toby
/
zotero-db
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
zotero-db/storage/TI7NHRLB/.zotero-ft-cache

667 lines
45 KiB
Plaintext
Raw Normal View History

First ZDB push. Testing repo functionality.
2024-08-12 13:51:37 -05:00
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
The Project Gutenberg eBook of On the relative motion of the earth and the luminiferous æther
This ebook is for the use of anyone anywhere in the United States and most other parts of the world at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this ebook or online at www.gutenberg.org. If you are not located in the United States, you will have to check the laws of the country where you are located before using this eBook.
Title: On the relative motion of the earth and the luminiferous æther
Author: Albert A. Michelson Edward Williams Morley
Release date: May 31, 2023 [eBook #70888]
Language: English
Original publication: UK: Taylor & Francis, 1887
Credits: Laura Natal Rodrigues (Images generously made available by The Internet Archive.)
*** START OF THE PROJECT GUTENBERG EBOOK ON THE RELATIVE MOTION OF THE EARTH AND THE LUMINIFEROUS ÆTHER ***
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
1/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
THE LONDON, EDINBURGH and DUBLIN
PHILOSOPHICAL MAGAZINE AND
JOURNAL OF SCIENCE.
[FIFTH SERIES.]
DECEMBER 1860.
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
2/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
LVIII. On the Relative Motion of the Earth and the Luminiferous Æther.
By ALBERT A. MICHELSON and EDWARD W. MORLEY[1].
T he discovery of the aberration of light was soon followed by an explanation according to the emission theory. The effect was attributed to a simple composition of the velocity of light with the velocity of the earth in its orbit. The difficulties in this apparently sufficient explanation were overlooked until after an explanation on the undulatory theory of light was proposed. This new explanation was at first almost as simple as the former. But it failed to account for the fact proved by experiment that the aberration was unchanged when observations were made with a telescope filled with water. For if the tangent of the angle of aberration is the ratio of the velocity of the earth to the velocity of light, then, since the latter velocity in water is three-fourths its velocity in a vacuum, the aberration observed with a water telescope should be four-thirds of its true value.[2]
On the undulatory theory, according to Fresnel, first, the æther is supposed to be at rest except in the interior of transparent media, in which secondly, it is supposed to move with a
velocity less than the velocity of the medium in the ratio
, where is the index of
refraction. These two hypotheses give a complete and satisfactory explanation of aberration. The second hypothesis, notwithstanding its seeming improbability, must be considered as fully proved, first, by the celebrated experiment of Fizeau,[3] and secondly, by the ample confirmation of our own work.[4]. The experimental trial of the first hypothesis forms the subject of the present paper.
If the earth were a transparent body, it might perhaps be conceded, in view of the experiments just cited, that the inter-molecular æther was at rest in space, notwithstanding the motion of the earth in its orbit; but we have no right to extend the conclusion from these experiments to opaque bodies. But there can hardly be question that the æther can and does pass through metals. Lorentz cites the illustration of a metallic barometer tube. When the tube is inclined the æther in the space above the mercury is certainly forced out, for it is imcompressible.[5]. But again we have no right to assume that it makes its escape with perfect freedom, and if there be any resistance, however slight, we certainly could not assume an opaque body such as the whole earth to offer free passage through its entire mass. But as Lorentz aptly remarks: "Quoi qu'il en soit, on fera bien, à mon avis, de ne pas se laisser guider, dans une question aussi importante, par des considérations sur le degré de probabilité ou de simplicité de l'une ou de l'autre hypothèse, mais de s'addresser a l'expérience pour apprendre à connaitre l'état, de repos ou de mouvement, dans lequel se trouve l'æther à la surface terrestre."[6]
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
3/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
In April, 1881, a method was proposed and carried out for testing the question experimentally.[7]
In deducing the formula for the quantity to be measured, the effect of the motion of the earth through the æther on the path of the ray at right angles to this motion was overlooked. [8] The discussion of this oversight and of the entire experiment forms the subject of a very searching analysis by H. A. Lorentz,[9], who finds that this effect can by no means be disregarded. In consequence, the quantity to be measured had in fact but one-half the value supposed, and as it was already barely beyond the limits of errors of experiment, the conclusion drawn from the result of the experiment might well be questioned; since, however, the main portion of the theory remains unquestioned, it was decided to repeat the experiment with such modifications as would insure a theoretical result much too large to be masked by experimental errors. The theory of the method may be briefly stated as follows: —
Let , fig. 1, be a ray of light which is partly reflected in , and partly transmitted in , being returned by the mirrors and , along and . is partly transmitted along , and is partly reflected along .
Fig. 1.
If then the paths and are equal, the two rays interfere along . Suppose now, the æther being at rest, that the whole apparatus moves in the direction , with the velocity of the earth in its orbit, the directions and distances traversed by the rays will be altered thus: —
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
4/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
Fig. 2.
The ray is reflected along , fig. 2; the angle , being equal to the aberration , is
returned along , (
), and goes to the focus of the telescope, whose direction is
unaltered. The transmitted ray goes along , is returned along , and is reflected at ,
making
equal
, and therefore still coinciding with the first ray. It may be
remarked that the rays and , do not now meet exactly in the same point , though
the difference is of the second order; this does not affect the validity of the reasoning. Let it
now be required to find the difference in the two paths , and .
Let
.
.
, fig. 1.
.
, (fig. 2.)
Then
The whole time of going and coming is
and the distance traveled in this time is
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
5/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
neglecting terms of the fourth order. The length of the other path is evidently
or to the same degree of accuracy,
. The difference is
therefore
. If now the whole apparatus be turned through , the difference will be in
the opposite direction, hence the displacement of the interference-fringes should be
.
Considering only the velocity of the earth in its orbit, this would be
. If, as was
the case in the first experiment,
waves of yellow light, the displacement to be
expected would be of the distance between the interference fringes.
In the first experiment one of the principal difficulties encountered was that of revolving the apparatus without producing distortion; and another was its extreme sensitiveness to vibration. This was so great that it was impossible to see the interference fringes except at brief intervals when working in the city, even at two o'clock in the morning. Finally, as before remarked, the quantity to be observed, namely, a displacement of something less than a twentieth of the distance between the interference fringes may have been too small to be detected when masked by experimental errors. The first named difficulties were entirely overcome by mounting the apparatus on a massive stone floating on mercury; and the second by increasing, by repeated reflection, the path of the light to about ten times its former value.
The apparatus is represented in perspective in fig. 3, in plan in fig. 4, and in vertical section in fig. 5.
Fig. 3.
The stone (fig. 5) is about
and
thick. It rests on an annular
wooden float ,
outside diameter,
inside diameter, and
thick. The float rests on mercury contained in the cast-iron trough ,
thick,
and of such dimensions as to leave a clearance of about one centimeter around the float. A
pin , guided by arms
, fits into a socket e attached to the float. The pin may be
pushed into the socket or be withdrawn, by a lever pivoted at . This pin keeps the float
concentric with the trough, but does not bear any part of the weight of the stone. The
annular iron trough rests on a bed of cement on a low brick pier built in the form of a
hollow octagon.
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
6/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
Fig. 4.
At each corner of the stone were placed four mirrors
fig. 4. Near the center of the
stone was a plane-parallel glass . These were so disposed that light from an argand burner
, passing through a lens, fell on so as to be in part reflected to ; the two pencils
followed the paths indicated in the figure,
and
respectively, and
were observed by the telescope . Both and revolved with the stone. The mirrors were
of speculum metal carefully worked to optically plane surfaces five centimeters in diameter,
and the glasses and were plane-parallel and of the same thickness,
;
their surfaces measured by
. The second of these was placed in the path
of one of the pencils to compensate for the passage of the other through the same thickness
of glass. The whole of the optical portion of the apparatus was kept covered with a wooden
cover to prevent air currents and rapid changes of temperature.
The adjustment was effected as follows:—The mirrors having been adjusted by screws in the castings which held the mirrors, against which they were pressed by springs, till light from both pencils could be seen in the telescope, the lengths of the two paths were measured by a light wooden rod reaching diagonally from mirror to mirror, the distance being read from a small steel scale to tenths of millimeters. The difference in the lengths of the two paths was then annulled by moving the mirror . This mirror had three
adjustments; it had an adjustment in altitude and one in azimuth, like all the other mirrors, but finer; it also had an adjustment in the direction of the incident ray, sliding forward or backward, but keeping very accurately parallel to its former plane. The three adjustments of this mirror could be made with the wooden cover in position.
The paths being now approximately equal, the two images of the source of light or of
some well-defined object placed in front of the condensing lens, were made to coincide, the
telescope was now adjusted for distinct vision of the expected interference bands, and
sodium light was substituted for white light, when the interference bands appeared. These
were now made as clear as possible by adjusting the mirror ; then white light was
restored, the screw altering the length of path was very slowly moved (one turn of a screw
of one hundred threads to the inch altering the path nearly
till the
colored interference fringes reappeared in white light. These were now given a convenient
width and position, and the apparatus was ready for observation.
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
7/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
Fig. 5.
The observations were conducted as follows:—Around the cast-iron trough were sixteen equidistant marks. The apparatus was revolved very slowly (one turn in six minutes) and after a few minutes the cross wire of the micrometer was set on the clearest of the interference fringes at the instant of passing one of the marks. The motion was so slow that this could be done readily and accurately. The reading of the screw-head on the micrometer was noted, and a very slight and gradual impulse was given to keep up the motion of the stone; on passing the second mark, the same process was repeated, and this was continued till the apparatus had completed six revolutions. It was found that by keeping the apparatus in slow uniform motion, the results were much more uniform and consistent than when the stone was brought to rest for every observation; for the effects of strains could be noted for at least half a minute after the stone came to rest, and during this time effects of change of temperature came into action.
The following tables give the means of the six readings; the first, for observations made
near noon, the second, those near six o'clock in the evening. The readings are divisions of
the screw-heads. The width of the fringes varied from
, the mean value
being near , so that one division means
. The rotation in the
observations at noon was contrary to, and in the evening observations, with, that of the
hands of a watch.
NOON OBSERVATIONS.
16. 1. 2. 3. 4. 5. 6. 7. 8.
July 8
44.7 44.0 43.5 39.7 35.2 34.7 34.3 32.5 28.2
July 9
57.4 57.3 58.2 59.2 58.7 60.2 60.8 62.0 61.5
July 11
27.3 23.5 22.0 19.3 19.2 19.3 18.7 18.8 16.2
Mean
43.1 41.6 41.2 39.4 37.7 38.1 37.9 37.8 35.3
Mean in w. l. .862 .832 .824 .788 .754 .762 .758 .756 .706
.706 .692 .686 .688 .688 .678 .672 .628 .616
Final mean .784 .762 .755 .738 .721 .720 .715 .692 .661
9. 10. 11. 12. 13. 14. 15. 16.
July 8
26.2 23.8 23.2 20.3 18.7 17.5 16.8 13.7
July 9
63.3 65.8 67.3 69.7 70.7 73.0 70.2 72.2
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
8/20
9/2/23, 5:01 PM
July 11 Mean Mean in w. l.
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
9. 10. 11. 12. 13. 14. 15. 16. 14.3 13.3 12.8 13.3 12.3 10.2 7.3 6.5 34.6 34.3 34.4 34.4 33.9 33.6 31.4 30.8 .692 .686 .688 .688 .678 .672 .628 .616
Final mean ... ... ... ... ... ... ... ...
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
9/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
P.M. OBSERVATIONS.
July 8 July 9 July 12 Mean Mean in w. l.
Final mean
July 8 July 9 July 12 Mean Mean in w. l.
16. 61.2 26.0 66.8 51.3 1.026 1.068 1.047
9. 71.3 35.8 55.7 54.3 1.086
1. 63.3 26.0 66.5 51.9 1.038 1.086 1.062
10. 71.3 36.5 53.7 53.8 1.076
2. 63.3 28.2 66.0 52.5 1.050 1.076 1.063
11. 70.5 37.3 54.7 54.2 1.084
3. 68.2 29.2 64.3 53.9 1.078 1.084 1.081
12. 71.2 38.8 55.0 55.0 1.100
4. 67.7 31.5 62.2 53.8 1.076 1.100 1.088
13. 71.2 41.0 58.2 56.8 1.136
5. 69.3 32.0 61.0 54.1 1.082 1.136 1.109
14. 70.5 42.7 58.5 57.2 1.144
6. 70.3 31.3 61.3 54.3 1.086 1.144 1.115
15. 72.5 43.7 57.0 57.7 1.154
7. 69.8 31.7 59.7 53.7 1.074 1.154 1.114
16. 75.7 44.0 56.0 58.6 1.172
8. 69.0 33.0 58.2 53.4 1.068 1.172 1.120
Final mean ...
...
...
...
...
...
...
...
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
10/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
The results of the observations are expressed graphically in fig. 6.
Fig. 6.
The upper is the curve for the observations at noon, and the lower that for the evening observations. The dotted curves represent one eighth of the theoretical displacements. It seems fair to conclude from the figure that if there is any displacement due to the relative motion of the earth and the luminiferous æther, this cannot be much greater than of the distance between the fringes.
Considering the motion of the earth in its orbit only, this displacement should be
The distance D was about eleven meters, or
of yellow light; hence
the displacement to be expected was
. The actual displacement was certainly less
than the twentieth part of this, and probably less than the fortieth part. But since the
displacement is proportional to the square of the velocity, the relative velocity of the earth
and the æther is probably less than one sixth the earth's orbital velocity, and certainly less
than one-fourth.
In what precedes, only the orbital motion of the earth is considered. If this is combined with the motion of the solar system, concerning which but little is known with certainty, the result would have to be modified; and it is just possible that the resultant velocity at the time of the observations was small though the chances are much against it. The experiment will therefore be repeated at intervals of three months, and thus all uncertainty will be avoided.
It appears, from all that precedes, reasonably certain that if there be any relative motion between the earth and the luminiferous æther, it must be small; quite small enough entirely to refute Fresnel's explanation of aberration. Stokes has given a theory of aberration which assumes the æther at the earth's surface to be at rest with regard to the latter, and only requires in addition that the relative velocity have a potential; but Lorentz shows that these conditions are incompatible. Lorentz then proposes a modification which combines some ideas of Stokes and Fresnel, and assumes the existence of a potential, together with Fresnel's coefficient. If now it were legitimate to conclude from the present work that the æther is at rest with regard to the earth's surface, according to Lorentz there could not be a velocity potential, and his own theory also fails.
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
11/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
Supplement.
It is obvious from what has gone before that it would be hopeless to attempt to solve the question of the motion of the solar system by observations of optical phenomena at the surface of the earth. But it is not impossible that at even moderate distances above the level of the sea, at the top of an isolated mountain peak, for instance, the relative motion might be perceptible in an apparatus like that used in these experiments. Perhaps if the experiment should ever be tried in these circumstances, the cover should be of glass, or should be removed.
It may be worth while to notice another method for multiplying the square of the aberration sufficiently to bring it within the range of observation, which has presented itself during the preparation of this paper. This is founded on the fact that reflection from surfaces in motion varies from the ordinary laws of reflection.
Figures 1, 2, 3 and 4 from Supplement.
Let (fig. 1 (Figure 07)) be a plane wave falling on the mirror . If the mirror is at rest, the wave front after reflection will be .
at an incidence of
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
12/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
Now suppose the mirror to move in a direction which makes an angle with its normal, with a velocity . Let be the velocity of light in the æther supposed stationary, and let be the increase in the distance the light has to travel to reach . In this time the mirror will
have moved a distance
.
We have
which put , and
In order to find the new wave front, draw the arc with as a center and as radius;
the tangent to this arc from will be the new wave-front, and the normal to the tangent from
will be the new direction. This will differ from the direction by the angle which it is
required to find. From the equality of the triangles and it follows that
,
,
or neglecting terms of the order ,
Now let the light fall on a parallel mirror facing the first, we should then have
and the total deviation would be
where is the angle of aberration, if only the orbital motion of the earth is considered. The maximum displacement obtained by revolving the whole apparatus through would be
With fifty such couples the displacement would be ''. But astronomical observations in circumstances far less favorable than those in which these may be taken have been made to hundredths of a second; so that this new method bids fair to be at least as sensitive as the former.
The arrangement of apparatus might be as in fig. 2 (Figure 07); , in the focus of the
lens , is a slit.
are two glass mirrors optically plane and so silvered as to allow say
one twentieth of the light to pass through, and reflecting say ninety per cent. The intensity
of the light falling on the observing telescope would be about one millionth of the
original intensity, so that if sunlight or the electric arc were used it could still be readily
seen. The mirrors and , would differ from parallelism sufficiently to separate the
successive images. Finally, the apparatus need not be mounted so as to revolve, as the
earth's rotation would be sufficient.
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
13/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
If it were possible to measure with sufficient accuracy the velocity of light without returning the ray to its starting point, the problem of measuring the first power of the relative velocity of the earth with respect to the æther would be solved. This may not be as hopeless as might appear at first sight, since the difficulties are entirely mechanical and may possibly be surmounted in the course of time.
For example, suppose (fig. 3 (Figure 07)) and , two mirrors revolving with equal
velocity in opposite directions. It is evident that light from will form a stationary image at and similarly light from will form a stationary image at . If now the velocity of the
mirrors be increased sufficiently, their phases still being exactly the same, both images will be deflected from and , in inverse proportion to the velocities of light in the two directions; or, if the two deflections are made equal, and the difference of phase of the mirrors be simultaneously measured, this will evidently be proportional to the difference of velocity in the two directions. The only real difficulty lies in this measurement. The following is perhaps a possible solution.
(fig. 4 (Figure 07)) are two gratings on which sunlight is concentrated. These are
placed so that after falling on the revolving mirrors and , the light forms images of the
gratings at and , two very sensitive selenium cells in circuit with a battery and a
telephone. If everything be symmetrical, the sound in the telephone will be a maximum. If now one of the slits be displaced through half the distance between the image of the grating bars, there will be silence. Suppose now that the two deflections having been made exactly equal, the slit is adjusted for silence. Then if the experiment be repeated when the earth's rotation has turned the whole apparatus through , and the deflections are again made equal, there will no longer be silence, and the angular distance through which must be moved to restore silence will measure the required difference in phase.
There remain three other methods, all astronomical, for attacking the problem of the motion of the solar system through space.
1. The telescopic observation of the proper motions of the stars. This has given us a highly probably determination of the direction of this motion, but only a guess as to its amount.
2. The spectroscopic observation of the motion of stars in the line of sight. This could furnish data for the relative motions only, though it seems likely that by the immense improvements in the photography of stellar spectra, the information thus obtained will be far more accurate than any other.
3. Finally there remains the determination of the velocity of light by observations of the eclipses of Jupiter's satellites. If the improved photometric methods practiced at the Harvard observatory make it possible to observe these with sufficient accuracy, the difference in the results found for the velocity of light when Jupiter is nearest to and farthest from the line of motion will give, not merely the motion of the solar system with reference to the stars, but with reference to the luminiferous æther itself.
[1] Communicated by the Authors.
This research was carried out with the aid of the Bache Found.
[2] It may be noticed that most writers admit the sufficiency of the explanation according to the emission theory of light; while in fact the difficulty is even greater than according to the undulatory theory. For on the emission theory the velocity of light must be greater in the water telescope, and therefore the angle of aberration should be less; hence, in order to reduce it to its true value, we must make the absurd hypothesis that the motion of the water in the telescope carries the ray of light in the opposite direction!
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
14/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
[3] Comptes Rendus, XXXIII, 349, 1851; Pogg. Ann. Ergänzungsband, III. 457, 1853; Ann. Chim. Phys., III, lvii, 385, 1859.
[4] "Influence of Motion of the Medium on the Velocity of Light." Am. J. Sci, III, xxxi, 377, (1886).
[5] It may be objected that it may escape by the space between the mercury and the walls; but this could be prevented by amalgamating the latter.
[6] Archives Néerlandaises, XXI, 2me livr. Phil. Mag. V, xiii, p. 236.
[7] "The Relative Motion of the Earth and the Luminiferous Æther," by Albert A. Michelson. Am. J. Sci., III, xxii, p. 120.
[8] It may be mentioned here that the error was pointed out to the author of the former paper by M. A. Potier, of Paris, in the winter of 1881.
[9] "De l'Influence du Mouvement de la Terre sur les Phen. Lum." Archives Néerlandaises, XXI, 2me livr., (1886).
*** END OF THE PROJECT GUTENBERG EBOOK ON THE RELATIVE MOTION OF THE EARTH AND THE LUMINIFEROUS ÆTHER ***
Updated editions will replace the previous one—the old editions will be renamed.
Creating the works from print editions not protected by U.S. copyright law means that no one owns a United States copyright in these works, so the Foundation (and you!) can copy and distribute it in the United States without permission and without paying copyright royalties. Special rules, set forth in the General Terms of Use part of this license, apply to copying and distributing Project Gutenberg™ electronic works to protect the PROJECT GUTENBERG™ concept and trademark. Project Gutenberg is a registered trademark, and may not be used if you charge for an eBook, except by following the terms of the trademark license, including paying royalties for use of the Project Gutenberg trademark. If you do not charge anything for copies of this eBook, complying with the trademark license is very easy. You may use this eBook for nearly any purpose such as creation of derivative works, reports, performances and research. Project Gutenberg eBooks may be modified and printed and given away—you may do practically ANYTHING in the United States with eBooks not protected by U.S. copyright law. Redistribution is subject to the trademark license, especially commercial redistribution.
START: FULL LICENSE
THE FULL PROJECT GUTENBERG LICENSE
PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK
To protect the Project Gutenberg™ mission of promoting the free distribution of electronic works, by using or distributing this work (or any other work associated in any way with the phrase “Project Gutenberg”), you agree to comply with all the terms of the Full Project Gutenberg™ License available with this file or online at www.gutenberg.org/license.
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
15/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
Section 1. General Terms of Use and Redistributing Project Gutenberg™ electronic works
1.A. By reading or using any part of this Project Gutenberg™ electronic work, you indicate that you have read, understand, agree to and accept all the terms of this license and intellectual property (trademark/copyright) agreement. If you do not agree to abide by all the terms of this agreement, you must cease using and return or destroy all copies of Project Gutenberg™ electronic works in your possession. If you paid a fee for obtaining a copy of or access to a Project Gutenberg™ electronic work and you do not agree to be bound by the terms of this agreement, you may obtain a refund from the person or entity to whom you paid the fee as set forth in paragraph 1.E.8.
1.B. “Project Gutenberg” is a registered trademark. It may only be used on or associated in any way with an electronic work by people who agree to be bound by the terms of this agreement. There are a few things that you can do with most Project Gutenberg™ electronic works even without complying with the full terms of this agreement. See paragraph 1.C below. There are a lot of things you can do with Project Gutenberg™ electronic works if you follow the terms of this agreement and help preserve free future access to Project Gutenberg™ electronic works. See paragraph 1.E below.
1.C. The Project Gutenberg Literary Archive Foundation (“the Foundation” or PGLAF), owns a compilation copyright in the collection of Project Gutenberg™ electronic works. Nearly all the individual works in the collection are in the public domain in the United States. If an individual work is unprotected by copyright law in the United States and you are located in the United States, we do not claim a right to prevent you from copying, distributing, performing, displaying or creating derivative works based on the work as long as all references to Project Gutenberg are removed. Of course, we hope that you will support the Project Gutenberg™ mission of promoting free access to electronic works by freely sharing Project Gutenberg™ works in compliance with the terms of this agreement for keeping the Project Gutenberg™ name associated with the work. You can easily comply with the terms of this agreement by keeping this work in the same format with its attached full Project Gutenberg™ License when you share it without charge with others.
1.D. The copyright laws of the place where you are located also govern what you can do with this work. Copyright laws in most countries are in a constant state of change. If you are outside the United States, check the laws of your country in addition to the terms of this agreement before downloading, copying, displaying, performing, distributing or creating derivative works based on this work or any other Project Gutenberg™ work. The Foundation makes no representations concerning the copyright status of any work in any country other than the United States.
1.E. Unless you have removed all references to Project Gutenberg:
1.E.1. The following sentence, with active links to, or other immediate access to, the full Project Gutenberg™ License must appear prominently whenever any copy of a Project Gutenberg™ work (any work on which the phrase “Project Gutenberg” appears, or with which the phrase “Project Gutenberg” is associated) is accessed, displayed, performed, viewed, copied or distributed:
This eBook is for the use of anyone anywhere in the United States and most other parts of the world at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
16/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
the Project Gutenberg License included with this eBook or online at www.gutenberg.org. If you are not located in the United States, you will have to check the laws of the country where you are located before using this eBook.
1.E.2. If an individual Project Gutenberg™ electronic work is derived from texts not protected by U.S. copyright law (does not contain a notice indicating that it is posted with permission of the copyright holder), the work can be copied and distributed to anyone in the United States without paying any fees or charges. If you are redistributing or providing access to a work with the phrase “Project Gutenberg” associated with or appearing on the work, you must comply either with the requirements of paragraphs 1.E.1 through 1.E.7 or obtain permission for the use of the work and the Project Gutenberg™ trademark as set forth in paragraphs 1.E.8 or 1.E.9.
1.E.3. If an individual Project Gutenberg™ electronic work is posted with the permission of the copyright holder, your use and distribution must comply with both paragraphs 1.E.1 through 1.E.7 and any additional terms imposed by the copyright holder. Additional terms will be linked to the Project Gutenberg™ License for all works posted with the permission of the copyright holder found at the beginning of this work.
1.E.4. Do not unlink or detach or remove the full Project Gutenberg™ License terms from this work, or any files containing a part of this work or any other work associated with Project Gutenberg™.
1.E.5. Do not copy, display, perform, distribute or redistribute this electronic work, or any part of this electronic work, without prominently displaying the sentence set forth in paragraph 1.E.1 with active links or immediate access to the full terms of the Project Gutenberg™ License.
1.E.6. You may convert to and distribute this work in any binary, compressed, marked up, nonproprietary or proprietary form, including any word processing or hypertext form. However, if you provide access to or distribute copies of a Project Gutenberg™ work in a format other than “Plain Vanilla ASCII” or other format used in the official version posted on the official Project Gutenberg™ website (www.gutenberg.org), you must, at no additional cost, fee or expense to the user, provide a copy, a means of exporting a copy, or a means of obtaining a copy upon request, of the work in its original “Plain Vanilla ASCII” or other form. Any alternate format must include the full Project Gutenberg™ License as specified in paragraph 1.E.1.
1.E.7. Do not charge a fee for access to, viewing, displaying, performing, copying or distributing any Project Gutenberg™ works unless you comply with paragraph 1.E.8 or 1.E.9.
1.E.8. You may charge a reasonable fee for copies of or providing access to or distributing Project Gutenberg™ electronic works provided that:
• You pay a royalty fee of 20% of the gross profits you derive from the use of Project Gutenberg™ works calculated using the method you already use to calculate your applicable taxes. The fee is owed to the owner of the Project Gutenberg™ trademark, but he has agreed to donate royalties under this paragraph to the Project Gutenberg Literary Archive Foundation. Royalty payments must be paid within 60 days following each date on which you prepare (or are legally required to prepare) your periodic tax returns. Royalty payments should be clearly marked as such and sent to the Project Gutenberg Literary Archive Foundation at the address specified in Section
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
17/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
4, “Information about donations to the Project Gutenberg Literary Archive Foundation.”
• You provide a full refund of any money paid by a user who notifies you in writing (or by e-mail) within 30 days of receipt that s/he does not agree to the terms of the full Project Gutenberg™ License. You must require such a user to return or destroy all copies of the works possessed in a physical medium and discontinue all use of and all access to other copies of Project Gutenberg™ works.
• You provide, in accordance with paragraph 1.F.3, a full refund of any money paid for a work or a replacement copy, if a defect in the electronic work is discovered and reported to you within 90 days of receipt of the work.
• You comply with all other terms of this agreement for free distribution of Project Gutenberg™ works.
1.E.9. If you wish to charge a fee or distribute a Project Gutenberg™ electronic work or group of works on different terms than are set forth in this agreement, you must obtain permission in writing from the Project Gutenberg Literary Archive Foundation, the manager of the Project Gutenberg™ trademark. Contact the Foundation as set forth in Section 3 below.
1.F.
1.F.1. Project Gutenberg volunteers and employees expend considerable effort to identify, do copyright research on, transcribe and proofread works not protected by U.S. copyright law in creating the Project Gutenberg™ collection. Despite these efforts, Project Gutenberg™ electronic works, and the medium on which they may be stored, may contain “Defects,” such as, but not limited to, incomplete, inaccurate or corrupt data, transcription errors, a copyright or other intellectual property infringement, a defective or damaged disk or other medium, a computer virus, or computer codes that damage or cannot be read by your equipment.
1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the “Right of Replacement or Refund” described in paragraph 1.F.3, the Project Gutenberg Literary Archive Foundation, the owner of the Project Gutenberg™ trademark, and any other party distributing a Project Gutenberg™ electronic work under this agreement, disclaim all liability to you for damages, costs and expenses, including legal fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH DAMAGE.
1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a defect in this electronic work within 90 days of receiving it, you can receive a refund of the money (if any) you paid for it by sending a written explanation to the person you received the work from. If you received the work on a physical medium, you must return the medium with your written explanation. The person or entity that provided you with the defective work may elect to provide a replacement copy in lieu of a refund. If you received the work electronically, the person or entity providing it to you may choose to give you a second opportunity to receive the work electronically in lieu
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
18/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
of a refund. If the second copy is also defective, you may demand a refund in writing without further opportunities to fix the problem.
1.F.4. Except for the limited right of replacement or refund set forth in paragraph 1.F.3, this work is provided to you ‘AS-IS’, WITH NO OTHER WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE.
1.F.5. Some states do not allow disclaimers of certain implied warranties or the exclusion or limitation of certain types of damages. If any disclaimer or limitation set forth in this agreement violates the law of the state applicable to this agreement, the agreement shall be interpreted to make the maximum disclaimer or limitation permitted by the applicable state law. The invalidity or unenforceability of any provision of this agreement shall not void the remaining provisions.
1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the trademark owner, any agent or employee of the Foundation, anyone providing copies of Project Gutenberg™ electronic works in accordance with this agreement, and any volunteers associated with the production, promotion and distribution of Project Gutenberg™ electronic works, harmless from all liability, costs and expenses, including legal fees, that arise directly or indirectly from any of the following which you do or cause to occur: (a) distribution of this or any Project Gutenberg™ work, (b) alteration, modification, or additions or deletions to any Project Gutenberg™ work, and (c) any Defect you cause.
Section 2. Information about the Mission of Project Gutenberg™
Project Gutenberg™ is synonymous with the free distribution of electronic works in formats readable by the widest variety of computers including obsolete, old, middleaged and new computers. It exists because of the efforts of hundreds of volunteers and donations from people in all walks of life.
Volunteers and financial support to provide volunteers with the assistance they need are critical to reaching Project Gutenberg™’s goals and ensuring that the Project Gutenberg™ collection will remain freely available for generations to come. In 2001, the Project Gutenberg Literary Archive Foundation was created to provide a secure and permanent future for Project Gutenberg™ and future generations. To learn more about the Project Gutenberg Literary Archive Foundation and how your efforts and donations can help, see Sections 3 and 4 and the Foundation information page at www.gutenberg.org.
Section 3. Information about the Project Gutenberg Literary Archive Foundation
The Project Gutenberg Literary Archive Foundation is a non-profit 501(c)(3) educational corporation organized under the laws of the state of Mississippi and granted tax exempt status by the Internal Revenue Service. The Foundation’s EIN or federal tax identification number is 64-6221541. Contributions to the Project Gutenberg Literary Archive Foundation are tax deductible to the full extent permitted by U.S. federal laws and your state’s laws.
The Foundation’s business office is located at 809 North 1500 West, Salt Lake City, UT 84116, (801) 596-1887. Email contact links and up to date contact information can be found at the Foundation’s website and official page at www.gutenberg.org/contact
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
19/20
9/2/23, 5:01 PM
On the Relative Motion of the Earth and the Luminiferous Æther | Project Gutenberg
Section 4. Information about Donations to the Project Gutenberg Literary Archive Foundation
Project Gutenberg™ depends upon and cannot survive without widespread public support and donations to carry out its mission of increasing the number of public domain and licensed works that can be freely distributed in machine-readable form accessible by the widest array of equipment including outdated equipment. Many small donations ($1 to $5,000) are particularly important to maintaining tax exempt status with the IRS.
The Foundation is committed to complying with the laws regulating charities and charitable donations in all 50 states of the United States. Compliance requirements are not uniform and it takes a considerable effort, much paperwork and many fees to meet and keep up with these requirements. We do not solicit donations in locations where we have not received written confirmation of compliance. To SEND DONATIONS or determine the status of compliance for any particular state visit www.gutenberg.org/donate.
While we cannot and do not solicit contributions from states where we have not met the solicitation requirements, we know of no prohibition against accepting unsolicited donations from donors in such states who approach us with offers to donate.
International donations are gratefully accepted, but we cannot make any statements concerning tax treatment of donations received from outside the United States. U.S. laws alone swamp our small staff.
Please check the Project Gutenberg web pages for current donation methods and addresses. Donations are accepted in a number of other ways including checks, online payments and credit card donations. To donate, please visit: www.gutenberg.org/donate.
Section 5. General Information About Project Gutenberg™ electronic works
Professor Michael S. Hart was the originator of the Project Gutenberg™ concept of a library of electronic works that could be freely shared with anyone. For forty years, he produced and distributed Project Gutenberg™ eBooks with only a loose network of volunteer support.
Project Gutenberg™ eBooks are often created from several printed editions, all of which are confirmed as not protected by copyright in the U.S. unless a copyright notice is included. Thus, we do not necessarily keep eBooks in compliance with any particular paper edition.
Most people start at our website which has the main PG search facility: www.gutenberg.org.
This website includes information about Project Gutenberg™, including how to make donations to the Project Gutenberg Literary Archive Foundation, how to help produce our new eBooks, and how to subscribe to our email newsletter to hear about new eBooks.
https://www.gutenberg.org/cache/epub/70888/pg70888-images.html
20/20