Observations Sentence Examples

Regular observations were made of both elements.

It never occurred to me that it might be worth while to make my own observations and describe the experiences peculiarly my own.

Still, you must have some personal observations... thoughts... feelings?

These include the mutual distances of some of the stars in the Pleiades, a few observations of the apparent diameter of the sun, others of the distance of the moon from neighbouring stars, and a great number of measurements of the diameter of the moon.

Observations have usually been limited to a portion of the year, or to a few hours of the day, whilst the results from different stations differ much in details.

The observations were usually confined to a few hours of the day, very commonly between II A.M.

In the island of Juist, off the Friesland coast, from three weeks' observations they obtained only 5.2 as the mean.

Every once in a while, the half-demon surprised him with the depth of his observations and compassion.

Gockel, have made long series of observations without it.

Annual Variation.-When observations are made at irregular hours, or at only one or two fixed hours, it is doubtful how representative they are.

Observations on the Sonnblick agree with those at low-level stations in showing a diminution of dissipation with increase of relative humidity.

On the other hand, at Altjoch, an Alpine station, from nine days' observations in July 1903 they obtained a mean of 137, the maximum being 224, and the minimum 92.

Some sensible observations by the editor were added to the original biography.

This will turbocharge science, which will no longer rely exclusively on slow observations in real time.

The earliest Arabian traveller whose observations have come down to us is the merchant Sulaiman, who embarked in the Persian Gulf and made several voyages to India and China, in the middle of the 9th century.

The Observations of Sir Richard Hawkins in his Voyage into the South Sea, published in 1622, are very valuable.

He started once more in December 1771, and at length reached the Coppermine river, which he surveyed to its mouth, but his observations are unreliable.

The motions of the earth as a planet must be taken into account, as they render possible the determination of position and direction by observations of the heavenly bodies.

The most careful observations are those by Fiirbringer.

His mind was as well cultivated as his bodily powers; he wrote well, and his observations are generally acute and accurate; he was brave, kindly and generous.

The rainfall on the summit is heavy, 72.14 inches a year being the average of twelve years' observations.

By the adoption of a regular system of work, and a careful plan of reduction, he was able to keep his observations reduced practically up to date, and published them annually with a degree of punctuality which astonished his contemporaries.

He remodelled the volumes of observations, put the library on a proper footing, mounted the new (Sheepshanks) equatorial and organized a new magnetic observatory.

In 1847 an altazimuth was erected, designed by Airy to enable observations of the moon to be made not only on the meridian, but whenever she might be visible.

This value, although considerably in excess of that previously found by different methods, was held by Airy, from the care and completeness with which the observations were carried out and discussed, to be "entitled to compete with the others on, at least, equal terms."

All patent logs have errors, the amounts of which should be ascertained by shore observations when passing a well surveyed coast in tideless waters on a calm day.

A Log Book is a marine or sea journal, containing, in the British navy, the speed, course, leeway, direction and force of the wind, state of the weather, and barometric and thermometric observations.

In 1752 he published an Essai d'une nouvelle theorie sur la resistance des / g uides, which contains a large number of original ideas and new observations.

The inspector, after making his investigation, is required to make a report to the Board of Trade as to the causes of the accident and the circumstances attending the same, with any observations on the subject which he deems right, and the Board " shall cause every such report to be made public in such manner as they think expedient."

The indicated horse-power developed by a cylinder may always be ascertained from an indicator diagram and observations of the speed.

No biological generalization rests on a wider series of observations, or has been subjected to a more critical scrutiny than that every living organism has come into existence from a living portion or portions of a pre-existing organism.

No serious observer, acquainted with modern microscopic technical methods, has been able to confirm the explanation of their observations.

Westermarck has shown from his observations in Morocco that the blood of the victim was considered to visit a curse upon the object to whom the sacrifice is offered and thereby the latter is made amenable to the sacrificer.

History had always been a favourite study with him, and Mably's Observations sur l'histoire appears to have had considerable influence in determining him to the choice of some special period for historic research.

This theory Gibbon completely exploded in his Critical Observations (1770) - no very difficult task, indeed, but achieved in a style, and with a profusion of learning, which called forth the warmest commendations both at home and abroad.

He arranges a selection from his observations on the nebulae in such a way as to give great plausibility to his view of the gradual transmutation of nebulae into stars Herschel begins by showing us that there are regions in the heavens where a faint diffused nebulosity is all that can be detected by the telescope.

On the 6th of November in that year he plainly saw the living parasites under the microscope in the blood of a malarial patient, and he shortly afterwards communicated his observations to the Paris Academie de Medecine.

This deduction harmonized the observations of Andrews and of Hess previously alluded to, and also accounted satisfactorily for the Law of Thermoneutrality.

When her brother accepted the office of astronomer to George III., she became his constant assistant in his observations, and also executed the laborious calculations which were connected with them.

In 1797 she presented to the Royal Society an Index to Flamsteed's observations, together with a catalogue of 561 stars accidentally omitted from the "British Catalogue," and a list of the errata in that publication.

Thompson, From the Cotton Field to the Cotton Mill, a Study of the Industrial Transition in North Carolina (New York, 1906), contains some interesting observations on the changes in social conditions resulting from the growth of the cotton-manufacturing industry.

His observations of the great comet of January 1672 supplied the basis of modern cometary astronomy.

One view of the origin of the latter (largely based upon observations upon the development of Polygordius) sees in the blood system a persistent blastocoel.

The records of Delisle's observations at St Petersburg are preserved in manuscript at the Pulkowa observatory.

In 1639 he accompanied Pedro Texiera in his second exploration of the Amazon, in order to take scientific observations, and draw up a report for the Spanish government.

His remarks on horses, cattle, &c., are not less interesting; and there is a very good account of the diseases of each species, and some just observations on the advantage of mixing different kinds on the same pasture.

Norden's work contains many judicious observations on the " different natures of grounds, how they may be employed, how they may be bettered, reformed and amended."

In Clausilia, according to the observations of C. Gegenbaur, the primitive shell-sac does not flatten out and disappear, but takes the form of a flattened closed sac. Within this closed sac a plate of calcareous matter is developed, and after a time the upper wall of the sac disappears, and the calcareous plate continues to grow as the nucleus of the permanent shell.

The external form of the embryo goes through the same changes as in other Gastropods, and is not, as was held previously to Lankester's observations, exceptional.

Hence his work, written in French, contains a far greater amount of original matter; and his personal observations made in many countries, from England to Egypt, enabled him to avoid most of the puerilities which disfigure other works of his own or of a preceding age.

Most of the birds he describes are characterized with accuracy sufficient to enable them to be identified, and his observations upon them have still some interest; but he was innocent of any methodical system, and was not exempt from most of the professional fallacies of his time.'

Observations on birds form the principal though by no means the whole theme of this book, which may be safely said to have done more to promote a love of ornithology in England than any other work that has been written, nay more than all the other works (except one next to be mentioned) put together.

The views of neither of these systematizers pleased Temminck, who in 1817 replied rather sharply to Vieillot in some Observations sur la classification methodique des oiseaux, a pamphlet published at Amsterdam, and prefixed to the second edition m i nd.

As regards the struthious birds, they could not be likened to the duck, for in them at no age was there any indication of a single median centre of ossification, as Geoffroy had satisfied himself by his own observations made in Egypt many years before.

Cuvier seems to have acquiesced in the corrections of his views made by Geoffroy, and attempted no rejoinder; but the attentive and impartial student of the discussion will see that a good deal was really wanting to make the latter's reply effective, though, as events have shown, the former was hasty in the conclusions at which he arrived, having trusted too much to the first appearance of centres of ossification, for, had his observations in regard to other birds been carried on with the same attention to detail as in regard to the fowl, he would certainly have reached some very different results.

By way of examples of L'Herminier's observations, what he says of the two groups that had been the subject of Cuvier's and the elder Geoff roy's contest may be mentioned.

While furnishing - almost unconsciously, however - additional evidence for overthrowing that classification, there is, nevertheless, no attempt made to construct a better one; and the elaborate tables of dimensions, both absolute and proportional, suggestive as is the whole tendency of the author's observations, seem not to lead to any very practical result, though the systematist's need to look beneath the integument, even in parts that are so comparatively little hidden as birds' feet, is once more made beyond all question apparent.

Carrying on the work from the anatomical point at which he had left it, correcting his errors, and utilizing to the fullest extent the observations of Keyserling and Blasius, to which reference has already been made, Muller, though hampered by mistaken notions of which he seems to have been unable to rid himself, propounded a scheme for the classification of this group, the general truth of which has been admitted by all his successors, based, as the title of his treatise expressed, on the hitherto unknown different types of the vocal organs in the Passerines.

In the evolution of these laws Dr Cornay had most laudably studied, as his observations prove, a vast number of different types, and the upshot of his whole labours, though not very clearly stated, was such as to wholly subvert the classification at that time generally adopted by French ornithologists.

Blanchard published some Recherches sur les caracteres osteo- logiques des oiseaux appliquees a la classification naturelle de ces animaux, strongly urging the superiority of such characters over those drawn from the bill or feet, which, he remarks, though they may have sometimes given correct notions, have mostly led to mistakes, and, if observations of habits and food have sometimes afforded happy results, they have often been deceptive; so that, should more be wanted than to draw up a mere inventory of creation or trace the distinctive outline of each species, zoology without anatomy would remain a barren study.

Newton accepted the three subclasses of Huxley, Saururae, Ratitae and Carinitae, and made a series of cautious but critical observations on the minor divisions of the Carinates.

Oberlin published several manuals on archaeology and ancient geography, and made frequent excursions into different provinces of France to investigate antiquarian remains and study provincial dialects, the result appearing in Essai sur le patois Lorrain (1775); Dissertations sur les Minnesingers (1782-1789); and Observations concernant le patois et les mceurs des gens de la campagne (1791).

Swammerdam's Biblia naturae, issued in 1737, fifty years after its author's death, and containing observations on the structure and lifehistory of a series of insect types.

His chief books on chemistry were six volumes of Experiments and Observations on different Kinds of Air, published between 1774 and 1786; Experiments on the Generation of Air from Water (1793) Experiments and Observations relating to the Analysis of Atmospheric Air, and Considerations on the Doctrine of Phlogiston established and that of the Composition of Water refuted (1800).

It has been pointed out that the cavity of the sacs corresponds in many particulars with the coelom of higher animals, and in Lebidinsky's observations on the development there is some support to the view that a coelom exists.

The book, as it stands, is a collection of the discourses, observations and aphorisms of a sage called Koheleth, a term the precise meaning of which is not certain.

This general view is set forth in a number of particular observations.

But it is more probable that we have it in the form in which it grew up - a series of observations by the original author with interspersed editorial remarks; and it is better to preserve the existing form as giving a record of the process of growth.

Wallace notes the resemblance which he traced between the Malays and the Mongolians, and others have recorded similar observations as to the physical appearance of the two races.

He was especially interested in questions relating to the polarization of light, and his observations in this field, which gained him the Rumford medal of the Royal Society in 1840, laid the foundations of the polarimetric analysis of sugar.

The first step in this direction was effected by the co-ordination of Gay Lussac's observations on the combining volumes of gases.

The solution came abOut by arranging the elements in the order of their atomic weights, tempering the arrangement with the results deduced from the theory of valencies and experimental observations.

Vauquelin in 1797, and Klaproth's investigation of tellurium in 1798, the next important series of observations was concerned with platinum and the allied metals.

Balard discovered chlorine monoxide in 1834, investigating its properties and reactions; and his observations on hypochlorous acid and hypochlorites led him to conclude that " bleaching-powder " or " chloride of lime " was a compound or mixture in equimolecular proportions of calcium chloride and hypochlorite, with a little calcium hydrate.

The purity of the compounds thus obtained is checked by spectroscopic observations.

Dumas went no further that thus epitomizing his observations; and the next development was made in 1836 by Auguste Laurent, who, having amplified and discussed the applicability of Dumas' views, promulgated his Nucleus Theory, which assumed the existence of " original nuclei or radicals " (radicaux or noyaux fondamentaux) composed of carbon and hydrogen, and " derived nuclei " (radicaux or noyaux derives) formed from the original nuclei by the substitution of hydrogen or the addition of other elements, and having properties closely related to the primary nuclei.

These observations may be summarized by saying that the benzene nucleus is more negative in character than the aliphatic residues.

More important are Kekule's observations that nitrous acid oxidizes pyrocatechol or [I.2]-dioxybenzene, and protocatechuic acid or [3.4]- dioxybenzoic acid to dioxytartaric acid, (C(OH) 2 COOH) 2 (Ann., 1883, 221, p. 230); and 0.

But, at the same time, the constants in the above relation are not identical with those in the corresponding relation empirically deduced from observations on fatty hydrocarbons; and we are therefore led to conclude that a benzene union is considerably more stable than an ethylene union.

Bamberger's observations on reduced quinoline derivatives point to the same conclusion, that condensed nuclei are not benzenoid, but possess an individual character, which breaks down, however, when the molecule is reduced.

We may, however, notice Heinrich Rose i and Friedrich WShler, 2 who, having worked up the results of their teacher Berzelius, and combined them with their own valuable observations, exerted great influence on the progress of analytical chemistry by publishing works which contained admirable accounts of the then known methods of analysis.

A physicist, however, does more than merely quantitatively determine specific properties of matter; he endeavours to establish mathematical laws which co-ordinate his observations, and in many cases the equations expressing such laws contain functions or terms which pertain solely to the chemical composition of matter.

According to the law of Avogadro, equal volumes of different gases under the same conditions of temperature and pressure contain equal numbers of molecules; therefore, since the density depends upon the number of molecules present in unit volume, it follows that for a comparison of the densities of gases, the determinations must be made under coincident conditions, or the observations reduced or re-computed for coincident conditions.

By actual observations it has been shown that ether, alcohol, many esters of the normal alcohols and fatty acids, benzene, and its halogen substitution products, have critical constants agreeing with this originally empirical law, due to Sydney Young and Thomas; acetic acid behaves abnormally, pointing to associated molecules at the critical point.

Their observations on the solid elements led to a remarkable generalization, now known as Dulong and Petit's law.

Nilson and Pettersson's observations on beryllium and germanium have shown that the atomic heats of these metals increase with rise of temperature, finally becoming constant with a value 5.6.

Neumann, who, in 1831, deduced from observations on many carbonates (calcium, magnesium, ferrous, zinc, barium and lead) that stoichiometric quantities (equimolecular weights) of compounds possess the same heat capacity.

Regnault confirmed Neumann's observations, and showed that the molecular heat depended on the number of atoms present, equiatomic compounds having the same molecular heat.

Kopp systematized the earlier observations, and, having made many others, he was able to show that the molecular heat was an additive property, i.e.

Laplace is due the theoretical proof that this function is independent of temperature and pressure, and apparent experimental confirmation was provided by Biot and Arago's, and by Dulong's observations on gases and vapours.

The subject was next taken up by Hans Landolt, who, from an immense number of observations, supported in a general way the formula of Gladstone and Dale.

These observations admit of ready explanation in the following manner.

Isomorphism is most clearly discerned between elements of analogous chemical properties; and from the wide generality of such observations attempts have been made to form a classification of elements based on isomorphous replacements.

According to observations extending from 1706 to 1899, the mean day of the freezing of the Neva is November 25th, the earliest October 28th, the latest January 9th, and the next latest December 26th.

These materials generally include reconnaissance survey of small districts, route surveys and astronomical observations supplied by travellers, and information obtained from native sources.

On the other hand he unwisely rejected the results of the observations for latitude made by Pytheas in 326 B.C. at his native town, Massilia, and during a subsequent voyage to northern Europe.

He moreover accuses Eratosthenes, (whose determination of a degree he accepts without hesitation) with trusting too much to hypothesis in compiling his map instead of having recourse to latitudes and longitudes deduced by astronomical observations.

Such observations, however, were but rarely available at the time.

In biological chemistry he worked at the problems of animal heat and at the phenomena accompanying the growth of plants, and he also devoted much time to meteorological questions and observations.

He is best known by the five volumes of Medical Inquiries and Observations, which he brought out 'at intervals from 1789 to 1798 (two later editions revised by the author).

In 1776 it was moved in the House of Commons by David Hartley, son of the author of Observations on Man, that " the slave trade was contrary to the laws of God and the rights of men "; but this motion - the first which was made on the subject - failed.

Furthermore, the observations on American wasps render it probable that the earlier accounts of the instinctive behaviour of such wasps are exaggerated.

But the Peckhams' careful observations and experiments show that, with the American wasps, the victims stored in the nests are quite as often dead as alive; that those which are only paralysed live for a varying number of days, some more, some less; that wasp larvae thrive just as well on dead victims, sometimes dried up, sometimes undergoing decomposition, as on living and paralysed prey; that the nerve-centres are not stung with the supposed uniformity; and that in some cases paralysis, in others death, follows when the victims are stung in parts far removed from any nerve-centre.

Observations in temperature and salinity have only been taken during summer.

From 1881 till 1904 meteorological observations were taken from the summit of Ben Nevis, the observers at first making the ascent daily for the purpose.

In a series of observations of winds about one half have been found to indicate a direction from north-east or east.

It is thought better here, for the sake of clearness, to reserve observations on revenues specially assigned to the international administration of the Ottoman Public Debt, and on the expenditure of that administration, and to deal with that subject separately, while, however, including the total figures of both in the general figures in order to reproduce exactly the totals shown in the budget of the empire.

Given that such observations at the surface of the sea, at intermediate levels and at the bottom are sufficiently numerous and are of a high degree of precision, general conclusions as to the movements of the ocean may be deduced from established theorems in hydrodynamics.

At the same time temperature observations are made.

Climatological Atlas of the Russian Empire, by the Physical Observatory (St Petersburg, 1900), gives data and observations covering the period 1849-1899.

This observatory, the foundations of which were fixed in the snow that appears to cover the summit to a depth of ten metres, was built in September 1893, and Janssen, in spite of his sixty-nine years, made the ascent and spent four days taking observations.

Mention should also be made of a third method which has hardly yet been tried, namely, that of endeavouring to isolate one of the three "directions" by the method of suggestion or even hypnotic trance observations.

Transits of Venus and observations of Deterrnina- various kinds on Mars are all to be included in this tion.

No purely astronomical enterprise was ever carried out on so Transits of P large a scale or at so great an expenditure of money and labour as was devoted to the observations of these transits, and for several years before their occurrence the astronomers of every leading nation were busy in discussing methods of observation and working out the multifarious details necessary to their successful application.

These four nations sent out well-equipped expeditions to various quarters of the globe, both in 1874 and 1882, to make the required observations; but when the results were discussed they were found to be extremely unsatisfactory.

It had been supposed that, with the greatly improved telescopes of modern times, contact observations could be made with much greater precision than in 1761 and 1769, yet, for some reason which it is not easy to explain completely, the modern observations were but little better than the older ones.

The photographs led to no more definite result than the observations of contacts, except perhaps those taken by the Americans, who had adopted a more complete system than the Europeans; but even these were by no means satisfactory.

The combined result from both these methods is 8.857", while the combination of all the contact observations made by all the parties gave the much smaller result, 8.794".

The failure of the method based on transits of Venus led to an international effort carried out on the initiative of Sir David Gill to measure the parallax by observations on those minor planets which approach nearest the earth.

The scheme of observations was organized on an extended scale.

The drawback of greater distance was, however, in Gill's opinion, more than compensated by the accuracy with which the observations could be made.

From the meridian observations of the same planets made for the purpose of controlling the elements of motion of the planets Auwers found it = 8.806".

Serious doubt was first cast upon its accuracy by the observations of Nyren with the same instrument during the years 1880-1882, but on a much larger number of stars.

His result, from his observations alone, was 20.52"; and taking into account the other Puikowa results, he concluded the most probable value to be 20.492".

In 1895 Chandler, from a general discussion of all the observations, derived the value of 20.50".

Meridian observations of the moon have been heretofore made by observing the transit of its illuminated limb.

In each case the results of the observations may be systematically in error, not only from the uncertain diameter of the moon, but in a still greater degree from the varying effect of irradiation and the personal equation of the observers.

In a refined form this method is often employed for measuring the intensity of a magnetic field at a given place, just as the intensity of gravity at different parts of the earth is deduced from observations of the rate at which a pendulum of known length vibrates.

Thomson (afterwards Lord Kelvin) in 1847, as the result of a mathematical investigation undertaken to explain Faraday's experimental observations.

These observations have an important bearing upon the molecular theory of magnetism, which will be referred to later.

Two sets of observations are taken, one when the blocks are fixed at the ends of the bars, and another when they are nearer together, the clear length of the bars.

Two groups of observations were recorded, one giving the induction in the inner coil and the other that in the outer coil.

Magnetization In Very Weak Fields Some interesting, observations have been made of the effects produced by very small magnetic forces.

According to Joule's observations, the length of a bar of iron or soft steel was increased by magnetization, the elongation being proportional up to a certain point to the square of the intensity of magnetization; but when the " saturation point " was approached the elongation was less than this law would require, and a stage was finally reached at which further increase of the magnetizing force produced little or no effect upon the length.

Taylor Jones showed in 1897 that only a small proportion of the contraction exhibited by a nickel wire when magnetized could be accounted for on Kirchhoff's theory from the observed effects of pulling stress upon magnetization; and in a more extended series of observations Nagaoka and Honda found wide quantitative divergences between the results of experiment and calculation, though in nearly all cases there was agreement as to quality.

Thomson, who, from the results of Bidwell's observations on the magnetic deformation of cobalt, was led to expect that that metal would exhibit a reversal opposite in character to the effect observed in iron.

It would hardly be safe to generalize from these observations; the effects may possibly be dependent upon the physical condition of the metals.

These observations have been verified and extended by Knott, whose researches have brought to light a large number of additional facts, all of which are in perfect harmony with Maxwell's explanation of the twist.

These last observations are, however, regarded as uncertain.

Morris's results for iron, and gives some additional observations for steel, nickel and cobalt.

Similar observations were made by Laurie (17) in Lankester's laboratory (1890) with regard to the early condition of the coxal gland of Scorpio, and by Bertkau (41) as to that of the spider Atypus.

In a year and a half the cubs attain their full development; and from observations on captive specimens it appears that the duration of life ought to extend to some thirteen or fourteen years.

An appeal made by Miller for observations on the development of the Caeciliae, and of those Amphibia which retain gills or gill-clefts throughout life, has unfortunately yielded no fruits.

Under the influence of the touchstone of strict inquiry set on foot by the Royal Society, the marvels of witchcraft, sympathetic powders and other relics of medieval superstition disappeared like a mist before the sun, whilst accurate observations and demonstrations of a host of new wonders accumulated, amongst which were numerous contributions to the anatomy of animals, and none perhaps more noteworthy than the observations, made by the aid of microscopes constructed by himself, of Leeuwenhoek, the Dutch naturalist (1683), some of whose instruments were presented by him to the society.

It is one of Darwin's great merits to have made use of these observations and to have formulated their results to a large extent as the laws of variation and heredity.

His true greatness can only be estimated by a consideration of the fact that he was a great teacher not only of human and comparative anatomy and zoology but also of physiology, and that nearly all the most distinguished German zoologists and physiologists of the period 1850 to 1870 were his pupils and acknowledged his leadership. The most striking feature about Johann Miller's work, apart from the comprehensiveness of his point of view, in which he added to the anatomical and morphological ideas of Cuvier a consideration of physiology, embryology and microscopic structure, was the extraordinary accuracy, facility and completeness of his recorded observations.

Mendel's observations constitute an ingenious attempt to throw light on the matter, and in the opinion of some biologists have led to the discovery of an important principle.

It has been maintained that this tendency to a severance of the hybrid stock into its components must favour the persistence of a new character of large volume suddenly appearing in a stock, and the observations of Mendel have been held to favour in this way the views of those who hold that the variations upon which natural selection has acted in the production of new species are not small variations but large and " discontinuous."

It is true that in 1823 Fraunhofer, inspired by his observations upon gratings, had very nearly hit the mark.'

In another respect the observations of Fraunhofer appear at first sight to be in disaccord with theory; for his measures of the diameters of the red rings, visible when white light was employed, correspond with the law applicable to dark rings, and not to the different law applicable to the luminous maxima.

Verdet's own observations, conducted with great care, fully confirm this view, and exhibit a complete agreement with theory.

The principle gives an instantaneous solution of the question of the ultimate optical efficienc y in the method of " mirror-reading," as commonly practised in various physical observations.

The above observations relate to transmitted light, but Fraunhofer extended his inquiry to the light reflected.

The position of the middle of the bright band representative of a mathematical line can be fixed with a spider-line micrometer within a small fraction of the width of the band, just as the accuracy of astronomical observations far transcends the separating power of the instrument.

Primary, secondary and spurious bows were formed, and their radii measured; a comparison of these observations exhibited agreement with Airy's analytical values.

These observations have been verified in the rabbit, mouse, fowl, guinea-pig and cat by Davidsohn, occasionally in the dog by Lubarsch; and confirmatory observations have also been made by Czerny and Maximoff.

The most valuable intellectual possession was a large mass of recorded observations in individual cases and epidemics of disease.

Whether these observations were systematic or individual, and how they were recorded, are points of which we are quite ignorant, as the theory that the votive tablets in the temples supplied such materials must be abandoned.

The first of these works is the Compendium medicinae, also called Laurea or Rosa anglicana, of Gilbert (Gilbertus Anglicus, about 1290), said to contain good observations on leprosy.

He shared and defended many of Sydenham's principles, and in the few medical observations he has left shows himself to be even more thorough-going than the "English Hippocrates."

His works contain, however, many original experiments, and excellent practical observations.

The Swiss physician, Theophile Bonet (1620-1689) had published his Sepulcretum in 1679; and observations of post mortem appearances had been made by Montanus, P. Tulp, Raymond Vieussens, A.M.

In order to select remedies which should fulfil the indication of producing symptoms like those of the disease, Hahnemann made many observations of the action of drugs on healthy persons.

His work, entitled Observations on the Diseases of an Army, was translated into many European languages and became the standard authority on the subject.

Among the most ardent of his followers was Francois Joseph Victor Broussais (1772-1838), whose theoretical views, partly founded on those of Brown and partly on the so-called vitalist school of Theophile Bordeu (1722-1776) and Paul Joseph Barthez (1734-1806), differed from these essentially in being avowedly based on anatomical observations.

Starting from these men arose a school of physicians who endeavoured to give to the study of symptoms the same precision as belonged to anatomical observations, and by the combination of both methods made a new era in clinical medicine.

No aid to the trained eye was necessary for such observations, and for many other such; yet, if we take Sir Thomas Watson (1792-1882) as a modern Sydenham, we may find in his lectures no suspicion that there may be a palsy of muscular co-ordination apart from deprivation of strength.

The comparison of observations in various climates and peoples has had some weight; while in the better knowledge of their causes their treatment has found permanent advantage.

On the one hand he worked out the general theory of the magnetic circuit in the dynamo (in conjunction with his brother Edward), and the theory of alternating currents, and conducted a long series of observations on the phenomena attending magnetization in iron, nickel and the curious alloys of the two which can exist both in a magnetic and non-magnetic state at the same temperature.

There is a set of Annual Bills from 1658 (with the exception of the years 1756 to 1764) in the library of the British Museum.3 These bills were not analysed and general results obtained from them until 1662, when Captain John Graunt first published his valuable Natural and Political Observations upon the Bills of 1 In a valuable paper on " The Population of Old London" in Blackwood's Magazine for April 1891.

Owing to the physical changes produced in the material exposed prolonged observations of temperature are impossible.

Little is known of the ministry of Angad except that he committed to writing much of what he had heard about Guru Nanak as well as some devotional observations of his own, which were afterwards incorporated in the Granth.

In 1776 appeared his (anonymous) pamphlet on the American revolution in opposition to Dr Price's Observations on the Nature of Civil Liberty, in which he sympathized with the views of the British legislature.

It is probable that the first collection of astronomical observations and terrestrial omens was made for a library established by Sargon.

The stars had been numbered and named at an early date, and we possess tables of lunar longitudes and observations of the phases of Venus.

Observations made at the most diverse parts of the globe, and the general distribution area of the disease, show that mere questions of elevation, or even configuration of the ground, have little or no influence.

On the other hand, the same observations go to show that the disease is met with oftener on the more recent formations than the older, and this fact, so far as concerns the physical characters of the soil, is identical with the questions of permeability to air and water.

Besides giving to the world the first accurate description of the holy city and the Haj ceremonies, he was the first to fix the position of Mecca by astronomical observations, and to describe the physical character of its surroundings.

The general level of the Nafud was found by Huber's observations to be about 3000 ft.

From observations made at Sana by Manzoni, Defiers and Glaser, the mean temperature for the year of that city at an altitude of 7300 ft.

His observations led him to the view that a glacier is an imperfect fluid or a viscous body which is urged down slopes of a certain inclination by the mutual pressure of its parts, and involved him in some controversy with Tyndall and others both as to priority and to scientific principle.

Forbes was also interested in geology, and published memoirs on the thermal springs of the Pyrenees, on the extinct volcanoes of the Vivarais (Ardeche), on the geology of the Cuchullin and Eildon hills, &c. In addition to about 150 scientific papers, he wrote Travels through the Alps of Savoy and Other Parts of the Pennine Chain, with Observations on the Phenomena of Glaciers (1843); Norway and its Glaciers (1853); Occasional Papers on the Theory of Glaciers (1859); A Tour of Mont Blanc and Monte Rosa (1855).

By subsequent journeys in Hungary, Transylvania, Italy, Sicily, France and Germany he extended his knowledge of volcanic phenomena; and in 1826 the results of his observations were given in a work entitled A Description of Active and Extinct Volcanos (2nd ed., 1848).

The result of this would be seen in the motions of the planets around the sun; but the most refined observations show no such effect.

Astronomical observations extend over too brief a period of time to show any attraction between different stars except those in each other's neighbourhood.

From an investigation of all the observations upon Mercury and the other three interior planets, Simon Newcomb found it almost out of the question that any such mass of matter could exist without changing either the figure of the sun itself or the motion of the planes of the orbits of either Mercury or Venus.

The qualification " almost " is necessary because so complex a system of actions comes into play, and accurate observations have extended through so short a period, that the proof cannot be regarded as absolute.

But the combination of observations and theory on which this is based is not sufficient fully to establish so slight a motion.

He was the first correctly to solve Aristotle's problem, stated above, and to apply it practically to solar observations in a darkened room (Cosmographia, 1 535).

Moestlin and his pupil Kepler - the latter applying it in 1607 to the observation of a transit of Mercury - also by Johann Fabricius, in 1611, for the first observations of sun-spots.

Nothing is said about the use of a lens or of solar observations.

He notes the convenience of the method for solar observations and its previous use by some of the observers already mentioned, as well as its advantages for easily and accurately copying on an enlarged or reduced scale, especially for chorographical or topographical documents.

The first to take up the camera obscura after Porta was Kepler, who used it in the old way for solar observations in 1600, and in his Ad Vitellionem Paralipomena (1604) discusses the early problems of the passages of light through small apertures, and the rationale of the simple dark chamber.

In 1611 Johann Fabricius published his observations of sun-spots and describes how he and his father fell back upon the old method of projecting the sun's image in a darkened room, finding that they could observe the spots just as well as with the telescope.

It was the brilliant exhibition in November 1833 that, in modern times particularly, attracted earnest students to investigate the subject of meteors generally, and to make systematic observations of their apparitions on ordinary nights of the year.

More than a thousand observations in duplicate have been made of the paths of identical meteors seen from two stations many miles apart.

These pairs of observations have shown a parallax from which the elevation of the objects above the earth, the lengths and directions of their courses, &c. could be computed.

The real velocities derived from good observations are rarely, if ever, under 7 or 8 m.

It has been abundantly demonstrated by careful observations that the east coasts of Japan are slowly rising.

At the most important stations observations are taken everyhour; at the less important, six observations daily; and at the least important, three observations.

At first an apothecary, he turned his attention to astronomy, and in 1826 commenced his observations on sun-spots.

He was the first to employ mercury for the air-pump, and devised a method of determining longitude at sea by observations of the moon among the stars.

In the Observations sur les ecrits modernes (1735-1743) Desfontaines held the gates of Philistia for eight years against the Encyclopaedists, and even the redoubtable Voltaire himself.

Among the contributors of Freron was another manufacturer of criticism, the abbe de la Porte, who, having quarrelled with his confrere, founded Observations sur la litterature moderne (1749-1752) and L'Observateur litteraire (1758-1761).

The Gundlingiana of the latter person, published at Halle (1715-1732), and written partly in Latin and partly in German by the editor, contained a miscellaneous collection of juridical, historical and theological observations and dissertations.

In addition, taking advantage of the accuracy with which the bolometer can determine the position of a source of heat by which it is affected, he mapped out in this infra-red spectrum over 700 dark lines or bands resembling the Fraunhofer lines of the visible spectrum, with a probable accuracy equal to that of refined astronomical observations.

But when we come to study his observations on the natural history of disease as presented in the living subject, we recognize at once the presence of a great clinical physician.

Villele, who before the promulgation of the charter had written some Observations sur le projet de constitution opposing it, as too democratic in character, naturally took his place on the extreme right with the ultra-royalists.

There has also been a certain amount of geographical sketching combined with trigonometrical observations; and there are the route surveys of native explorers.

It is believed to have been in use from the very time of its origin; for the observations of eclipses which were collected in Chaldaea by Callisthenes, the general of Alexander, and transmitted by him to Aristotle, were for the greater part referred to the beginning of the reign of Nabonassar, founder of the kingdom of the Babylonians.

His work also included observations on putrefaction and fermentation, which he spoke of as sisters, on the nature of salts, and on the preparation of pure metals.

Considering the accuracy of these measures (an accuracy far surpassing that of any other contemporary observations), it is somewhat surprising that this form of micrometer was never systematically used in any sustained or important astronomical researches, although a number of instruments of the kind were made by Dollond.

In observations of position angle one of the two tablets 81 can be used to record the readings.

A series of observations can be easily and more accurately accomplished with the Cape heliometer in half an hour; with the Oxford heliometer it would occupy 2 hours, and with the 4-in.

Heliometer observations of distance in their most refined sense cannot be considered absolute measures of angles.

Of course, for many purposes, mean conditions may be adopted and mean scale-values be found which are applicable with considerable pre cision to small angles or to comparatively crude observations of large distances; but the highest refinement is lost unless means are provided for determining the scale-value for each observer at each epoch of observation.

In recent times, especially since the rapid increase in the study of the exact sciences during the 19th century, observations at sea with accurate instruments have become common, and the ships' logs of to-day are provided with headings for entering daily observations of the phenomena of the seasurface.

By 1904 more than 6800 of these meteorological logs with 7,000,000 observations had been accumulated by the Meteorological Office in London; 20,000 with io,600,000 observations by the German Marine Observatory at Hamburg; 4700 with 3,300,000 observations by the Central Institute of the Netherlands at de Bilt near Utrecht.

While the sailors' logs supply the greater part of the scientific evidence available for the study of the surface phenomena of the ocean, they have been supplemented by the records of numerous scientific expeditions and latterly by publications embodying systematic observations on a permanent basis.

Valuable observations were made in oceanography during the expeditions of Captain James Cook and the polar explorers, especially those of Sir John Ross in the north and Sir James Ross in the south, but the voyage of H.M.S.

During Nansen's expedition on the " Fram " in 1894-1895, Scott Hansen made observations with a Sterneck's half-seconds pendulum on the ice where the sea was more than 1600 fathoms deep and found only an insignificant deviation from the number of swings corresponding to a normal ellipsoid.

The existence of the latter, which extends to the African continent, was announced by Sir Wyville Thomson in 1876 as a result of his discussion of the deep-sea temperature observations of the " Challenger " expedition, though the fact was not confirmed by soundings until many years later.

Unfortunately no observations of evaporation from the surface of the open sea have been made and very few comparisons of the evaporation of salt and fresh water are on record.

The fact that sea-water does evaporate more slowly than fresh water has been proved by the observations of Mazelle at Triest and of Okado in Azino (Japan).

Mill has shown that in the North Sea off the Firth of Forth the average depth of visibility of a disk in the winter half-year was 4; fathoms and in the summer half-year 62 fathoms, and, although the greater frequency of rough weather in winter might tend to obscure the effect, individual observations made it plain that the angle of the sun was the main factor in increasing the depth to which the disk remained visible.

There are some observations on the transparency of sea-water of an entirely different character.

Schott gives the following as the result of measurements of transparency by means of a white disk at 23 stations in the open ocean, where quantitative observations of the plankton under i square metre of surface were made at the same time.

Observations with the xanthometer have not hitherto been numerous, but it appears that the purest blue (o--I on Forel's scale) is found in the Sargasso Sea, in the North Atlantic and in similarly situated tropical or subtropical regions in the Indian and Pacific Oceans.

The observations made on the " Challenger " and " Gazelle," though enabling some perfectly sound general conclusions to be drawn, require to be supplemented.

Since 1870 thermometers on this principle have been in use for regular observations at German coast and light-ship stations.

We are still ignorant of the depth to.which the annual temperature wave penetrates in the open ocean, but observations in the Mediterranean enable us to form some opinion on the matter.

The observations of Aime in 1845 and of Semmola in the Gulf of Naples in 1881 show that the surface water in winter cools until the whole mass of water from the surface to the bottom, in 1600 fathoms or more, assumes the same temperature.

As the Arctic Basin is shut off from the North Atlantic by ridges rising to within 300 fathoms of the surface and from the Pacific by the shallow shelf of the Bering Sea, and as the ice-laden East Greenland and Labrador currents consist of fresh surface water which cannot appreciably influence the underlying mass, the Arctic region has no practical effect upon the bottom temperature of the three great oceans, which is entirely dominated by the influence of the Antarctic. The existence of deep-lying and extensive rises or ridges in high southern latitudes has been indicated by the deep-sea temperature observations of Antarctic expeditions.

Although observations on marine currents were made near land or between islands even in antiquity, accurate observations on the high seas have only been possible since chronometers furnished a practicable method of determining longitude, i.e.

Direct observations of currents in the open sea are difficult, and even when the ship is anchored the veering and rolling of the vessel produce disturbances that greatly affect the result.

Benjamin Franklin in 1775 and Charles Blagden in 1781, by means of numerous observations of temperature made on board the packets plying on the Atlantic passage, determined the boundaries of these two currents and their seasonal variations with considerable precision.

Bjerknes have been usefully applied in many cases, but they cannot take the place of direct observations of currents and of the fundamental processes and conditions underlying them.

Richard, L'Oceanographie (Paris, 1907); List of Oceanic Depths and Serial Temperature Observations, received at the Admiralty in the year 1888 (et seq.) from H.M.

Observations were made on a ring in a pine-wood for a period of nine years, and it was calculated that it increased from centre to circumference about 82 in.

Like Horace he largely illustrated his own observations by personal anecdotes and fables.

Experiments and Observations on Electricity (London, 1769) was translated into French by Barbeu Dubourg (Paris, 1773); Vaughan attempted a more complete edition, Political, Miscellaneous and Philosophical Pieces (London, 1 779); an edition in three volumes appeared after Franklin's death (London, 1806); what seemed the authentic Works, as it was under the care of Temple Franklin, was published at London (6 vols., 1817-1819; 3 vols., 1818) and with some additional matter at Philadelphia (6 vols., 1818).

During his tenure of the latter chair he distinguished himself by observations on the lymphatics.

His chapter on the flea, in which he not only describes its structure, but traces out the whole history of its metamorphoses from its first emergence from the egg, is full of interest - not so much for the exactness of his observations, as for its incidental revelation of the extraordinary ignorance then prevalent in regard to the origin and propagation of "this minute and despised creature," which some asserted to be produced from sand, others from dust, others from the dung of pigeons, and others from urine, but which he showed to be "endowed with as great perfection in its kind as any large animal," and proved to breed in the regular way of winged insects.

Ctesibius of Alexandria, Hero and others, founded the science of pneumatics on observations on the physical properties of air.

The constancy of composition shown by repeated analyses of atmospheric air led to the view that it was a chemical compound of nitrogen and oxygen; but there was no experimental confirmation of this idea, and all observations tended to the view that it is simply a mechanical mixture.

The establishment of a system of magnetic observatories in various parts of British territory all over the globe was accomplished mainly on his representations; and a great part of his life was devoted to their direction, and to the reduction and discussion of the observations.

Nearly every one of the modern instruments used for the observations of physical astronomy is a part of the perfected astrolabe.

Meteorological statistics are collected at Auckland, Wellington, Christchurch, and Dunedin and eight other stations; and observations of rainfall, temperature, and wind-directions are received from eighteen stations of the second class.

The results of his observations during his journey through England and Scotland appeared in a tract De l'Angleterre et des Anglais; and his conversations with distinguished men in those countries contributed to greater correctness in the exposition of principles in the third edition of the Traite, which appeared in 1817.

On the side of the philosophy of science his observations are usually commonplace or superficial.

It is convenient to give this calculation before proceeding to describe the experimental determination of the velocity in air, in other gases and in water, since the calculation serves to some extent as a guide in conducting and interpreting the observations.

But when the wind is steady its effect may be eliminated by " reciprocal " observations, that is, by observations of the time of passage of sound in each direction over the measured distance..

There were also two intermediate stations at which observations were made.

Regnault in the years 1862 to 1866 on the velocity of sound in open air, in air in pipes and in various other gases in pipes, he sought to eliminate personal equaticn by dispensing with the human element in the observations, using electric receivers as observers.

America, he made observations on the geology, published by the Geological Society in 1860.

His name is chiefly known for his mineralogical observations and for his work on soluble glass.

As to the details, the following observations 2 may be made for the last phase of the empire which expired in 1918.

He established an astronomical observatory at Paramatta in 1822, and the Brisbane Catalogue, which was printed in 1835 and contained 7385 stars, was the result of observations made there in 1822-1826.

Important magnetic observations were begun at Makerstoun in 1841, and the results gained him in 1848 the Keith prize of the Royal Society of Edinburgh, in whose Transactions they were published.

Early in life he published observations on the Tertiary and Post-Tertiary deposits in the Thames valley, and on fossil plants and various invertebrata, in the Magazine of Natural History, the Annals of Nat.

The building was finished in 1832, and the instruments were ready for work in 1835, from which date the observations were published in 4to volumes (Annales de l'Observatoire Royal de Bruxelles), but Quetelet chiefly devoted himself to meteorology and statistics.

He made a great number of observations of stars with proper motion.

He organised extensive magnetical and meteorological observations, and in 1839 he started regular observations of the periodical phenomena of vegetation, especially the flowering of plants.

Only a few general observations can be made here.

Meyer's observations, they attain a length of from 17 to 18 mm.

Alston's observations were founded on what occurred in certain unisexual plants, such as Mercurialis, Spinach, Hemp, Hop and Bryony.

The interesting observations of Morland, already quoted, seem to have been neglected, and no one attempted to follow in the path which he had pointed out.

In his Statical Essays (1727) he gave an account of numerous experiments and observations which he had made on the nutrition of plants and the movement of sap in them.

As early as 1831 (during the annular eclipse of the sun) she had been her father's assistant in his observations.

In this attempt he was unsuccessful, but the observations he made in the course of his experiments induced him, early in 1856, to try the effect of treating aniline sulphate with bichromate of potash.

He also edited Coeli et siderum in eo errantium observationes Hassiacae (1618), containing the astronomical observations of Landgrave William IV.

The French observations were published in 1792 (Expose des operations faites en France in 1787 pour la jonction des observatoires de Paris et de Greenwich).

The method was proposed by Legendre only as a convenient process for treating observations, without reference to the theory of probability.

The island is not permanently inhabited, but has been frequently visited by explorers, sealers and whalers; and an Austrian station for scientific observations was maintained here for a year in 1882-1883.

In 1862 he received the gold medal of the latter society, and in 1864 a Royal medal from the Royal Society, for his observations on the total eclipse of the sun in 1860, and for his improvements in astronomical photography.

He became intimate with James Bradley in 1755, and in 1761 was deputed by the Royal Society to make observations of the transit of Venus at St Helena.

Subsequent volumes of the same series contained his observations of the transits of Venus (1761 and 1769), on the tides at St Helena (1762), and on various astronomical phenomena at St Helena (1764) and at Barbados (1764).

He further induced the government to print his observations annually, thereby securing the prompt dissemination of a large mass of data inestimable from their continuity and accuracy.

His observations appeared in four large folio volumes (1776-1811).

He calculated an orbit for the comet of 1 759 (Halley's), reduced Lacaille's observations of 515 zodiacal stars, and was, in 1763, elected a member of the Academy of Sciences.

Owing to the famine and the disturbed state of the country, which demanded his attention as a large landowner and lieutenant of King's County (from 1831), the instrument remained unused for nearly three years, but since 1848 it has been in constant use, chiefly for observations of nebulae, for which it was particularly suited on account of its immense optical power, nominally 6000.

Aperture, and a Selection from the Observations of Nebulae made with them," with numerous engravings.

The accounts of the observations given in these papers, however, were fragmentary; but in 1879-80 a complete account of them was published by the present earl ("Observations of Nebulae and Clusters of Stars made with the 6-foot and 3-foot Reflectors at Birr Castle from 1848 to 1878") in the Scient.

An increasing number of workers in this field of plant biology in England, on the Continent and in America has produced a great mass of observations, which have recently been brought together in Dr Paul Knuth's classic work, Handbook of Flower Pollination, an English translation of which has been published (1908) by the Clarendon Press.

The amount of sediment carried down is very large, though no accurate observations have been made.

Direct material for answering the question when and how far astronomical calculations replaced simple observations as the basis of the Jewish calendar is not forthcoming.

Richard, was followed in 1820 by an original Monographia Rosarum, with descriptions of new species, and drawings executed by himself, and in 1821 by Monographia Digitalium, and by "Observations on Pomaceae," contributed to the Linnean Society.

Becoming interested in terrestrial magnetism he made many observations of magnetic intensity and declination in various parts of Sweden, and was charged by the Stockholm Academy of Sciences with the task, not completed till shortly before his death, of working out the magnetic data obtained by the Swedish frigate "Eugenie" on her voyage round the world in 1851-1853.

A few observations of a general character will therefore suffice in this place.

One of the chief observations recorded in it is that the atmosphere is composed of two gases - one which supports combustion and the other which prevents it.

Of his numerous publications, For the use of the drum in the 16th century, see Sir John Smyth, Instructions and Observations for all Chieftaines, Captaines, &c. (London, 1 595), pp. 158-159.

An early observatory, where in 1822 were made the observations for the Parramatta Catalogue, numbering 7385 stars, has long been abandoned.

With the object of reaching fainter stars, Professor Pickering constructed another instrument of larger dimensions, and with this more than a million observations have been made.

Lyell marshalled all the observations he could collect in support of this principle, teaching that the present is the key to the past, and arraying all obtainable evidence against the cataclysmic theories of Cuvier.

Thus the recapitulation law, which had been built up independently from the observations and speculations on vertebrates by Lorenz Ofen (1779-1851), Johann Friedrich Meckel (1781-1833), St Hilaire, Karl Ernst von Baer (1;92-1876) and others, and had been applied (1842-1843) by Karl Vogt (1817-1895) and Agassiz, in their respective fields of observation, to comparison of individual stages with the adults of the same group in preceding geological periods, furnished the key to the determination of the ancestry of the invertebrates generally.

While in Greece he made observations which showed that in ancient architecture the use of polychrome was frequent.

Silurian and Devonian fossils have been reported at one or two localities, but for the present the observations are open to doubt.

Struve's name is best known by his observations of double stars, which he carried on for many years.

His observations on the three comets of 1618 were published in De Cometis, contemporaneously with De Harmonice Mundi (Augsburg, 1619), of which the first lineaments had been traced twenty years previously at Gratz.

His university career lasted three years, and on its termination he became a tutor at Toxteth, devoting to astronomical observations his brief intervals of leisure.

He also reduced the solar parallax to 14" (less than a quarter of Kepler's estimate), corrected the sun's semi-diameter to 15' 45", recommended decimal notation, and was the first to make tidal observations.

After his death (which occurred soon after that of his friend) these were purchased by Dr Worthington, of Cambridge; and from his hands the treatise Venus in sole visa passed into those of Hevelius, and was published by him in 1662 with his own observations on a transit of Mercury.

But in the following observations we deal generally with the more important features of riding as practised astride.

Thus the heaviest measured rainfall east of the Mississippi is on the southern Appalachians; while in the west, where observations are as yet few at high level stations, the occurrence of forests and pastures on the higher slopes of mountains which rise from desert plains clearly testifies to the same rule.

He accepted also the division into five zones; he quotes approvingly the assertion of Hipparchus that it was impossible to make real advances in geography without astronomical observations for determining latitudes and longitudes.

During an attack of fever he made observations on himself with reference to the action of quickened circulation upon thought, which led him to the conclusion that psychical phenomena were to be accounted for as the effects of organic changes in the brain and nervous system.

An inquirer who examines the stars with a shilling telescope is not likely to make observations of value, and even a trained astronomer has to allow for his "personal equation" - a point to which even a finished critic rarely attends.

Sosigenes Could Scarcely Fail To Know That This Year Was Too Long; For It Had Been Shown Long Before, By The Observations Of Hipparchus, That The Excess Of 3654 Days Above A True Solar Year Would Amount To A Day In 300 Years.

In 1755 he submitted to the English government an amended body of MS. tables, which James Bradley compared with the Greenwich observations, and found to be sufficiently accurate to determine the moon's place to 75", and consequently the longitude at sea to about half a degree.

They are employed for taking observations of the density of sea-water.

He also made observations on the flight of rockets, and wrote on the advantages of rifled barrels.

In this theory there can strictly be no "causation"; one thing is observed to succeed another, but observations cannot assert that it is "caused" by that thing; it is post hoc, but not propter hoc. The idea of necessary connexion is a purely mental idea, an a priori conception, in which observation of empirical data takes no part; empiricism in ethics likewise does away with the idea of the absolute authority of the moral law as conceived by the intuitionalists.

The Copernican theory of the solar system - that the earth revolved annually about the sun - had received confirmation by the observations of Galileo and Tycho Brahe, and the mathematical investigations of Kepler and Newton.

In 1680 Jean Picard, in his Voyage d'Uranibourg, stated, as a result of ten years' observations, that Polaris, or the Pole Star, exhibited variations in its position amounting to 40" annually; some astronomers endeavoured to explain this by parallax, but these attempts were futile, for the motion was at variance with that which parallax would occasion.

Hooke, in 1674, published his observations of y Draconis, a star of the second magnitude which passes practically overhead in the latitude of London, and whose observations are therefore singularly free from the complex corrections due to astronomical refraction, and concluded that this star was 23" more northerly in July than in October.

The instrument was set up in November 1725, and observations on y Draconis were made on the 3rd, 5th, 11th, and 12th of December.

On the 17th of December, however, Bradley observed that the star was moving southwards, a motion further shown by observations on the loth.

The observations were continued, and the star was seen to continue its southerly course until March, when it took up a position some 20" more southerly than its December position.

Bradley had already perceived, in the case of the two stars previously scrutinized, that the apparent difference of declination from the maximum positions was nearly proportional to the sun's distance from the equinoctial points; and he realized the necessity for more observations before any generalization could be attempted.