The Physical Geography of the Sea, and its Meteorology. Being a reconstruction and enlargement of the eighth edition of 'The Physical Geography of the Sea.' Illustrated with numerous charts and diagrams

Front matter

THE PHYSICAL GEOGRAPHY OF THE SEA, ANT) ITS METEOROLOGY. THE PHYSICAL GEOGRAPHY OP THE SEA, AND ITS METEOROLOGY. BEING A RECONSTRUCTION AND ENLARGEMENT OF THE EIGHTH EDITION OF "THE PHYSICAL GEOGRAPHY OF THE SEA." BY M. F. MATJBY. LL.D., U.S.N, stjtf;[:intent>ent to the national observatory, Washington. JIILILirjSTIffiAMB WITTH HHJMTSIKOHJ3 CHAM'S AH"© BJTAiGKAMS. LONDON: SAMPSON LOW, SON & CO., 47 LUDGATE HILL. 1860. [The. right of Translation it reserved.'] LONDON : PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET In acknowledgment of the services rendered to the cause of a universal system of Meteorological Observations at Sea, and as a tribute of Friendship, this Volume is Dedicated to the Lord Wrottesley by his Obedient Servant, The Author.

Introduction

. The Physical Geography of the Sea is a new department of human knowledge. It has resulted from that beautiful and admirable system of physical research, in which aU the maritime nations have agreed to unite ; and for the furtherance of wliich bureaux have been established, especiahy in Holland, England, France, and the United States. Consequently, research has become very active in this field ; it is diligent, too ; and in proportion to that activity and that diligence has been the advancement of our knowledge concerning the physical GEOGRAPHY OF THE SEA AND ITS METEOROLOGY. It may be doubted whether progress in any department of science has been more rapid than it has been in this. The first treatise upon this subject appeared in America six years ago. Since then such has been the richness of the harvest of facts gathered, that the work has undergone frequent amend ments and improvements; indeed, within that time it has been almost entirely re-written thrice.

This re-writing was necessary because it is a main motive with the author to have the work keep pace with the science itself. The consequence has been, that each re-cast has reaUy made a new work of it. The present edition is not only greatly enlarged above its pre decessors, but it is beheved to be greatly enriched and improved also. It may even be doubted whether in the variety, extent, and value of the information now for the first time presented touching the sea and air, this edition is not so far in advance of former

INTRODUCTION.

. editions as really to make this a new work Where error has been found in previous editions, it has been corrected in this,— where further research has confirmed opinions that in them were ventured as such, the confirmation is here given. The present edition contains a number of chapters entirely new, and not to be found in any of its predecessors. Most, if not aU the chapters contained in them, have also been enlarged, amended, and improved. In short, the author desires here to state to the friends and students of this beautiful and elevating seience, that it is pro gressive — that occupying with regard to it somewhat the relation of a pioneer, his object has been, is, and shaU be, truth. The primary object of the researches connected with " the Wind and Current Charts," out of which has grown this Treatise, was to coUect the experience of every navigator as to the winds and currents of the ocean, to discuss his observations upon them, and then to present the world with the results on charts for the im provement of commerce and navigation.

By putting down on a chart the tracks of many vessels on the same voyage, but at different times, in different years, and during aU seasons, and by projecting along each track the winds and cur rents daily encountered during the voyage, it was plain that navigators hereafter, by consulting such a record, would have for their guide the results of the combined experience of aU whose tracks were thus pointed out. Perhaps it might be the first voyage of a young navigator to the given port, when his own personal experience of the winds to be expected, the currents to be encountered by the way, would itself be blank. If so, there would be the wind and current chart for refer ence. It would spread out before him the tracks of a thousand vessels that had preceded him on the same voyage, wherever it might be,, and that, too, at the same season of the year.

Such a chart, it was held, would show him not only the tracks of the vessels, but the experience also of each master as to the winds and currents by the way, the temperature of the ocean, and the variation of the needle.

INTRODUCTION.

. IX AU this could be taken in at a glance, and thus the young mariner, instead of groping his way along until the hghts of experience should come to him by the slow teachings of the dearest of all schools, would here find, at once, that he had aheady the experi ence of a thousand navigators to guide him on his voyage. He might, therefore, set out upon his first voyage with as much confi dence in his knowledge as to the winds and currents he might. expect to encounter, as though he himself had aheady been that way a thousand times before. Such a chart could not fad to commend itself to intelligent ship masters, and such a chart was constructed for them. They took it to sea, they tried it, and to their surprise and delight they found that, with the knowledge it afforded, the remote corners of the earth were brought closer together, in some instances, by many days' sail.

The passage hence to the equator alone was shortened ten days. Before the commencement of this undertaking, the average passage to Cahfomia was 183 days ; but with these charts for theh* guide, navigators have reduced that average, and brought it down to 135 days. Between England and Australia, the average time going, with out these charts, is ascertained to be 124 days, and coming, about the same • making the round voyage one of about 250 days on the average. These charts, and the system of research to which they have given rise, bid fan to bring that colony and the mother country nearer by many days, reducing in no smaU measure the average duration of the round voyage.* At the meeting of the British Association of 1853, it was stated by a distinguished member — and the statement was again repeated at its meeting in 1854— that in Bombay, whence he came, it was estimated that this system of research, if extended to the Indian Ocean, and embodied in a set of charts for that sea, such as I have * The outward passage, it has since been ascertained, has been reduced to 97 days on the average, and the homeward passage has been made in 63 under canvas a X

INTRODUCTION.

. been describing, would produce an annual saving to British com merce, in those waters alone, of one or two millions of doUars ;* and in aU seas, of ten millions, t A system of philosophical research which is so rich with fruits and abundant with promise could not fail to attract the attention and commend itself to the consideration of the seafaring community of the whole civilized world. It was founded on observation ; it was the result of the experience of many observant men, now brought together for the first time, and patiently discussed. The results tended to increase human knowledge with regard to the laws and phenomena of both sea and air • and therefore the system of research could not be wanting in attractions to right-minded men. The results of the first chart, however, though meagre and un satisfactory, were brought to the notice of navigators • their atten tion was caUed to the blank spaces, and the importance of more and better observations than were generaUy contained in the old sea-logs was urged upon them.

They were told that if each one would agree to co-operate in a general plan of observations at sea, and would send regularly, at * See Inaugural Address of the Earl of Harrowby, President of the British Association at its 24th meeting. Liverpool, 1854. t • . . " Now let us make a calculation of the annual saving to the commerce of the United States effected by those charts and sailing .directions. to Mr. Maury, the average freight from the United States to Rio Janeiro is 177 ets. per ton per day ; to Australia, 20 cts. ; to California, also, about 20 cts. The mean of this is a little over 19 cts. per ton per day ; but to be within the mark, we will take it, at 15, and include all the ports of South America, China, and the East Indies. " The sailing directions have shortened the passages to California 30 days, to Australia 20, to Eio Janeiro 10.

The mean of this is 20, but we will take it at 15, and also include the above-named ports of South America, China, and the East Indies. " We estimate tho tonnage of the United States engaged in trade with these places at 1,000,000 tons per annum. " With these data we see that there has been effected a saving for each one of these tons of 15 cents per day for a period of 15 days, which mil give an gate of $2,250,000 saved per annum. This is on the outward voyage alone, and the tonnage trading with all other parts of the world is also left out of the calcu lation. Take these into consideration, and also the fact that there is a. vast amount of foreign tonnage trading between these places and the United States, aud it will lie seen that the annual Bum saved will swell to an enormous amount." Extract from fluid's Merchant'* Magazine, May, 1854.

INTRODUCTION.

. XI the end of every cruise, an abstract log of his voyage to the National Observatory at Washington, he should, for so doing, be furnished, free of cost, with a copy of the charts and sailing directions that might be founded upon those observations. The quick, practical mind of the enterprising ship-master seized the proposition at once. To him the fieldwas inviting, for he saw in it the promise of a rich harvest and of many useful results. So, in a httle while, there were more than a thousand navigators engaged day and night, and in aU parts of the ocean, in making and recording observations according to a uniform plan, and in fur thering this attempt to increase our knowledge as to the winds and currents of the sea, and other phenomena that relate to the safe navigation of its waters, and to its physical geography.

To enlist the service of such a large corps of observers, and to have the attention of so many clever and observant men directed to the same subject, was a great point gained : it was a giant stride in the advancement of knowledge, and a great step towards its spread upon the waters. Important results soon foUowed, and valuable discoveries were made. These attracted the attention of the commercial world, and did not escape the notice of philosophers generaUy. The field was immense, the harvest was plenteous, and there was both need and room for more labourers. Whatever the reapers should gather, or the merest gleaner coUect, was to inure to the benefit of commerce and navigation— the increase of human know ledge — the good of aU. Therefore, aU who use the sela were equaUy interested in the undertaking.

The government of the United States, so considering the matter, proposed a uniform system of observations at sea, and invited aU the maritime states of Christendom to a conference upon the subject. This conference, consisting of representatives from France, Eng land, and Bussia, from Sweden and Norway, HoUand, Denmark, Belgium, Portugal, and the United States, met in Brussels, August

INTRODUCTION.

. 23, 1853, and recommended a plan of observations which shoidd be foUowed on board the vessels of aU friendly nations, and especiaUy of those there present in the persons of their representatives. Prussia, Spain, Sardinia, Oldenberg and Hanover, the Holy See, the free city of Hamburg, the republics of Bremen and Chili, and the empires of Austria and Brazil, have since offered therr co-operation also in the same plan. Thus the sea has been brought regularly within the domains of philosophical research, and crowded with observers. In peace and in war these observations are to be carried on, and, hi case any of the vessels on board of which they are conducted may be captured, the abstract log — as the journal which contains these observations is caUed — is to be held sacred. The Ulustrious Humboldt, several years before his death, expressed the opinion that the results already obtained from this system of research had given rise to a new department of science, which he caUed the Physical Geography of the Sea.

Barely before has there been such a subhme spectacle presented to the scientific world : aU nations agreeing to unite and co-operate in carrying out according to the same plan, one system of philo sophical research with regard to the sea. Though they may be enemies in aU else, here they are to be friends. Every ship that navigates the high seas with these charts and blank abstract logs on board may henceforth be regarded as a floating observatory, a temple of science. The instruments used by every co-operating vessel are to be compared with standards that are common to aU ; so that an observation that is made anywhere and in any sliip maybe referred to and compared with all similar observations by aU other ships in all parts of the world. But these meteorological observations which this extensive and admirable system includes will relate only to the sea.

This is not enough. The plan should include the land also, and be universal. Other great interests of society are to be benefited by such extension no less than commerce and navigation have been. A series of systematic observations, directed over large districts of country, nay,

INTRODUCTION.

. XIII over continents, to the improvement of agricultural and sanitary meteorology, would, I have no doubt, tend to the development of many interesting, important, and valuable results. With proper encouragement, this plan of research is capable of great expansion. With the aid of the magnetic telegraph, and by establishing a properly devised system of dady weather reports by telegram, sentinelsupon the weather may be so posted that we may have warning in advance of every storm that traverses the country. HoHand, France, and England, have recently established such a plan of dady weather reports from certain stations. And Admiral Fitz Boy, at the head of the Meteorological Department of the Board of Trade in London, informs me that aheady, though the plan went into operation only in the month of September, 1860, yet it is most rich with the promise of a fine harvest of practical results.

The agricultural societies of many states of America have ad dressed memorials to the American Congress, asking for such extension over that continent. This plan contemplates the co-operation of aU the states of Christendom, at least so far as the form, method, subjects of observations, time of making them, and the interchange of results are concerned. Great good is to come of it — shipwrecks and disasters are to be prevented by it — the pubhc weal is to be promoted by it, the convenience of society is to be enhanced by it, the bounds of human knowledge are to be enlarged by it, and it is hoped that the friends of meteorology, and all who may find interest or pleasure in a perusal of these passages, will lend theh assistance to the carrying out of this plan, by advocating it among theh friends.

These researches for the land look not only to the advancement of the great interests of sanitary and agricultural meteorology, but they involve also a study of the laws which regulate the atmosphere, and call for a careful investigation of aU its phenomena. Another beautiful feature in this system is, that it costs nothing additional. The instruments that these observations at sea caU for are such as are aheady in use on board of every well-conditioned

INTRODUCTION.

. ship, and the observations that are required are precisely those which are necessary for her safe and proper navigation. As great as is the value attached to what has been accomplished by these researches in the way of shortening passages and lessening the dangers of the sea, a good of higher value is, in the opinion of many seamen, yet to come out of the moral, the educational influence which they are calculated to exert upon the seafaring community of the world. A very, clever English ship-master, speaking recently of the advantages of educational influences among those who intend to foUow the sea, remarks : " To the cultivated lad there is a new world spread out when he enters on his first voyage. As his education has fitted, so wdl he perceive, year by year, that his profession makes him acquainted with things new and instructive.

His intelligence will enable him to appreciate the contrasts of each country in its general aspect, manners, and productions, and in modes of navigation adapted to the character of coast, climate, and rivers. He will dweU with interest on the phases of the ocean, the storm, the calm, and the breeze, and wdl look for traces of the laws which regulate them. AU this will induce a serious earnestness in his work, and teach him to view lightly those irksome and often offensive duties incident to the beginner."* And that these researches do have such ' an effect many noble hearted mariners have testified. Captain Phinney, of the American ship " Gertrude," writing from Callao, January, 1855, thus ex presses himself: " Having to proceed from this to the Chincha Islands and remain three months, I avail myself of the present opportunity to forward to you abstracts of my two passages over your southern routes, although not required to do so until my own return to the United States next summer ; knowing that you a*-e less amply supphed * " The Log of a Merchant Officer ; viewed with reference to the Educa tion of young Officers and the Youth of the Merchant Service.

By Eohert Methren, Commander in the Peninsular and Oriental Company, and author of the ' Narrative of the Blenheim Hurricane of 1851.'" London: Join. . 59 High Holborn; Smith, Elder* Co., Oorahill ; Ackerman &■ Co., Strand. 1854. TNTRODUOTION. XV with abstracts of voyages over these regions than of many other parts of the ocean, and, such as it is, I am happy to contribute my mite towards furnishing you with material to work out still farther towards perfection your great and glorious task, not only of pointing out the most speedy routes for ships to fellow over the ocean, but also of teaching us sailors to look about us, and see by what wonderful manifestations of the wisdom and goodness of the great God we are continually surrounded. " For myself, I am free to confess that for many years I com manded a ship, and, although never insensible to the beauties of nature upon the sea or land, I yet feel that, until I took up your work, I had teen traversing the ocean blindfolded.

I did not think ; I did not know the amazing and beautiful combination of all the works of Him whom you so beautifully term 'the Great 'First Thought.' "I feel that, aside from any pecuniary profit to myself from your labours, you have done me good as a man. You have taught me to look above, around, and beneath me, and recognize God's hand in every element by which I am surrounded. I am grateful for this personal benefit. Your remarks on this subject, so fre quently made in your work, cause in me feelings of the greatest admiration, although my capacity to comprehend your beautiful theory is very limited. " The man of such sentiments as you express wdl not be dis pleased with, or, at least, wdl know how to execute, so much of what (in a letter of this kind) might be termed irrelevant matter.

I have therefore spoken as I feel, and with sentiments of the greatest respect." Sentiments hke these cannot fad to meet with a hearty re sponse from aU good men, whether ashore or afloat. Admiral Fitz Boy, admitting the value of the practical results aheady derived by commerce and navigation from these researches, is of opinion that their influence in improving and elevating the mind of the British seaman also, can scarcely be of less importance. Never before has such a corps of observers been enlisted in the cause of any department of physical science as is that which is

INTRODUCTION.

. now about to be engaged in advancing our knowledge of the Physical Geography of the Sea, and never before have men felt such an interest with regard to this knowledge. Under the term "Physical Geography and its Meteorology," will be included, a phdosophical account of the winds and currents of the sea ; of the chculation of the atmosphere and ocean ; of the temperature and depth of the sea ; of the wonders that he hidden in its depths ; and of the phenomena that display themselves at its surface. In short, I shaU treat of the economy of the sea and its adaptations — of its salts, its waters, its climates, and its inhabitants, and of whatever there may be of general interest in its commercial uses or industrial pursuits ; — for all such things pertain to this de partment of science. The object of this work, moreover, is to show the present state, and, from time to time, the progress of this new and beautiful system of research, as well as of the advancement made in this interesting department of science ; and the aim of the author is to present the gleanings from this new field in a manner that may be interesting and instructive to aU, whether old or young, ashore or afloat, who desire a closer look into "the wonders of the great deep," or a better knowledge as to its winds, its adaptations, or its Physical Geography.* * There is an old and very rare book which treats upon some of the subjects to which this little work relates.

It is bjy Count L. F. Marsigli, an Italian, and is called Natural Description of the Seas. The copy to which I refer was trans lated into Dutch by Boerhaave in 1786. The learned count made his observations along the coast of Provence aud Lau guedoo. The description only relates to that part of the Mediterranean. The book is divided into four chapters : the first on the bottom and shape of the sea ; the second, of sea water ; the third, on the movements of sea water ; and the fourth, of sea plants. He divides sea water into surface and deep-sea water ; because, when he makes salt from surface water (not more than half a foot below the upper strata), this salt will give a red colour to blue paper ; whereas the salt from deep-sea water will not alter the colours at all. T ho blue paper can only change its colour by on of an acid.

The reason why tins acid (iodine ?) is found in surf. deep-sea water is, it is derived from the air ; but ). I in sea water, by the action of the sun's ray. : the waves, is deprived of its coarse parts, and, by evaporation, embodied in the air to be conveyed to beasts or plants for their existence, oJ deposited upi

INTRODUCTION.

. XVII The results that are embodied in Plate I. alone of this edition would, had the data for it been collected by a force speciaUy employed for the purpose, have demanded constant occupation from a fleet of ten sail for more than one hundred years. The co-ore linating of these observations after they were made, and the bringing of them to the present condensed form, has involved a vast amount of additional labour. Officers here have been engaged upon the'work for many years. This patient industry has been rewarded with the discovery of laws and the development of truths of great value in navigation and very precious to science. It would be presumptuous to claim freedom from ; error for a work like this : true progress consists in the discovery of error as weU as of truth. But I may be pardoned for saying that the present edition of tins work wdl be found to contain more of truth and less of error than any of its predecessors, simply because it is founded on wider research, and based on the resvdts of more abun dant observations than they.

Indeed, it could not, or, rather, it should not be otherwise ; for, as long as we are making progress in any field of physical research, so long must the results continue to increase in value ; and just so long must what at first was con jecture grow and gain as truth, or fade and faU as error. The fact seems now to be clearly established that the atmosphere is very unequally divided on opposite sides of the equator, and that there is a mild climate in the unknown regions of the antarctic circle. Over the extra-tropical regions of our planet, the atmosphere on the polar side of 40° N. and 40° S. is so unequaUy divided as earth's crust, as it occurs on the plains of Hungary, where the earth absoros so mucii of t.'iis saltpetre vapour. Donati, also, was a valuable labourer in this field. His inquiries enabled Mr. Trembley' to conclude that there arc, "at the bottom of the water, mountains, plains, valleys, and caverns, just as upon the land."

But by far the most interesting and va ial iok touching the physical geography of the Mediterranean is Admiral Smyth's ! ititled -The Me- I.ITL.R11ANEAN J A MEMOIR. PHYSICAL, HISTORICAL, AND NAUTICAL. By lilir admiral WjXMAM Hexry Smyth, K.S.F., D.C.L.," &c. 'London : John W. Parker aud Son. 1S54. 1 I'hiluS'.pliical Transactions.

INTRODUCTION.

. to produce an average pressure, according to the paraUel, of from 10 to 50 lbs. less upon the square foot of sea surface in southern than upon the square foot of sea surface in northern latitudes. These, and many other developments not less interesting, seemed to call for a recast of the work. Indeed several new chapters have been added to this edition, and many new subjects have been treated of in it. New views also have been presented, and the errors of former views corrected wherever in them farther research has pointed out error. These researches have grown so wide that they comprehend not only the physics of the sea, but they relate extensively to its meteorology also ; hence the present title, The Physical Geogra phy of the Sea, and its Meteorology. ] Albenw.rU Street, London. 20th November, J8G0. CONTENTS

Chapter I

the sea and the atmosphere.

The two Oceans of Air and Water, § 1.— Their Meeting, 2.— Their Depth, 3.— The Weight of the Atmosphere, 4. — Three fourths below the Mountain-tops, 5. — Its Height, 6. — Data conjectural, 7. — Analysis of Air, 8. — Information respecting the Depth of the Ocean, 9.— Its probable Depth, 10.— Relation between the Depth and the Waves of the Sea, 11.— Airy's Tables, 12.— The Earthquake of Simoda, 13. — The Propagation of its Waves, 14. — Their Breadth and Velocity, 15. — Average Depth of the North Pacific, 16.— Specific Gravity of Sea-water, 17.— Ditto of Air, 18.— Unequal Distribution of Light and Heat, of Air, Water, and Land, 19. — The Sun longer in northern Declination, 20. — England about the Pole of the Hemisphere with most Land, 21. — Effects in the Terrestrial Economy of Inequality in the Distribution of Land and Water, 22. — Quantity of fresh Water in American Lakes, 23. — The southern Seas likened to the Boiler, northern Lands to the Condenser of a Steam-engine, 24. — Offices of the Atmosphere multitudinous, 25.— Dr. Buist, 26. — The Sea and the Atmosphere contrasted, 27. — Influence of the Sun, 28. — Of diurnal Rotation, 29.— Currents, 30. — Icebergs, 31. — Mountain Ranges, 32.— Water, 33.— Latent Heat, 34.— Effects of, upon the Earth, 35.— The Tides, 36.— Hurricanes, 37.— Powers of the Air, 38.— Its Functions, 39.— The Operations of Water, 40. — Its marvellous Power9, 41.— It caters on the Land for the Insects of the Sea, 42. — Leeching, 43.— Solid Ingredients, 44.— Quantity of Silver in the Sea, 45. — Its Inhabitants, their Offices, 46. — Monuments of their Industry, 47. — Analysis of Sea-water, 48. — Proportion of Water to the Mass of the Earth, 49.— The three great Oceans, 50.— The Atlantic, 51.— Its Tides, 52.— Its Depths, 53. — Contrasted with the Pacific, 54. — The Telegraphic Plateau, 55. — New Routes for an Atlantic Telegraph, 56. — The Greenland Route, 57. — The French Route, 58. — Their Length of Circuit, 59. — Faulty Cables, 60. —Their Iron Wrappings, 61. — Imperfect Insulation, 62. — The Red Sea and Mediterranean Cables, 63.— A Galvanic Battery in the Sea, 64.— Two Metals should not be used about a Submarine Cable, 65. — Rogers's Cable "Jacket," 66. — Deep-sea Temperatures a Desideratum, 67. — Specimens from the Depth of 19,800 feet, 68 . .

Page 1

Chapter II

the gulf stream.

Its Colour, § 70.— How caused, 71.— Speculations concerning the Gulf Stream, 72.— Agencies concerned, 73.— Early Writers, 74. — Objection to the fresh-water Theory, 75. — Livingston's Hypothesis, 76. — Franklin's Theory, 77. — Objections to it, 78. — Herschel's Explanation, 79. —Objections to it, 80. — The Supremacy of the Winds disputed, 81.— The Bonifaccio Current, 82. — The Bed of the Gulf Stream an ascending Plane, 83. — The Niagara, 84.— A Current Counter to the Gulf Stream, 85.— Bottle Chart, 86.— Their Drift, 87.— The Sargasso Sea, 83.— A Bifurcation, 89. — Winds exercise but little Influence upon constant Currents, 90. — Effects of diurnal Rotation upon the Gulf Stream, 91. — The Gulf Stream cannot be accounted for by a higher Level, 92.— Nor by the trade-wind Theory, 93. — Illustration, 94. — The Gulf Stream the Effect of some constantly operating Power, 95.— The Pro- C XX CONTENTS. duction of Currents without Wind, 96.— Warm Currents flow towards the Pole, cold towards the Equator, 97.— The Edges of tEeGulf Stream a striking Feature, 98.— Illustrations, 99.— How the Water of the Gulf Stream differs from the littoral Waters, 100.— Action on Copper, 101.— Saltness of the Gulf Stream, 102.— Agents concerned, 103.— Evaporation and Precipitation, 104.— Current into the Caribbean Sea, 105.— Amount of Salt left by Evaporation, 106.— Currents created by Storms, 107.— The dynamical Force that calls forth the Gulf Stream to be Sound in the Difference as to Specific Gravity of intertropical and polar Waters, 108.— Winter Temperature of the Gulf Stream, 109.— The Top of the Gulf Stream roof-shaped, 110.— Drift Matter sloughed off to the right, 111.— Why so sloughed off, 112.— Illustration, 113.— Drift-wood^on the Mississippi, 114.— Effect of diurnal Rotation upon, 115.— Formation of the Grand Banks, 116.— Deep Water near, 117— The Gulf Stream describes in its Course the Path of a Trajectory, 118.— Its Path from Bernini to Ireland, 119.— The Tendency of all Currents, both in the Sea and Air, to move in Great Circles a physical Law, 120.— This Law recognized by the Gulf Stream, 121. — The Shoals of Nantucket do not control its Course, 122.— Herschel's Theory not consistent with known Facts, 123.— The Channel of the Gulf Stream shifts with the Season, 124.— The Phenomenon thermal in its Character, 125. — Limits of the Gulf Stream in March and September, 126. — Reluctance of Layers or Patches to mingle, 127. — Streaks of warm and cool, 128. — Waters of the Ocean kept in Motion by thermo-dynamical Means, 129. — Fig.