scholarly journals On the results of tide observations, made in June 1834, at the Coast-Guard stations in Great Britain and Ireland

1837 ◽  
Vol 3 ◽  
pp. 329-330
Keyword(s):  
High Water ◽  
Coast Guard ◽  
Maximum Magnitude ◽  
The Moon ◽  
Diurnal Difference ◽  
Exact Determination ◽  
The Subject ◽  
The Times ◽  
Two Sides ◽  
Made In

On a representation made by the author of the advantages which would result from a series of simultaneous observations of the tides, continued for a fortnight, along a great extent of coast, orders were given for carrying this measure into effect at all the stations of the Preventive service on the coasts of England, Scotland, and Ireland, from the 7th to the 22nd of June inclusive. From an examination of the registers of these observations, which were transmitted to the Admiralty, but part of which only have as yet been reduced, the author has been enabled to deduce many important inferences. He finds, in the first place, that the tides in question are not affected by any general irregularity, having its origin in a distant source, but only by such causes as are merely local, and that therefore the tides admit of exact determination, with the aid of local meteorological corrections. The curves expressing the times of high water, with relation to those of the moon’s transit, present a very satisfactory agreement with theory; the ordinates having, for a space corresponding to a fortnight, a minimum and maximum magnitude, though not symmetrical in their curvatures on the two sides of these extreme magnitudes. The amount of flexure is not the same at different places; thus confirming the result already obtained by the comparison of previous observations, and especially those made at Brest; and demonstrating the futility of all attempts to deduce the mass of the moon from the phenomena of the tides, or to correct the tables of the tides by means of the mass of the moon. By the introduction of a local, in addition to the general, semimenstrual inequality, we may succeed in reconciling the discrepancies of the curve which represents this inequality for different places; discrepancies which have hitherto been a source of much perplexity. These differences in the semimenstrual inequality are shown by the author to be consequences of peculiar local circumstances, such as the particular form of the coast, the distance which the tide wave has travelled over, and the meeting of tides proceeding in different directions; and he traces the influence of each of these several causes in producing these differences. A diurnal difference in the height of the tides manifests itself with remarkable constancy along a large portion of the coast under consideration. The tide hour appears to vary rapidly in rounding the main promontories of the coast, and very slowly in passing along the shores of the intervening bays; so that the cotidal lines are brought close together in the former cases, and, in the latter, run along nearly parallel to the shore; circumstances which will also account for comparative differences of level, and of corresponding velocities in the tide stream. The author intends to prosecute the subject when the whole of the returns of these observations shall have undergone reduction.

scholarly journals V. On the results of tide observations made in June 1834 at the coast guard sta­tions in Great Britain and Ireland

1835 ◽  
Vol 125 ◽  
pp. 83-90 ◽  
Keyword(s):  
East Coast ◽  
Coast Guard ◽  
Preventive Service ◽  
The Moon ◽  
First Approximation ◽  
Service Stations ◽  
The Mean ◽  
The Times ◽  
Mean Time ◽  
Made In

In the conclusion of “An Essay towards a first Approximation to a Map of Cotidal Lines," published in the Philosophical Transactions for 1833, I stated my opinion that simultaneous tide observations, made at the stations of the Preventive Service, and continued for a fortnight, would give us a clearer view of the progress of the tide along the coasts of this country than we could acquire from any records then extant. A representation to this effect being made to Captain Bowles, the Chief Commis­sioner of that Service, and to Captain Beaufort, the Hydrographer of the Admiralty, those gentlemen entered with great interest and activity into the proposal for promoting this branch of science by such a series of observations; and they undertook to give orders for carrying the plan into effect, and directions for its execution. Such observations were accordingly made at all the Preventive Service stations on the coasts of England, Ireland, and Scotland, from June 7 to June 22 inclusive, and the registers of the observations were sent to the Admiralty, where they now are. I expected to be able to deduce from these returns the solution of several curious and important questions respecting the tides, and probably to obtain some new laws of their phenomena. For this purpose, however, it was necessary to perform a pre­vious reduction of the registered observations, correcting the times as far as the methods employed would allow, and subtracting from each time of tide the time of the previous transit of the moon, in order to obtain the interval. Though this opera­tion was very simple, the performance of it in so many cases (above 12,000) required more time than I could devote to it. Captain Beaufort kindly allowed it to be exe­cuted by Mr. Dessiou, of the Hydrographer’s Office ; and it was my intention to defer laying the account of the observations before the Society till the whole of them had been reduced, and their results investigated. But Mr. Dessiou, having executed this reduction for the whole of the south coast of England, has been prevented by illness and by more pressing employments, from proceeding to the remaining coasts. In the mean time, having examined the reduced observations, I have been led to some conclusions which appear to me interesting and important ; and which, I think, con­sidering the delay which may attend the reduction of the remaining returns, and the intention which is entertained of repeating the observations in the ensuing June, it may be worth while very briefly to announce. I shall defer the communication of the details by which these results are established till I am able to include in them the east coast of England and the coasts of Ireland and Scotland.

scholarly journals The association of the Royal Sociey with progress in knowledge of oceanic tides

1939 ◽  
Vol 2 (2) ◽  
pp. 140-143
Keyword(s):  
Theoretical Work ◽  
High Water ◽  
Early Years ◽  
The Moon ◽  
Directed Attention ◽  
Oceanic Tides ◽  
The Subject ◽  
The Times ◽  
Theoretical Considerations ◽  
Diurnal Tides

It is now well known that the tides of the ocean constitute a gravitational phenomenon in which the moon plays a large part, and that it was Newton’s Principia , published in 1687, which laid the foundations of all sound theoretical work upon the subject. But before the appearance of the Principia and in the very early years of the Society, Wallis, Flamsteed and Halley, as well as Sir R. Moray, S. Colepresse, H. Philips, S. Sturmy and J. Childrey, published papers on tides in the Philosophical Transactions . Wallis, in 1666, based his theoretical considerations on Galileo’s ideas, and came very near to discovering some of the features of gravitation. A number of his points were taken up by Childrey, in 1670, and compared with the results of the observations of seamen. Halley’s paper of 1684 was also concerned with general principles, and quoted observations on the diurnal tides of Tonkin taken by F. Davenport. Philips studied the tides observed at London, and in the years 1682^84 Flamsteed, the first Astronomer-Royal, gave tide-tables for London Bridge, together with differences between the times of high water at London Bridge and those of high water at other places. Moray, in 1666, discussed methods of observing tides, while in 1668 Colepresse and Sturmy dealt with observations at Plymouth and Bristol respectively. In the Principia Newton gave an analysis of the tide-producing forces on the principles of gravitation, and then proceeded to account for many of the general features of the observed tides. These included the semidiurnal nature of the principal tides, the diurnal inequality, and the phenomena of spring tides and neap tides. In the Philosophical Transactions for 1697 Halley directed attention to the excellence of this part of Newton’s work.

XIV. Researches on the tides. —Twelfth series. On the laws of the rise and fall of the sea's surface during each tide

1840 ◽  
Vol 130 ◽  
pp. 255-272 ◽  
Keyword(s):  
Usual Care ◽  
Tide Gauge ◽  
High Water ◽  
Present Communication ◽  
The Subject ◽  
The Times ◽  
The Moment ◽  
Surface Passing

The subject of the present communication is different in its nature from those of previous memoirs on the tides presented by me, and printed by the Society; since it refers, not to comparison of the times and heights of different tides, but to the rate of the rise and fall of the surface of the water in successive stages of the same tide. This inquiry has often been prosecuted at particular places by naval observers, and is of very material importance to navigation. For even supposing the time and height of high water to be known, it is still often requisite, for nautical purposes, to know the height of the water at a given interval before or after the moment of high water. And this inquiry may be the more useful, inasmuch as the laws of rise and fall of the surface are nearly the same at all places; the differences being, for the most part, of such a kind as can be ascertained and allowed for without much difficulty. Hence these laws, once stated, will be applicable on every coast; and the knowledge of them may supersede those laborious trains of observation which have often been instituted in order to ascertain the laws at particular places. The materials of the present investigation (which is principally founded upon ob­servation) are the following: —Five months’ tide observations made at Plymouth, in which, besides the time and height of high and low water, the time of the surface passing two lines above the level of mean water was carefully observed; these latter observations being made, at my request, by direction of the Lords Commissioners of the Admiralty: —Three months’ observations (taken out of a larger series) made at Liverpool, under the direction of Capt. Denham, R. N., in which the height of the surface was noted every half hour: —and twelve months’ observations made at Bristol by Mr. Bunt, by means of his tide-gauge. The latter observations were reduced by Mr. Bunt himself; the others were discussed under my direction by Mr. Dessiou and Mr. Ross, of the Hydrographer’s Office, with their usual care and skill.

scholarly journals On the lunar theory

1837 ◽  
Vol 3 ◽  
pp. 25-27
Keyword(s):  
Numerical Computation ◽  
Lunar Theory ◽  
The Moon ◽  
Extreme Length ◽  
The Subject ◽  
Made In

The subject treated of in this paper is introduced by a review of the labours of Clairault, Euler, D’Alembert, and Thomas Simpson. The theories of these eminent men, the author remarks, were very deficient in accuracy, and were not at all adequate, without correction from observation, to the construction of tables. They could serve only to point out the arguments of the equations, and not all even of these. The inequalities of the moon’s motion are investigated by approximating processes, which lead to results more or less accurate, according as the approximations are carried to a greater or less extent. The writers above mentioned had contented themselves with short and easy approximations; and though they had accomplished much, had yet left much more to be done. Subsequently to these, Mayer published an elaborate theory of the moon; but his coefficients required much correction, the results of his computations being m some cases found to differ very widely from observation. A much greater degree of accuracy was attained by La Place, who bestowed particular attention on the influence of minute quantities in every part of his theory. In the present paper the author has endeavoured to introduce further improvements in the lunar theory, by carrying the approximations considerably further than they have hitherto been made. In the solutions of the problem given by former mathematicians, the chief obstacle to the attainment of accuracy was the extreme length and labour of the necessary computations. Another object, therefore, which the author has had in view, is to facilitate these computations, and render them less laborious. This he endeavours to effect by the employment of certain artifices, by which the multiplicity of small terms will, with their co-efficients, be reduced within a practicable compass, and their numerical computation rendered less appalling.

scholarly journals The Bakerian lecture. - On the radiation of heat from the moon, the law of its absorption by our atmosphere, and its variation in amount with her phases

1873 ◽  
Vol 21 (139-147) ◽  
pp. 241-242 ◽  
Keyword(s):  
Royal Society ◽  
Zenith Distance ◽  
The Moon ◽  
Single Curve ◽  
The Subject ◽  
The Law ◽  
Made In

In this paper is given an account of a series of observations made in the Observatory of Birr Castle, in further prosecution of a shorter and less carefully conducted investigation, as regards many details, which forms the subject of two former communications to the Royal Society. The observations were first corrected for change of the moon’s distance from the place of observation and change of phase during the continuance of each night’s work, and thus a curve, whose ordinates represented the scale-readings (corrected) and whose abscissas represented the corresponding altitudes, was obtained for each night’s work. By combining all these, a single curve and table for reducing all the observations to the same zenith-distance was obtained, which proved to be nearly, but not quite, the same as that found by Professor Seidel for the light of the stars.

scholarly journals XVII. Researches on the tides.—Sixth series. On the results of an extensive system of tide observations made on the coasts of Europe and America in June 1835

1836 ◽  
Vol 126 ◽  
pp. 289-341 ◽  
Keyword(s):  
The Netherlands ◽  
The United States ◽  
General Purpose ◽  
Coast Guard ◽  
General Interest ◽  
General Direction ◽  
The North ◽  
The Subject ◽  
Foreign Governments ◽  
Made In

1. I have already, in communications to the Society, urged the importance which belongs to simultaneous tide observations made at distant places; and I have also stated some of the steps which have been taken in consequence of representations to this effect. Observations were made and continued for a fortnight in June 1834, at the coast-guard stations in Great Britain and Ireland; and I have given an account of some of the results of these observations in a paper already printed in the Transactions. Being encouraged by the general interest taken in the subject, and by the desire to promote this branch of knowledge manifested by those who had officially the means of doing so, especially by Captain Beaufort, the Hydrographer of the Admiralty, I solicited a repetition of the coast-guard tide observations in June 1835, and also ventured to recommend that a request should be made to other maritime nations, to institute simultaneous tide observations on their coasts. The British observations were undertaken with the same readiness as before by Captain Bowles, the Chief Commissioner of the Coast-Guard Service. The proposal for the foreign observations was entertained and promoted with great zeal by the Board of Admiralty; and the Duke of Wellington, at that time Foreign Secretary of State, being applied to, to forward the scheme, His Grace fully acceded to the application, and made requests to foreign governments to join in the undertaking, in a manner which procured from them the most cordial and effective cooperation. Through the ambassadors of the maritime powers of Europe, and through A. Vail, Esq., the Chargé d’Affaires of the United States, who entered into this design with great interest, arrangements were made, and directions circulated, for simultaneous tide observations from the 8th to the 28th of June. These observations were made, for the most part with great care, under the direction of intelligent officers and men of science. 2. The chain of places of observation extended from the mouth of the Mississippi, round the Keys of Florida, along the coast of North America, as far as Nova Scotia; and from the Straits of Gibraltar, along the shores of Europe, to the North Cape of Norway. The number of places of observation was twenty eight in America, seven in Spain, seven in Portugal, sixteen in France, five in Belgium, eighteen in the Netherlands, twenty-four in Denmark, and twenty-four in Norway; and observations were made by the coast-guard of this country at 318 places in England and Scotland, and at 219 places in Ireland. Among the persons who superintended these observations on an extensive scale, I have profited in an especial manner by the labours of M. Möll, who directed and arranged those made in the Netherlands; M. Tegner, who has performed various reductions on the Danish observations, besides superintending a large portion of them; and M. Beautems-Beaupre, who has for some years been occupied with valuable hydrographical labours on the coasts of France. In several other cases in which the observations have been conducted in a very accurate and scientific manner, I do not find it stated, in the communications which contain the registers, under whose general direction the operations were carried on. The names of the particular observers will be found in the Tables appended to this memoir. I have not used the whole of the observations sent; as some, from the situation of the places, or from other causes, could not be made subservient to my general purpose. For instance, I have for the present omitted some, on account of their manifestly irregular character; others, because, being made at some distance up the course of a river, they gave no information respecting the tides of the ocean. Such data as these last mentioned may still be of use to myself or other investigators on some future occasion.

XII. Researches on the tides.—fifth series. On the solar inequality and on the diurnal inequality of the tides at Liverpool

1836 ◽  
Vol 126 ◽  
pp. 131-147 ◽  
Keyword(s):  
Present State ◽  
High Water ◽  
Present Form ◽  
Equilibrium Theory ◽  
Complete Agreement ◽  
Great Success ◽  
Fourth Series ◽  
The Subject ◽  
The Times

Sect. 1. Present State of the subject . 1. The great success with which recent researches on the Tides have been attended, has encouraged me to attempt some further advances in this subject. The laws of the semimenstrual inequality of the times were shown by Mr. Lubbock, from the London observations, to agree very closely with the equilibrium-theory: and this result has been confirmed by the examination of observations made at many other places. I have shown, from the Liverpool observations, that the semimenstrual inequality of the heights presents a still more complete agreement with the equilibrium-theory; and by the help of Mr. Lubbock’s discussions of the London and of the Liverpool observations, I have shown, in the Second and Fourth Series of these Researches, that the inequalities depending on the changes of lunar parallax and declination may be very well represented by the equilibrium-theory, with certain modifications, which are far from inconsistent with the best mechanical views we can at present form of the laws of the motion of fluids. The most obvious points which now remain requiring still to be made out and explained, are the diurnal inequality, and the solar inequalities of the time and height of high water.

On The Origins Of Knowledge Of The Sea Tides From Antiquity To The Thirteenth Century

2001 ◽  
Vol 20 (2) ◽  
pp. 105-126 ◽  
Author(s):  
David Cartwright
Keyword(s):  
Western Europe ◽  
Practical Knowledge ◽  
The Moon ◽  
Medieval Period ◽  
Greek Poetry ◽  
Tidal Bore ◽  
Personal Bias ◽  
The Subject ◽  
The Times ◽  
Evident Relationship

This is an exhaustive survey of the first written records concerning sea-tides and hypotheses for their cause, covering a period from 500 B.C.E. to 1250 C.E. Seamen of antiquity must have gained practical knowledge of tides by experience, but they left no written record. Despite some early Greek references to the subject, the Hellenic civilisation knew little about tides until the reports of travellers like Pytheas and Posidonius (135-51 B.C.E.), Many of the first informed writings are now lost but their gist is known to us, allowing for personal bias and distortion, through Geography by Strabo (ca. 63 B.C.E.-ca. 25 C.E.). Arab astrologers were impressed by the evident relationship to the Moon; they wrote seminal treatises, later translated and copied widely in western Europe. Nevertheless, some non-lunar hypotheses from Greek poetry, involving ocean currents, undersea caverns, and whirlpools, survived through translations for many centuries. During the Medieval period knowledge in Europe was preserved by Christian monks and extended by their observations. Meanwhile, understanding in China developed to the construction of the first known tide-table for predicting the times and heights of a tidal bore, around 1000 C.E.

scholarly journals The Bakerian Lecture. An account of experiments to determine the amount of the dip of the magnetic needle London, in August 1821; with remarks on the instruments which are usually employed in such determinations

1833 ◽  
Vol 2 ◽  
pp. 155-156
Keyword(s):  
Nursery Ground ◽  
The North ◽  
The Subject ◽  
The Difference ◽  
Regent's Park ◽  
The Times ◽  
Magnetic Meridian ◽  
Magnetic Needle ◽  
Source Of Error ◽  
Made In

After describing the imperfections of the instruments in general use for ascertaining the dip of the magnetic needle, and adverting to the consequent inaccuracy and insufficiency of the observations made with them, Captain Sabine gives an account of the form of dipping-needle which he preferred for his experiments, and which was con­structed for him by Mr. Dollond, upon principles laid down by Pro­fessor Meyer, of Gottingen. He then enters into minute details of the mode of pursuing and verifying his observations, the results of which, gained by three different methods, are as follows: viz. by 10 experiments with Meyer’s needle, 70° 2'.9; by the times of oscil­lation in the magnetic meridian, and in the plane perpendicular to it (mean by three needles), 70° 04'; by the times of vertical and hori­zontal oscillation, 7° 02'.6. So that 70° 03' may be considered as the mean dip of the needle towards the north, in August and Sep­tember 1821, within four hours of noon, being the limit within which all the experiments were made. Alluding to former observations for the purpose of determining the dip in London, the author observes that, independent of any im­perfection in the instruments, they were made in houses in close built parts of the metropolis, and, therefore, all subject to the in­fluence of local attraction; and, moreover, that the correction found by observing the difference of the dip on the outside of the house cannot be regarded as an effectual remedy, inasmuch as the needle may still have been attracted by iron in the adjoining houses, or in the neighbourhood. It is, indeed, only requisite to try needles in different situations in a city, to be convinced how little dependence should be placed in the accuracy of such results: the author thinks that it is rather owing to this cause than to instrumental error, that the dip at the Apartments of the Royal Society is stated in the Phi­losophical Transactions for the present year to be 71° 06'. To avoid this source of error, Captain Sabine conducted the observations which form the subject of this lecture in the nursery-ground in the Regent’s Park, a situation which he regards in all respects eligible, and far removed from the influence of iron.

scholarly journals XI. On the harmonic analysis of tidal observations of high and low water

1891 ◽  
Vol 48 (292-295) ◽  
pp. 278-340
Keyword(s):  
Harmonic Analysis ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Tide Gauge ◽  
The Moon ◽  
The North ◽  
The North Atlantic ◽  
The Times ◽  
The Relationship ◽  
Made In

Extensive use of the tide-gauge has only been made in recent years, and by far the largest number of tidal records consist only of observations of high and low water (H. and L. W.). Such observations have usually been reduced by determining the law governing the relationship between the times and heights of H. and L. W. and the positions of the moon and sun. This method is satisfactory so long as the diurnal inequalities are small, but it becomes both complex and unsatisfactory when the diurnal inequality is large. In such cases the harmonic notation for the tide is advantageous, and as, except in the North, Atlantic Ocean, the diurnal inequality is generally considerable, a proper method of evaluating the harmonic constants from H. and L. W. observations is desirable.

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