at the point
marked "1" on the track, the operator, by pressing a button, completes an
electric circuit, which immediately throws into gearing a portion of the
apparatus hitherto at rest. By means of suitably arranged connections, an
electric current is transmitted to each of the 3 cameras marked "1" in the
various batteries, and an exposure is simultaneously made on each of the
photographic plates, respectively, contained therein. At the end of the
predetermined interval of time, a similar current is transmitted to each of
the cameras marked "2," and another exposure made on each of the 3 next
plates, and so forth until each series of exposures in each of the three
batteries is completed. Assuming the operator to have exercised good
judgment in regulating the speed of the apparatus, and in making the first
electric contact at the proper time, and that the figures 1 to 12 represent
the distance traversed by the model in executing the movement desired, the
first three photographic exposures--that is, one exposure in each
battery--will have been synchronously made when the model was passing the
position marked "1" on the track T; the second three exposures will have
been made when the model was passing the position marked "2," and so on
until twelve successive exposures were simultaneously made in each of the
three batteries. This perfect uniformity of time, speed, and distance,
however, was not always obtained.
When this monograph was commenced it was not intended by the author to give
any more than a general idea of the method adopted for obtaining the
results of his investigation; it has, however, been considered that a few
illustrations and brief description of the apparatus devised and used by
him may not be without interest to other students.
For the use of these illustrations he is indebted to the courtesy of Rev.
Jesse Y. Burk, the Secretary of the University, and to J. B. Lippincott
Company, the publishers of "The Muybridge Work at the University of
Pennsylvania," a book which contains, among other essays upon the subject,
"Materials for a Memoir on Animal Locomotion, by Harrison Allen, M. D.,"
and "A Study of Some Normal and Abnormal Movements, by Francis X. Dercum,
M.D., Ph.D."
Figure 1 is a view of the building containing the lateral battery of
twenty-four photographic cameras, all of which were used when as many
consecutive phases of an act of motion were required.
[Illustration: Fig. 1.]
Immediately in front of each of these cameras, and detached therefrom, was
placed an electro-photographic exposor, a side section of which is
represented by Figure 2, in which A is a continuous band of thin rubber
cloth impervious to light; the edges of which are bound with strong tape,
and arranged to run in a groove, and over two rollers RR which are attached
to a frame.
In this endless band are two apertures OO of suitable size, and so arranged
that their full openings as they pass each other shall simultaneously take
place in front of the center of the lens L.
The upper and lower edges of these apertures are kept taut by light steel
rods attached to the tape binding.
To the lower rod of the front aperture is fastened a ring C and a cleat, to
which some elastic rubber bands B are attached; these bands are easily
removable and their number increased at discretion; in some instances of
rapid exposures a tension of twenty-five pounds or more was required. On a
shelf of the frame is a magnet M, over the top of which is arranged a steel
lever G pivoted near the end D which terminates with a slightly indented
projection.
[Illustration: Fig. 2.]
The armature of the magnet is pivoted at H; its upper arm terminates with a
shoulder I. S is a spring to prevent the accidental shifting of the
shoulder from its contact with the lever when the exposor is ready for its
function. N is a set screw to adjust the distance of the armature from the
magnet. To prepare for a series of photographic exposures--the plates
having been already placed in the cameras--the end of the lever G is placed
under the shoulder I; the endless curtain is revolved until the front
aperture O is raised to its proper position, when the ring C is hooked upon
the projecting point D. A cord attached to the rubber bands B is drawn
around the pulley P, and a ring at its end is slipped over a pin, which
keeps the spring at a proper state of tension. Upon the completion of an
electric circuit the armature is drawn towards the magnet; the end of the
lever is released from its contact with the shoulder; the ring C is
released from the projecting point D; the front of the endless curtain is
drawn rapidly downward; the apertures meet in the center of the lens, form
a gradually expanding and then contracting diaphragm, and the exposure is
made. A front view of three electro-photographic exposors is seen in Figure
3. The first of these represents the exposor set and ready for an exposure;
the second shows the meeting of the apertures at the commencement of an
exposure; the third, their position near the completion of the exposure,
they having in the meanwhile uncovered the lens to their full capacity.
[Illustration: Fig. 3.]
Figure 4 illustrates a portable battery of twelve electro-photographic
exposors; it consists of a rectangular box divided into compartments, open
at the front and rear.
[Illustration: Fig. 4.]
In twelve of these compartments are arranged rollers, curtains, magnets,
etc., as previously described, and a compartment through which a focusing
lens is used. The two end compartments provide for the adjustment of the
camera, which is supported in the box to the rear of the exposing
arrangements. A cable of insulated wires for connecting the twelve magnets
with the exposing motor, contains a wire for the return current. As seen in
the engraving, seven of the magnets by the passage of their respective
currents have completed their releasing operations. In the eighth
compartment the two apertures in the exposing band are in the act of
effecting an exposure. The remaining four magnets are awaiting their turn
for action.
Figure 5 is a photographic camera divided into thirteen compartments, each
having a lens of the same construction, and the same focal length; these
are arranged to correspond with the compartments in the electro-exposors.
One of the lenses is provided with a focusing screen, and with it the other
twelve lenses are adjusted to a proper focus without removing the plate
holder behind them from its position in the camera.
The plate holder is constructed to hold three dry plates, each three inches
by twelve inches; the front is divided into twelve compartments, each three
inches square.
[Illustration: Fig. 5.]
Light is excluded from the front by a roller blind, strengthened by thin
narrow slats of hard wood; the blind works in grooves, is drawn over a
concealed roller, and covers the back of the holder when the plates are
being exposed.
Figure 6 is a rear and side view of the circuit maker, conventionally
called the exposing motor.
The motive power is an adjustable weight attached to a cord which is wound
around a drum. Twenty-four binding posts are attached to the table at the
back of the exposing motor; other binding posts are arranged for return or
other currents.
Figure 7 illustrates a front and side view of the upper part of the
exposing motor. Fastened to the frame is a ring of hard rubber, in which
are inserted twenty-four insulated segments of platinum-coated brass; these
segments are connected by insulated wires to the twenty-four binding posts
on the back of the motor table, figure 6.
[Illustration: Fig. 6.]
A shaft, connected by an arrangement of geared wheels to the drum, passes
through the center of the segmented ring and carries a loose collar; a
stout metal rod is firmly attached near its longitudinal center to this
loose collar. One arm of the rod carries a laminated metal scraper, or
contact brush, arranged to travel around the periphery of the ring, and in
its revolution to make contact with each segment in succession. The contact
brush is connected through the arm with one pole of the battery; and each
segment--through its independent wire and magnet of the
electro-exposors--with the other pole.
[Illustration: Fig. 7.]
[Illustration: Fig. 7.]
When twenty-four consecutive phases of an act of motion are to be
photographed from one point of view, all of the insulated segments in the
ring are put in circuit. When twelve consecutive phases are to be
photographed synchronously from each of three points of view, each
alternate segment is placed in circuit with the electric battery.
The manner in which the series of synchronous exposures is effected will be
readily understood by reference to the diagram, 8.
[Illustration: Fig. 8.]
All being in readiness, and the weights and fan wheel adjusted to cause the
contact brush to sweep over the periphery of the ring at the required rate
of speed, the drum, and with it the shaft is set in motion.
At the proper time, pressure on a button completes an independent circuit
through the magnet seen below the segmented ring, figure 7, and in the side
diagram of figure 8.
The action of the armature releases the lower end of the rod on the loose
collar, which, by means of a coiled spring, is immediately thrown into
gearing with the already revolving shaft; the contact brush sweeps around
the segmented ring and effects the consecutive series of exposures at the
pre-arranged intervals of time.
At the University the intervals varied from the one-sixtieth part of a
second to several seconds.
A record of these time intervals was kept by a chronograph, a well known
instrument; it comprises a revolving drum carrying a cylinder of
smoke-blackened paper, on which, by means of successive electric contacts,
a pencil is caused to record the vibrations of a tuning fork, while a
second pencil marks the commencement of each photographic exposure. The
number of vibrations occurring between any two successive exposures marks
the time. The tuning fork used made one hundred single vibrations in a
second of time. To ensure greater minuteness and accuracy in the record,
the vibrations were divided into tenths, and the intervals calculated in
thousandths of a second.
For the purpose of determining the synchronous action of the
electro-exposors while making a double series of exposures, the accuracy of
the time intervals as recorded by the chronograph, and the duration of the
shortest photographic exposures used in the investigation, the two
batteries of portable cameras were placed side by side, and the exposors
were each connected with the exposing motor by separate lengths of a
hundred feet of cable. The two series of cameras were pointed to a rapidly
revolving disc of five feet diameter. The surface of the disc was black,
with narrow white lines radiating from the center to the edge like the
spokes of a wheel. A microscopic examination of the two series of resulting
negatives proved that no variation could be discovered in the synchronous
action of ten of the duplicated series of exposures, and that in the
remaining two a variation existed in the simultaneity of a few
ten-thousandths of a second--a result sufficiently near to simultaneity for
all ordinary photographic work.
[Illustration: Fig. 9.]
A reproduction of the chronographic record of one of these experiments is
seen in figure 9.
The first line records the revolution of the disc; the second the vibration
of the tuning fork; and each group of three long double markings in the
third line indicates a photographic exposure.
The shortest exposures made at the University were--approximately--the one
six-thousandth part of a second; such brief exposures are however for this
class of investigation very rarely needed.
Some horses galloping at full speed will, for a short distance, cover about
fifty-six or fifty-eight feet of ground in a second of time; a full mile
averaging perhaps a hundred seconds. At this speed, a foot recovering its
loss of motion will be thrust forward with an occasional velocity of at
least 120 lineal feet in a second of time.
During the one one-thousandth part of a second the body of the horse will
at this rate move forward about seven one-tenths of an inch, and a moving
foot perhaps one and a half inches, not a very serious matter for the usual
requirements of the amateur photographer.
A knowledge of the duration of the exposures, however, was in this
investigation of no value, and scarcely a matter of curiosity, the aim
always being to give as long an exposure as the rapidity of the action
would permit, with a due regard to the necessary sharpness of outline, and
essential distinctness of detail.
The power used for operating the magnets, through the exposing motor, was
given from a lé Clanché battery of fifty-four cells, arranged in multiple
arc of three series, each of eighteen cells.
During the investigation at the University of Pennsylvania, more than a
hundred thousand photographic exposures were made.
The negative plates were supplied by the Cramer Dry Plate Company of St.
Louis, and the positive plates by the Carbutt Company of Philadelphia. On a
favorable day five hundred or six hundred negatives were sometimes exposed;
on one day the number of exposures reached seven hundred and fifty.
The electrical manipulations were directed by Lino F. Rondinella; the
development room was in charge of Henry Bell. The author takes pleasure in
acknowledging the skill, patience and energy which these gentlemen
exhibited in their respective fields of labor.
Although the one six-thousandth part of a second was the duration of the
most rapid exposure made in this investigation, it is by no means the limit
of mechanically effected photographic exposures, nor does the one-sixtieth
part of a second approach the limit of time intervals. Marey, in his
remarkable physiological investigations, has recently made successive
exposures with far less intervals of time; and the author has devised, and
when a relaxation of the demands upon his time permit, will use an
apparatus which will photograph twenty consecutive phases of a single
vibration of the wing of an insect; even assuming as correct a quotation
from _Nicholson's Journal_ by Pettigrew in his work on Animal Locomotion
that a common house fly will make during flight seven hundred and fifty
vibrations of its wings in a second of time, a number probably far in
excess of the reality.
The ingenious gentlemen who are persistently endeavoring to overcome the
obstacles in the construction of an apparatus for aerial navigation, will
perhaps some day be awakened by the fact that the only successful method of
propulsion will be found in the action of the wing of an insect.
We will now resume the subject proper of this monograph.
It is impossible within its limits to trace the history of the art of
delineating animals in motion, or to illustrate it with examples of the
truthful impressions of the primitive Artists, or of the imaginative and
erroneous conceptions of many of those of modern times. Certain phases of
the facts of Animal Locomotion will alone be treated upon, as demonstrated
by photographic research.
The illustrations and condensed definitions of the various gaits were
prepared by the Author for the "Standard Dictionary." Before studying these
it is essential that the meaning of the terms _step_ and _stride_ should be
distinctly understood.
A STEP is an act of progressive animal motion, in which one of the
supporting members of the body is thrust in the direction of the motion and
the support transferred, wholly, or in part, from one member to another.
A STRIDE is an act of progressive animal motion, which, for its completion,
requires all of the supporting members of the body, in the exercise of
their proper functions, to be consecutively and regularly thrust in the
direction of the movement until they hold the same relative positions in
respect to each other as they did at the commencement of the notation. In
the bipedal walk or run a step is one-half of a stride or full round
movement. With all quadrupeds, except the kangaroo and other jumpers,
_four_ steps are necessary to complete the stride.
THE WALK.
The WALK is a method of progressive motion with a regular individual
succession of limb movements. In the evolution of the terrestrial
vertebrates the walk was probably the first adopted method of locomotion,
and its execution is regulated by the law that the movement of the
_superior_ limb precedes the movement of its lateral _inferior_ limb. This
is proved not merely by the _ordinary_ quadrupedal walk, but by the
suspended motion of the sloth; the crawling of the child upon the ground,
the erect walk of man; and the inverse limb movements of the ape tribe.
The relative time intervals of the foot-fallings vary greatly with many
species of animals, and even with the same animal under different
conditions.
Selecting the horse for the purpose of illustration we find that during the
walk--his slowest progressive movement--he has always two, and for a
varying period of time, or distance, three feet on the ground at once,
while during a very slow walk the support will devolve alternately upon
three feet and upon four feet.
[Illustration: SOME CONSECUTIVE PHASES OF THE WALK.]
If the notation of the foot-fallings commences with the landing of the
right hind foot, the order in which the other feet are placed upon the
ground will be: the right fore, the left hind, and the left fore,
commencing again with the right hind.
Assuming that our observation of the stride of a horse during an ordinary
walk commences with the landing of the right hind foot, the body will then
be supported by both hind and the left fore feet. The left hind is now
lifted, the support of the body devolves upon the diagonals--the right hind
and left fore--and continues so supported until the left hind is in the act
of passing to the front of the right; when the right fore is next placed on
the ground. The left fore is now raised, and the body is supported by the
right laterals, until the landing of the left hind foot relieves its fellow
hind of a portion of its weight. Two steps or one-half of a stride have now
been made, and with the substitution of the right feet for the left, two
other steps will be executed in practically the same manner, and a full
stride will have been completed. We thus see that during the walk a
quadruped is supported by eight different methods, the supporting limbs
being consecutively:
Both hind and left fore.
Right hind and left fore _diagonals_.
Right hind and both fore.
Right hind and right fore _laterals_.
Both hind and right fore.
Left hind and right fore _diagonals_.
Left hind and both fore.
Left hind and left fore _laterals_.
Followed as at the commencement with both hind and left fore.
When, therefore, during a walk, a horse is supported on two legs, with two
feet suspended between them, each pair are laterals. On the other hand,
when the suspended feet are respectively in advance of, and behind the
supporting legs, each pair are diagonals.
These invariable rules have been unknown or ignored by many distinguished
artists of modern times.
THE AMBLE.
The amble is a method of progressive motion with the same sequence of foot
fallings as the walk, but in which a hind foot or a fore foot is lifted
from the ground in advance of its fellow hind foot or its fellow fore foot
being placed thereon. The support of the body therefore devolves
alternately upon a single foot and upon two feet; the single foot being
alternately a hind foot and a fore foot, and the two feet being alternately
laterals and diagonals. At no time is the body entirely unsupported.
The following series of illustrations will clearly demonstrate the
consecutive foot fallings and some characteristic phases of an ambling
stride:
[Illustration: SOME CONSECUTIVE PHASES OF THE AMBLE.]
The amble has various local names, such as the "single foot," the "fox
trot," etc. It has sometimes been erroneously confused with the rack or the
so-called "pace;" it is the most gentle and agreeable to the rider of all
methods of locomotion of the horse, while the rack is the most ungraceful
and disagreeable.
In Scott's romances are many allusions to the "ambling palfry." Ben Jonson
in "Every Man in His Humor" speaks of going "out of the old hackney-pace to
a fine, easy amble," and Dickens in "Barnaby Rudge" refers to "the gray
mare breaking from her sober amble into a gentle trot."
The ambling gait is natural to the elephant, and to the horse, the mule and
the ass; but in many countries these latter animals are not encouraged in
its use.
THE TROT.
The trot is a more or less rapid progressive motion of a quadruped in which
the diagonal limbs act nearly simultaneously in being alternately lifted
from and placed on the ground, and in which the body of the animal is
entirely unsupported twice during each stride.
Selecting for the purpose of illustration the phases occurring during two
steps or one-half of a stride of 18 feet in length by a horse trotting at
the rate of a mile in two minutes and twelve seconds, we find that at the
instant his right fore foot strikes the ground, the left hind foot is a few
inches behind the point where it will presently strike. As the feet
approach the ground, the right hind leg is drawn forward with the pastern
nearly horizontal, while the left fore leg is flexed under the body. After
the feet strike the ground and the legs approach a vertical position the
pasterns are gradually lowered, and act as springs to break the force of
the concussion until they are sometimes bent to a right angle with the
legs.
At this period the fore foot is raised so high as to frequently strike the
elbow, while the diagonal hind foot is comparatively but little above the
ground, and is about to pass to the front of the left hind.
The pasterns gradually rise as the legs pass the vertical until the right
fore foot has left the ground and the last propelling force is being
exercised by the left hind foot; which accomplished, the animal is in mid
air.
The right hind foot continues its onward motion until it is sometimes much
in advance of its lateral fore foot, the former, however, being gradually
lowered, while the latter is being raised. The right hind and both fore
legs are now much flexed, while the left hind is stretched backwards to its
greatest extent with the bottom of the foot turned upwards, the left fore
leg is being thrust forwards and gradually straightened, with the toe
raised as the foot approaches the ground; which accomplished, with a
substitution of the left limbs for the right, we find them in the same
relative positions as when we commenced our examination, and one-half of
the stride is completed.
[Illustration: SOME CONSECUTIVE PHASES OF THE TROT.]
With slight and immaterial differences, such as might be caused by
irregularities of the ground, these movements are repeated by the other
pair of diagonals, and the stride is then complete.
If the stride of a trotting horse is divided into two portions,
representing the comparative distances traversed by the aggregate of the
body while the feet are in contact with, and while they are entirely clear
of, the ground, the relative measurements will be found to vary very
greatly, they being contingent upon length of limb, weight, speed, and
other circumstances.
Heavily built horses will sometimes merely drag the feet just above the
surface, but, in every instance of a trot, the _weight_ of the body is
really unsupported twice during each stride. It sometimes happens that a
fast trotter, during the four steps of a stride, will have all his feet
clear of the ground for a distance exceeding one-half of the length of the
entire stride. Upon landing, a fore foot almost always precedes its
diagonal hind.
It will be observed in the illustrations that while during the fast trot
the fore feet are lifted so high that they frequently strike the breast,
the hind feet are raised but little above the surface of the ground. The
trot is common to all the single-toed and to nearly all the cloven-footed
and soft-footed animals. It has, however, not been recorded as being
adopted by the elephant, the camel, or the giraffe.
THE RACK.
The rack, sometimes miscalled the "pace," is a method of quadrupedal
locomotion in which two lateral feet with nearly synchronous action are
placed upon and lifted from the ground alternately with the other laterals,
the body of the animal being in the intervals entirely without support. The
distance which the propelling feet hurl the animal through the air depends,
as with other movements, upon a variety of circumstances; at a high rate of
speed the distance will be about one-half the total length of the stride.
Upon landing, a hind foot usually precedes its lateral fore.
[Illustration: SOME CONSECUTIVE PHASES OF THE RACK.]
The rack is an ungraceful gait of the horse, and disagreeable to those who
seek comfort in riding.
The movements hitherto described are regular in their action, and a stride
may be divided into two parts, each of which--with a change of limbs--is
practically similar to the other; we now come to methods of progression
which cannot be so divided, and each stride must be considered as a unit of
motion.
THE CANTER.
In the canter we discover the same sequence of foot fallings as in the
walk, but not with the same harmonious intervals of time. The gait
resembles the gallop in respect to its leaving the horse entirely
unsupported for a varying period of time, and in the fact that the spring
into the air is always effected from a fore foot, and the landing upon the
diagonal hind foot; in other respects it materially differs from that
method of progression.
Assuming that during a stride of the canter a horse springs into the air
from a left fore foot, the right hind foot will first reach the ground; the
two fore legs will at this time be flexed under the body, the right being
the first landed, and for a brief period of time the support will devolve
upon the laterals. The right fore foot is rapidly followed by the left
hind. During a very slow canter the other fore foot will sometimes be
landed in advance of the lifting of its diagonal, and the curious phase
presented of all of the feet being in contact with the ground at the same
instant. Usually, however, the first hind foot to touch the ground will be
lifted, and the support thrown upon the diagonals.
The left fore is now brought down, and is followed by the lifting of the
right fore; when the left laterals assume the duty of support. The left
hind is now raised, and with a final thrust of the left fore foot the
animal is projected into the air, to land again upon its diagonal, and
repeat the same sequence of movements.
The above phases are selected from a single complete stride, in which the
landing occurs on the _right_ hind foot. Had the horse sprung from a
_right_ fore foot, the right and left feet would have been reversed through
the entire series.
[Illustration: SOME CONSECUTIVE PHASES OF THE CANTER.]
THE GALLOP.
The gallop is the most rapid method of quadrupedal motion; in its action
the feet are independently brought to the ground; the spring into the air
as in the canter is effected from a fore foot, and the landing upon the
diagonal hind foot.
The phases illustrated are selected from the stride of a thorough-bred
Kentucky horse, galloping at the rate of a mile in a hundred seconds, with
a stride of about twenty-one lineal feet.
The length of stride and the distance which the body is carried forward
without support depend upon many circumstances, such as the breed, build
and condition of the horse, speed, track, etc.
The phases illustrated and the measurement given apply to one stride of one
horse, but may be considered as fairly representing the stride of a
first-class horse in prime racing condition at the height of his speed,
upon a good track.
Assuming--as in this instance--the springing into the air to have been
effected from the right fore foot, the landing will take place in advance
of the centre of gravity, upon the diagonal, or left hind foot; above, will
be suspended the right hind foot, and at a higher elevation, several inches
to the rear, will be the right fore foot, with the sole turned upward. The
left fore leg will be in advance of the right, and also flexed. The force
of the impact and the weight of the horse causes the pastern to form a
right angle with the leg, and the heel is impressed into the ground.
[Illustration: SOME CONSECUTIVE PHASES OF THE GALLOP.]
The right hind foot strikes the ground and shares the weight of the body.
The left hind foot leaves the ground while the right hind pastern is in its
horizontal phase, supporting all the weight. At this period the left fore
leg is perfectly straight, with the toe much higher than the heel, and is
thrust forward until the pastern joint is vertical with the nose, the right
fore knee is bent at a right angle. The left fore foot now strikes and
these diagonals are for a brief period upon the ground together. The left
fore leg, however, immediately assumes the entire responsibility of support
and attains a vertical position, with the pastern at a right angle. The
right fore leg becomes perfectly rigid, and is thrust forward to its
fullest extent. The right fore foot now strikes the ground, the two fore
legs form a right angle, and the hind feet are found thrust backward, the
right to its fullest extent. The left fore leg having completed its
functions of support, is now lifted, and the weight transferred to the
right fore foot alone, which is soon found behind the centre of gravity;
the left hind foot passes to the front of the right fore leg, which,
exercising its final act of propulsion, thrusts the horse through the air;
the left hind foot descends; the stride is completed, and the consecutive
phases are renewed. From this analysis we learn that if the spring is made
from the right fore foot during the rapid gallop of a thoroughbred horse,
it is supported consecutively by
The left hind foot.
Both hind feet.
The right hind foot.
The right hind and the left fore feet.
The left fore foot.
Both fore feet.
The right fore foot.
From which he springs into the air to re-commence the phases with the left
hind foot, while the only phase in which he has been discovered without
support is one when the legs are flexed under the body. All of the feet at
this time are nearly close together and have comparatively little
independent motion; this phase, therefore, more persistently than any
other, forces itself upon the attention of the careful observer, and
conveys to him the impression of a horse's rapid motion in singular
contradiction to the conventional interpretation, until quite recently,
usually adopted by the Artist.
It should not be understood that the term "spring" implies that the body of
the horse is greatly elevated by that action; were it so, much force would
be unnecessarily expended with the result of loss of speed. The center of
gravity of a horse trotting or galloping at a high rate of speed will
preserve an almost strictly horizontal line, the undulations being very
slight.
In the gallop of the horse it is probable there may be sometimes a period
of suspension between the lifting of one fore foot and the descent of the
other, but it has not yet been demonstrated.
The method of galloping described applies to the horse and its allies, and
to most of the cloven and soft-footed animals.
In the gallop of the dog the sequence of foot falling and the action of the
body is materially different, and the animal is free from support twice in
each stride.
[Illustration: THE GALLOP OF THE DOG.]