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Often appears with: matter, motion, and cause · logic, method, and demonstration · reason and the intellect · strata, rocks, and the geological record · weather, storms, and the seasons · fate, destiny, and necessity · the earth and its formation · geography and the description of places · perception and the senses · fossils and the record of past life · volcanoes, earthquakes, and catastrophe · the heavens and the stars
Usually: curiosity (383) · argument (368) · skepticism (177) · detachment (159) · narrative (78) · reflection (68) · commentary or gloss (67) · wonder (42) · record or table (40) · description (20)
“The law of the conservation of the mass of a system becomes identical with the law of the conservation of energy, and is only valid provided that the system neither takes up nor sends out energy.” Albert Einstein, Relativity: The Special and General Theory · insight
“The special theory of relativity has crystallised out from the Maxwell-Lorentz theory of electromagnetic phenomena.” Albert Einstein, Relativity: The Special and General Theory · observation
“But on the basis of the theory of relativity the method of interpretation is incomparably more satisfactory.” Albert Einstein, Relativity: The Special and General Theory · observation
“From this we conclude, that, in general, rays of light are propagated curvilinearly in gravitational fields.” Albert Einstein, Relativity: The Special and General Theory · insight
“On the basis of the general theory of relativity, it is found that the ellipse of every planet round the sun must necessarily rotate in the manner indicated above; that for all the planets, with the exception of Mercury, this rotation is too small to be detected with the delicacy of observation possible at the present time; but that in the case of Mercury it must amount to 43 seconds of arc per century, a result which is strictly in agreement with observation.” Albert Einstein, Relativity: The Special and General Theory · observation
“Undaunted by the [first world] war and by difficulties of both a material and a psychological nature aroused by the war, these societies equipped two expeditions—to Sobral (Brazil), and to the island of Principe (West Africa)—and sent several of Britain’s most celebrated astronomers in order to obtain photographs of the solar eclipse of 29th May, 1919.” Albert Einstein, Relativity: The Special and General Theory · observation
“In the interest of clearness, it appeared to me inevitable that I should repeat myself frequently, without paying the slightest attention to the elegance of the presentation.” Albert Einstein, Relativity: The Special and General Theory · precept
“The present book is intended, as far as possible, to give an exact insight into the theory of Relativity to those readers who, from a general scientific and philosophical point of view, are interested in the theory, but who are not conversant with the mathematical apparatus of theoretical physics.” Albert Einstein, Relativity: The Special and General Theory · observation
“We call the magnitude ds the “distance” apart of the two events or four-dimensional points.” Albert Einstein, Relativity: The Special and General Theory · observation
“Thus we have obtained the Lorentz transformation. The Lorentz transformation represented by (8) and (9) still requires to be generalised.” Albert Einstein, Relativity: The Special and General Theory · observation
“For some time after the rest of the animal was completely dead from the effects of salt water or any other cause, this organ still retained its vitality.” Charles Darwin, The Voyage of the Beagle · observation
“It seems probable that this additional migration has happened since the time of Azara.” Charles Darwin, The Voyage of the Beagle · observation
Pepys records scientific talk on sinking ships and AURUM FULMINANS, notes his queen’s birthday celebrations with guns and bonfires, and reports governance discussions about credit and potential quarantine measures.
and it was pleasant to see how Blackburne himself did act it, how when the Commissioners of the Admiralty would enquire of the captains and admirals of such and such men, how they would with a sigh and casting up the eyes say, "such a man fears the Lord," or, "I hope such a man hath the Spirit of God." But he tells me that there was a cruel articling against Pen after one fight, for cowardice, in putting himself wit…
In early May 1665 Pepys travels by water to Greenwich and Deptford with scientists, observes experiments on coach springs, hears of the sudden death of Chief Justice Hide, visits Evelyn’s garden, and continues Navy preparations and trials of deserters and pressmen.
20th. This night I am told the first play is played in White Hall noon-hall, which is now turned to a house of playing. 23rd. To White Hall chapel, and heard the famous young Stillingfleete, [Edward Stillingfleet, a most learned Divine, consecrated Bishop of Worcester, 1689, Ob. 1699.] whom I knew at Cambridge, and he is now newly admitted one of the King's chaplains. And was presented, they say, to my Lord Treas…
Pepys visits Lady Denham’s case again, receives gold from Mr. Stokes, and views the skeleton of Bishop Robert Braybrooke exposed after the Great Fire, while noting further violence and scientific experiments.
such like; but, as Dr. Croone says, may, if it takes, be of mighty use to man's health, for the amending of bad blood by borrowing from a better body. 15th. To Mrs. Pierce's, where I find her as fine as possible, and Mr. Pierce going to the ball at night at Court, it being the Queene's birthday. I also to the ball, and with much ado got up to the loft, where with much trouble I could see very well. Anon the house…
Pepys reunites with Richard Cumberland after seven years, hears political news about Coventry and Arlington’s offices, a marriage plan for the Duke of Richmond, and Caesar’s angling “experiment” with a minikin gut-string.
him (Sir G. Carteret) how those very people (meaning the Prince, and Duke of Albemarle) are punished in the same kind as they did seek to abuse my Lord Sandwich. 18th. Comes my old good friend Mr. Richard Cumberland [Richard Cumberland educated at St. Paul's School, and Magdalene College, Cambridge, made Bishop of Peterborough 1691. Ob. 1718, aged 86.] to see me, being newly come to town, whom I have not seen almo…
He describes how subtle reductions in checks cause rapid increases, likening nature to wedges driven inward, and notes that the strongest checks are often obscure and vary by life stage and enemies.
the geometrical ratio of increase, the result of which never fails to be surprising, simply explains the extraordinarily rapid increase and wide diffusion of naturalised productions in their new homes. In a state of nature almost every plant produces seed, and amongst animals there are very few which do not annually pair. Hence we may confidently assert, that all plants and animals are tending to increase at a geome…
Darwin catalogs potential checks—severe destruction of eggs, seedlings, prey availability, food limits, vermin control, and climate—arguing climate mainly matters by altering competition and predators.
compared to a yielding surface, with ten thousand sharp wedges packed close together and driven inwards by incessant blows, sometimes one wedge being struck, and then another with greater force. What checks the natural tendency of each species to increase in number is most obscure. Look at the most vigorous species; by as much as it swarms in numbers, by so much will its tendency to increase be still further increas…
He introduces natural selection as the process that preserves beneficial variations and rejects harmful ones, compares its scope to human selection, and explains how changing conditions and isolation create “unoccupied places” for improvement.
NATURAL SELECTION. Natural Selection: its power compared with man’s selection, its power on characters of trifling importance, its power at all ages and on both sexes. Sexual Selection. On the generality of intercrosses between individuals of the same species. Circumstances favourable and unfavourable to Natural Selection, namely, intercrossing, isolation, number of individuals. Slow action. Extinction caused by Nat…
Darwin weighs the roles of habit, use and disuse, and natural selection in acclimatization, citing agricultural advice, climate-tuned plant varieties in the United States, and experiments (or lack of them) on Jerusalem artichoke and kidney-beans.
or sub-tropical in their habits, ought not to be looked at as anomalies, but merely as examples of a very common flexibility of constitution, brought, under peculiar circumstances, into play. How much of the acclimatisation of species to any peculiar climate is due to mere habit, and how much to the natural selection of varieties having different innate constitutions, and how much to both means combined, is a very o…
He reports his own skepticism and observations of Formica sanguinea slave-making ants in southern England, describing their nestmates, slave-like behavior, and differences from other slave-making species.
these well-ascertained facts? If we had not known of any other slave-making ant, it would have been hopeless to have speculated how so wonderful an instinct could have been perfected. Formica sanguinea was likewise first discovered by P. Huber to be a slave-making ant. This species is found in the southern parts of England, and its habits have been attended to by Mr. F. Smith, of the British Museum, to whom I am muc…
Darwin details further ant experiments and encounters, including slave-maker migrations, raids on pupae, discrimination between pupae types, and interactions between slave-making and independent ant species in the field.
difference in the usual habits of the masters and slaves in the two countries, probably depends merely on the slaves being captured in greater numbers in Switzerland than in England. One day I fortunately chanced to witness a migration from one nest to another, and it was a most interesting spectacle to behold the masters carefully carrying, as Huber has described, their slaves in their jaws. Another day my attentio…
He cites an experimental test by separating combs and inserting a wax strip, then observes bees excavating spherical pits that intersect and become shallow basins, after which they build wax walls along intersection lines.
I wrote to Professor Miller, of Cambridge, and this geometer has kindly read over the following statement, drawn up from his information, and tells me that it is strictly correct:— If a number of equal spheres be described with their centres placed in two parallel layers; with the centre of each sphere at the distance of radius x the square root of 2 or radius x 1.41421 (or at some lesser distance), from the centres…
Darwin describes an experiment with bees altering wax excavation geometry: a vermilion-wax ridge leads bees to stop excavating so flat basal plates form along the planes where opposite basins meet.
each hexagonal prism was built upon the festooned edge of a smooth basin, instead of on the straight edges of a three-sided pyramid as in the case of ordinary cells. I then put into the hive, instead of a thick, square piece of wax, a thin and narrow, knife-edged ridge, coloured with vermilion. The bees instantly began on both sides to excavate little basins near to each other, in the same way as before; but the rid…
He argues bees can build proper cell shapes by standing at fixed spacing and excavating evenly, works that depend on rough walls, intermediate planes, and later refinement, while noting differences with Huber’s account.
in the opposed cells and push and bend the ductile and warm wax (which as I have tried is easily done) into its proper intermediate plane, and thus flatten it. From the experiment of the ridge of vermilion wax, we can clearly see that if the bees were to build for themselves a thin wall of wax, they could make their cells of the proper shape, by standing at the proper distance from each other, by excavating at the s…
Darwin explains how many bees coordinate implicitly, using a painted vermilion-wax diffusion test, and describes how bees sometimes pull down and rebuild cells at angles before completion.
plates of the pyramidal basis being about twice as thick. By this singular manner of building, strength is continually given to the comb, with the utmost ultimate economy of wax. It seems at first to add to the difficulty of understanding how the cells are made, that a multitude of bees all work together; one bee after working a short time at one cell going to another, so that, as Huber has stated, a score of indivi…
Darwin explains decreasing hybrid fertility in successive generations by close interbreeding, claims insect prevention and self-pollination distort results, and contrasts Gärtner’s findings with Herbert’s reports of perfectly fertile first-cross hybrids.
species and varieties; but that the evidence from this source graduates away, and is doubtful in the same degree as is the evidence derived from other constitutional and structural differences. In regard to the sterility of hybrids in successive generations; though Gärtner was enabled to rear some hybrids, carefully guarding them from a cross with either pure parent, for six or seven, and in one case for ten generat…
Using Crinum capense vs C. revolutum and Hippeastrum and Lobelia cases, Darwin shows some plants self-sterile yet cross-fertile, suggesting fertility depends on functional self-action rather than pollen quality alone.
to occur in a case of its natural fecundation.” So that we here have perfect, or even more than commonly perfect, fertility in a first cross between two distinct species. This case of the Crinum leads me to refer to a most singular fact, namely, that there are individual plants, as with certain species of Lobelia, and with all the species of the genus Hippeastrum, which can be far more easily fertilised by the polle…
He compares animals with plants, arguing that animal experiments are rarer and often involve improper breeding conditions like inbreeding between brothers and sisters, though he cites some potentially fertile hybrid bird and geese examples.
by examining the flowers of the more sterile kinds of hybrid rhododendrons, which produce no pollen, for he will find on their stigmas plenty of pollen brought from other flowers. In regard to animals, much fewer experiments have been carefully tried than with plants. If our systematic arrangements can be trusted, that is if the genera of animals are as distinct from each other, as are the genera of plants, then we …
Darwin describes experiments on how seeds survive seawater and argues that dried fruits and plant parts can float long distances, using current speeds to suggest sea dispersal across roughly 924 miles.
least of the islands would have been formed, like other mountain-summits, of granite, metamorphic schists, old fossiliferous or other such rocks, instead of consisting of mere piles of volcanic matter. I must now say a few words on what are called accidental means, but which more properly might be called occasional means of distribution. I shall here confine myself to plants. In botanical works, this or that plant i…
He reports follow-up flotation tests by M. Martens, adds examples of drift timber and seeds in soil enclosed by transported wood, and notes seeds surviving long sea voyages in certain circumstances.
to one country might be floated across 924 miles of sea to another country; and when stranded, if blown to a favourable spot by an inland gale, they would germinate. Subsequently to my experiments, M. Martens tried similar ones, but in a much better manner, for he placed the seeds in a box in the actual sea, so that they were alternately wet and exposed to the air like really floating plants. He tried 98 seeds, most…
Darwin argues that birds and other animals spread seeds effectively: gales can blow birds far, seeds may survive passage through bird crops or even predators’ stomachs, and seeds can hitchhike via mud on feet or within fish diets.
few days’ immersion in sea-water; but some taken out of the crop of a pigeon, which had floated on artificial salt-water for 30 days, to my surprise nearly all germinated. Living birds can hardly fail to be highly effective agents in the transportation of seeds. I could give many facts showing how frequently birds of many kinds are blown by gales to vast distances across the ocean. We may I think safely assume that …
Darwin argues that water birds and fish can transport seeds and eggs of freshwater plants and animals over long distances, using mud experiments and examples of germinating seeds in birds’ waste or stomachs.
Colymbetes, once flew on board the ‘Beagle,’ when forty-five miles distant from the nearest land: how much farther it might have flown with a favouring gale no one can tell. With respect to plants, it has long been known what enormous ranges many fresh-water and even marsh-species have, both over continents and to the most remote oceanic islands. This is strikingly shown, as remarked by Alph. de Candolle, in large g…
Plutarch explains Archimedes’ mechanics as geometry turned to practical siege use at King Hiero’s request, contrasting it with philosophers’ suspicion, and recounts Archimedes’ experiments with moving heavy loads.
walls, relying on the abundance and magnificence of his preparations, and on his own previous glory; all which, however, were, it would seem, but trifles for Archimedes and his machines. These machines he had designed and contrived, not as matters of any importance, but as mere amusements in geometry; in compliance with king Hiero's desire and request, some little time before, that he should reduce to practice some …
Kant argues that physics reached scientific progress only after Bacon redirected it, and that experiment must be guided by rational principles that pose questions to nature rather than follow nature blindly.
what indications do we possess to guide us in a renewed investigation, and to enable us to hope for greater success than has fallen to the lot of our predecessors? It appears to me that the examples of mathematics and natural philosophy, which, as we have seen, were brought into their present condition by a sudden revolution, are sufficiently remarkable to fix our attention on the essential circumstances of the chan…
Freud defends the claim that understanding heredity requires understanding infantile sexuality, reviews how little science studied prepubertal sex, then notes later works that begin to address it.
[1] For it is really impossible to have a correct knowledge of the part belonging to heredity without first understanding the part belonging to the infantile. [2] This assertion on revision seemed even to myself so bold that I decided to test its correctness by again reviewing the literature. The result of this second review did not warrant any change in my original statement. The scientific elaboration of the physi…
Freud uses an anatomical analogy: uterine size in newborns may be larger, while Halban’s idea that sexual organs involute after birth for only a few weeks is discussed as unverified or limited.
by pleasure; even in the preparatory changes of the genitals there is a distinct feeling of satisfaction. What relation is there between this unpleasant tension and this feeling of pleasure? Everything relating to the problem of pleasure and pain touches one of the weakest spots of present-day psychology. We shall try if possible to learn something from the determinations of the case in question and to avoid encroac…
Durkheim argues that mana, orenda, and wakan function like scientific notions of force as universal explanatory principles, originating in religion and later borrowed by philosophy and science.
the different beings, he only expresses, in his own language, this modern idea that the world is a system of forces limiting and containing each other and making an equilibrium. The Melanesian attributes this same general efficacy to his mana. It is owing to his mana that a man succeeds in hunting or fighting, that gardens give a good return or that flocks prosper. If an arrow strikes its mark, it is because it is c…
In the Preface to the First Volume, Gibbon claims diligence and accuracy, explains that imperial biographies are collectively cited as the Augustan History, and stresses careful use of original materials.
of the Roman people against the feeble princes of Constantinople; and the elevation of Charlemagne, who, in the year eight hundred, established the second, or German Empire of the West. III. The last and longest of these periods includes about six centuries and a half; from the revival of the Western Empire, till the taking of Constantinople by the Turks, and the extinction of a degenerate race of …
He measures unusual atmospheric dryness near Porto Praya, links haziness to fine dust from Africa rich in infusoria and plant spores, and reports how such dust harms eyes, obscures ships, and correlates with the harmattan winds.
atmospheric dryness was accompanied by continual flashes of lightning. Is it not an uncommon case, thus to find a remarkable degree of aerial transparency with such a state of weather? Generally the atmosphere is hazy; and this is caused by the falling of impalpably fine dust, which was found to have slightly injured the astronomical instruments. The morning before we anchored at Porto Praya, I collected a little p…
Darwin records sailing from Bahia, observing Red Sea–type Trichodesmium erythraeum “sea-sawdust” confervae that discolor the ocean in long bands near Abrolhos and elsewhere, including near Keeling Atoll in the Indian Ocean.
but through the sides of the monster, which has thus been killed. Who would ever have imagined that a little soft fish could have destroyed the great and savage shark? March 18th.--We sailed from Bahia. A few days afterwards, when not far distant from the Abrolhos Islets, my attention was called to a reddish-brown appearance in the sea. The whole surface of the water, as it appeared under a weak lens, seemed as if…
Darwin describes tiny confervae masses near Keeling Atoll and microscopic animalcula that explode after cilia-driven motion, then links sea discoloration off Chile and elsewhere to organic causes rather than non-living material.
accidental injury. I may add, that frequently a pair of these bodies were attached to each other, as represented above, cone beside cone, at that end where the septum occurs. I will add here a few other observations connected with the discoloration of the sea from organic causes. On the coast of Chile, a few leagues north of Concepcion, the Beagle one day passed through great bands of muddy water, exactly like that…
Darwin describes terrestrial Planaria living under rotten wood, detailing their simple anatomy, salt-water effects, and experiments showing regeneration of organs after cutting specimens in half.
by always having something to attract his attention; but in these fertile climates, teeming with life, the attractions are so numerous, that he is scarcely able to walk at all. The few observations which I was enabled to make were almost exclusively confined to the invertebrate animals. The existence of a division of the genus Planaria, which inhabits the dry land, interested me much. These animals are of so simpl…
Darwin shifts to turkey-buzzard and Gallinazo distribution and gregarious flight behavior, then introduces fulgurites—vitrified lightning tubes—found near Maldonado and compares measurements with European geological experiments.
bird. The sealers say that the flesh of these birds, when cooked, is quite white, and very good eating; but bold must the man be who attempts such a meal. We have now only to mention the turkey-buzzard (Vultur aura), and the Gallinazo. The former is found wherever the country is moderately damp, from Cape Horn to North America. Differently from the Polyborus Brasiliensis and Chimango, it has found its way to the Falk…
Darwin records the shifting, deceptive mudbanks of Punta Alta, then searches for fossil bones, observes puma and zorillo (skunks), and describes how zorillo’s fetid oil deters attacks.
high." The only object within our view which was not level was the horizon; rushes looked like bushes unsupported in the air, and water like mud-banks, and mud-banks like water. We passed the night in Punta Alta, and I employed myself in searching for fossil bones; this point being a perfect catacomb for monsters of extinct races. The evening was perfectly calm and clear; the extreme monotony of the view gave it an…
Darwin directly challenges the claim that large animals require luxuriant vegetation, using southern Africa as an analogy and arguing that sterile landscapes can still support enormous herds.
with a luxuriant vegetation: I have no doubt that the sterile country a little southward, near the Rio Negro, with its scattered thorny trees, would support many and large quadrupeds. That large animals require a luxuriant vegetation, has been a general assumption which has passed from one work to another; but I do not hesitate to say that it is completely false, and that it has vitiated the reasoning of geologists …
Beginning his ride from Bahia Blanca to Buenos Ayres on September 18, Darwin travels through uninhabited plains, discusses the Rio Sauce and Sierra Ventana, climbs for geology, and describes cold, dangerous bivouacs.
BAHIA BLANCA TO BUENOS AYRES Set out for Buenos Ayres--Rio Sauce--Sierra Ventana--Third Posta--Driving Horses--Bolas--Partridges and Foxes--Features of the Country--Long-legged Plover--Teru-tero--Hail-storm--Natural Enclosures in the Sierra Tapalguen--Flesh of Puma--Meat Diet--Guardia del Monte--Effects of Cattle on the Vegetation--Cardoon--Buenos Ayres--Corral where Cattle are Slaughtered. SEPTEMBER 18th.--I hired…
He gives detailed observations of gossamer spiders’ behavior—web threads, aerial ascent, and possible causes like heated air—then reports that nets tow behind the Beagle yield many crustaceans and other pelagic creatures.
While watching some that were suspended by a single thread, I several times observed that the slightest breath of air bore them away out of sight, in a horizontal line. On another occasion (25th) under similar circumstances, I repeatedly observed the same kind of small spider, either when placed or having crawled on some little eminence, elevate its abdomen, send forth a thread, and then sail away horizontally, but …
Darwin discusses sparse life in deep water far offshore, limited catches near Cape Horn despite abundant whales and seabirds, and then describes mysteries of how pelagic organisms subsist based on infusoria and food chains.
animal lives in the open sea, and probably wants a place of rest, I suppose this beautiful and most anomalous structure is adapted to take hold of floating marine animals. In deep water, far from the land, the number of living creatures is extremely small: south of the latitude 35 degs., I never succeeded in catching anything besides some beroe, and a few species of minute entomostracous crustacea. In shoaler water,…
He vividly describes phosphorescent seas with glowing waves, explains it via gelatinous particles and ocean purification by decomposition, and notes similar luminance patterns at depths and near Fernando Noronha.
every wave was bright, and the sky above the horizon, from the reflected glare of these livid flames, was not so utterly obscure as over the vault of the heavens. As we proceed further southward the sea is seldom phosphorescent; and off Cape Horn I do not recollect more than once having seen it so, and then it was far from being brilliant. This circumstance probably has a close connection with the scarcity of organ…
Darwin describes his experiment with tied condors to test whether carrion-vultures find food by smell, and reviews conflicting reports from Audubon and Bachman about olfaction.
retain its vigour, between five and six weeks without eating: I cannot answer for the truth of this, but it is a cruel experiment, which very likely has been tried. When an animal is killed in the country, it is well known that the condors, like other carrion-vultures, soon gain intelligence of it, and congregate in an inexplicable manner. In most cases it must not be overlooked, that the birds have discovered their…
Darwin reports insect records from his collection: he excludes one alpine Haltica and a single Melasoma, then summarizes Waterhouse’s count of beetle species by families and remarks that individuals are scarcer than species.
would have been aided, instead of checked, by the force of gravity. The sap is concentrated by boiling, and is then called treacle, which it very much resembles in taste. We unsaddled our horses near the spring, and prepared to pass the night. The evening was fine, and the atmosphere so clear, that the masts of the vessels at anchor in the bay of Valparaiso, although no less than twenty-six geographical miles dista…
Darwin cites reports that seaweed grows extremely quickly, describing an experiment where a rock exposed only at spring tides became thickly covered with Fucus digitatus and Fucus esculentus within six months.
four pounds. The Guaso is perhaps more expert with the lazo than the Gaucho; but, from the nature of the country, he does not know the use of the bolas. August 18th.--We descended the mountain, and passed some beautiful little spots, with rivulets and fine trees. Having slept at the same hacienda as before, we rode during the two succeeding days up the valley, and passed through Quillota, which is more like a collec…
Darwin explains that his climate conclusions for Tierra del Fuego come from Capt. King and Beagle observations, and that for the Falkland Islands he uses the mean temperature of December–February derived from careful hourly readings.
been introduced in some of the simple machinery; but even to the present day, water is removed from some mines by men carrying it up the shaft in leathern bags! The labouring men work very hard. They have little time allowed for their meals, and during summer and winter they begin when it is light, and leave off at dark. They are paid one pound sterling a month, and their food is given them: this for breakfast con…
Darwin reflects on how repeated, long-term causes produce enormous geological effects, linking the roaring, rattling mountain torrents and accumulated sediments to deep time and relentless erosion.
glides past is irrevocable. So was it with these stones; the ocean is their eternity, and each note of that wild music told of one more step towards their destiny. It is not possible for the mind to comprehend, except by a slow process, any effect which is produced by a cause repeated so often, that the multiplier itself conveys an idea, not more definite than the savage implies when he points to the hairs of his he…
He introduces fringing reefs: they are narrow where land drops sharply and extend farther where slopes are gentle, and reef growth reaches only to the depth where a coral foundation within 20–30 fathoms exists.
these barrier reefs based? Why, with their wide and deep moat-like channels, do they stand so far from the included land? We shall soon see how easily these difficulties disappear. We come now to our third class of Fringing-reefs, which will require a very short notice. Where the land slopes abruptly under water, these reefs are only a few yards in width, forming a mere ribbon or fringe round the shores: where the …
Darwin proposes the subsidence-and-upward-growth model: as an island with fringing reefs sinks, coral keeps pace at the surface, converting reef structures into barrier reefs and then atolls, explaining lagoon channels and distances from shore.
[picture] classes. We have seen that we are driven to believe in the subsidence of those vast areas, interspersed with low islands, of which not one rises above the height to which the wind and waves can throw up matter, and yet are constructed by animals requiring a foundation, and that foundation to lie at no great depth. Let us then take an island surrounded by fringing-reefs, which offer no difficulty in their…
Darwin predicts that reefs should sometimes be dead and submerged in subsiding regions, describes leeward deterioration and Chagos’s partially dead atolls at 6–8 fathoms depth, and discusses how “half-drowned atolls” fit his coral-ring history.
studded, and its edge symmetrically bordered with oval basins of coral-rock just lipping the surface of the sea, sometimes clothed with vegetation, and each containing a lake of clear water! One more point in detail: as in the two neighbouring archipelagoes corals flourish in one and not in the other, and as so many conditions before enumerated must affect their existence, it would be an inexplicable fact if, during…
Darwin ascends Green Hill, notes water management and roads built for a fortress-like island, then explains volcanic bombs and describes Ascension’s Devil’s Riding School layers containing organized infusoria and plant siliceous tissues.
force, by relieving the pressure in the more central parts of the bomb, allowed the heated vapours to expand their cells, thus forming the coarse cellular mass of the centre. A hill, formed of the older series of volcanic rocks, and which has been incorrectly considered as the crater of a volcano, is remarkable from its broad, slightly hollowed, and circular summit having been filled up with many successive layers o…
Einstein’s preface explains that the book aims to make relativity understandable without advanced mathematics, assumes a university-level education, repeats ideas for clarity, and treats empirical foundations gently for non-physicists.
XXX. Cosmological Difficulties of Newton’s Theory XXXI. The Possibility of a “Finite” and yet “Unbounded” Universe XXXII. The Structure of Space According to the General Theory of Relativity Appendices: I. Simple Derivation of the Lorentz Transformation (supplementary to section XI) II. Minkowski’s Four-Dimensional Space (“World”) (supplementary to section XVII) III. The Experimental Confirmation of the General…
Einstein derives the relativistic velocity-addition formula from the Lorentz transformation and supports it with the Fizeau experiment on light propagation in flowing liquid, noting later corroboration and relation to Lorentz’s electrodynamical theory.
image014 In accordance with the principle of relativity we shall certainly have to take for granted that the propagation of light always takes place with the same velocity *w with respect to the liquid*, whether the latter is in motion with reference to other bodies or not. The velocity of light relative to the liquid and the velocity of the latter relative to the tube are thus known, and we require the velocity of …
Einstein uses Maxwell electrodynamics and energy conservation to argue that when a body absorbs radiation energy E0 without changing its velocity, its inertial mass increases by E0/c^2, yielding E=mc^2.
or, briefly, relative to every “Galileian” system of co-ordinates. In contrast to classical mechanics; the Lorentz transformation is the deciding factor in the transition from one such system to another. By means of comparatively simple considerations we are led to draw the following conclusion from these premises, in conjunction with the fundamental equations of the electrodynamics of Maxwell: A body moving with th…
Einstein argues the special theory of relativity is supported by electromagnetic experience, predicting stellar aberration and spectral-line shifts, and he cites cathode-ray/β-ray behavior and the Michelson–Morley ether-drift failure as requiring relativity.
EXPERIENCE AND THE SPECIAL THEORY OF RELATIVITY To what extent is the special theory of relativity supported by experience? This question is not easily answered for the reason already mentioned in connection with the fundamental experiment of Fizeau. The special theory of relativity has crystallised out from the Maxwell-Lorentz theory of electromagnetic phenomena. Thus all facts of experience which support the elect…
Einstein continues the experience-based case by explaining why making Galilean coordinate transformations naïvely makes Maxwell–Lorentz equations fail for moving frames, implying a physically unique inertial frame and motivating the ether-drift idea.
The second class of facts to which we have alluded has reference to the question whether or not the motion of the earth in space can be made perceptible in terrestrial experiments. We have already remarked in Before the theory of relativity was put forward, it was difficult to become reconciled to this negative result, for reasons now to be discussed. The inherited prejudices about time and space did not allow any d…
He recounts Michelson’s mirror interferometer as expected to reveal ether-drift via orientation-dependent light travel times, then explains that Lorentz–FitzGerald length contraction and relativity eliminate any detectable ether drift by removing the need for a unique preferred frame.
be assumed relative to the earth, and for a long time the efforts of physicists were devoted to attempts to detect the existence of an æther-drift at the earth’s surface. In one of the most notable of these attempts Michelson devised a method which appears as though it must be decisive. Imagine two mirrors so arranged on a rigid body that the reflecting surfaces face each other. A ray of light requires a perfectly d…
Using the equivalence principle, Einstein derives that light rays curve in gravitational fields, estimates the solar-bending angle, links this to the 1919 eclipse test, and limits the special theory’s validity to ignoring gravity.
A FEW INFERENCES FROM THE GENERAL PRINCIPLE OF RELATIVITY The considerations of Section XX show that the general principle of relativity puts us in a position to derive properties of the gravitational field in a purely theoretical manner. Let us suppose, for instance, that we know the space-time “course” for any natural process whatsoever, as regards the manner in which it takes place in the Galileian domain relativ…
Einstein argues that in general relativity the space-time continuum cannot generally be treated as Euclidean, so coordinates are assigned using Gauss coordinates without direct physical meaning, and he derives the Lorentz transformation by requiring light propagation in vacuo to keep the same form in different inertial systems.
*ds*2 = *dx*12 + *dx*22 + *dx*32 + *dx*42. is independent of the choice of the body of reference. We call the magnitude *ds* the “distance” apart of the two events or four-dimensional points. Thus, if we choose as time-variable the imaginary variable image035 instead of the real quantity *t*, we can regard the space-time contintium—accordance with the special theory of relativity—as a “Euclidean” four-dimensional…
Einstein argues that for weak fields the theory reproduces Newtonian gravity, but he explains Mercury’s perihelion precession as a relativistic effect consistent with observation, unlike classical mechanics.
interpreting the empirical law of the equality of inertial and gravitational mass; but it has also already explained a result of observation in astronomy, against which classical mechanics is powerless. If we confine the application of the theory to the case where the gravitational fields can be regarded as being weak, and in which all masses move with respect to the coordinate system with velocities which are small…
In Appendix I, Einstein derives the Lorentz transformation from light-signal propagation, relativity of measuring rods, and snapshots, first for events along the x-axis and then generally for arbitrary directions.
curved space in which the two “counter-points” are identical (indistinguishable from each other). An elliptical universe can thus be considered to some extent as a curved universe possessing central symmetry. It follows from what has been said, that closed spaces without limits are conceivable. From amongst these, the spherical space (and the elliptical) excels in its simplicity, since all points on it are equivalen…
Einstein surveys how general relativity was tested: Mercury’s perihelion advance near 43 arcseconds per century, light deflection during the 1919 solar eclipse expeditions, and gravitational redshift of spectral lines.
(*a*) Motion of the Perihelion of Mercury According to Newtonian mechanics and Newton’s law of gravitation, a planet which is revolving round the sun would describe an ellipse round the latter, or, more correctly, round the common centre of gravity of the sun and the planet. In such a system, the sun, or the common centre of gravity, lies in one of the foci of the orbital ellipse in such a manner that, in the course…
He argues democracy guides scientific study toward judging independently and valuing facts, so American science favors practical applications over abstract theory and discourages “meditation.”
Theoretical Science If a democratic state of society and democratic institutions do not stop the career of the human mind, they incontestably guide it in one direction in preference to another. Their effects, thus circumscribed, are still exceedingly great; and I trust I may be pardoned if I pause for a moment to survey them. We had occasion, in speaking of the philosophical method of the American people, to make se…
Tocqueville says democratic bustle and constant activity undermine the calm needed for deep contemplation, so higher sciences suffer, though he treats revolutions as exceptional causes.
and abstract portion of human knowledge. In this respect the Americans carry to excess a tendency which is, I think, discernible, though in a less degree, amongst all democratic nations. Nothing is more necessary to the culture of the higher sciences, or of the more elevated departments of science, than meditation; and nothing is less suited to meditation than the structure of democratic society. We do not find ther…