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were frequently drifted many miles out of their current upon this part of the coast.* If so, the course without knowing it, and in bad or cloudy course of the Gulf Stream as it disembogues in the weather when many days would intervene from Atlantic, must be a little to the West, instead of a one observation to another, the set of the current, little to the East of North as our charts represent though really felt for but a few hours during the it. My own information, derived from the obserinterval, could only be proportioned out equally vations of an intelligent brother officer, goes to conamong the whole number of days. Therefore Na- firm this opinion; should it be proved correct, it vigators could have only very vague ideas, either will explain the anomaly often remarked opon by as to the strength, or the actual limits of the Gulf Navigators with regard to a stronger current in Stream until they were marked out to the Nan- the Gulf Stream off Cape Hatteras, than further tucket fishermen by the whales, or made known by South, for then, this circumstance may be accounCapt. Folger to Dr. Franklin. The discovery, ted for by the Chart course leading them on the therefore, of its high temperature assured the navi- outer edge of the Gulf Stream until it reaches the gator of the presence of a current of surprising Carolina Capes, where they again get into the velocity, and which, now turned to certain account, strength of it. would hasten, as it had retarded his voyage in a The place of embouchure for the Gulf Stream, is wonderful degree.

about the latitudinal limits of the Trade winds, Such, at the present day, is the degree of per- where calms and variables prevail; and where aid fection to which nautical tables and instruments from currents is most desirable. Our West India have been brought, that the Navigator may now Cruisers are continually passing up and down this detect, and with great certainty, every current that part of the stream; a few turns to and fro across thwarts his way. He makes great use of them. it, by them, would show how the thread of the curCol. Sabine, in his passage a few years ago, from rent does lie, of which we are now ignorant. It Sierra Leone to New York, was drifted 1,600 miles might materially shorten the passage of vessels of his way by the force of currents alone; and, bound North from the Gulf. since the application of the thermometer to the The Gulf Stream, as it issues from the straits Gulf Stream, the average passage from Eng- of Florida, is of a dark indigo blue; the line of land has been reduced from upwards of eight junction between it and the roily green water of weeks, to a little more than four. This may, in the Atlantic, is plainly seen for hundreds of miles. some degree, be owing to the improvement in ship Though this line is finally lost to the eye as the building, but it is less owing, I apprehend, to any stream goes North, it is preserved to the thermomincreased speed of vessels, than to a better know- eter for several thousand miles, yet to this day the ledge of winds and currents ; for the “ Constitu- limits of the Gulf Stream, even in the most fretion” and the “United States” are, at this day, the quented parts of the ocean, though so plainly fastest ships in the Navy; and they are models of marked, are but vaguely described on our charts. the last century.

Thousands of vessels cross it every year; many There is a current constantly setting into the of them make their observations upon it, and many Mediterranean to supply the waste, it is said, of more, if invited would do the same. But no one evaporation. Now, on account of climate, the has invited coöperation; consequently there is no evaporation from the Gulf of Mexico in summer, system, and each one that observes, observes only must be much greater than from the Mediterra- for himself; and when he quits the sea, his obsernean ; moreover, the rivers which empty into the vations go with him and are to the world as though Gulf are all at low water in summer; yet the Gulf they had not been. Stream is said to run with much greater velocity Captain Manderson of the Royal Navy published, in summer than in winter. If so, it is reasonable many years ago, “ An examination into the true to suppose that the waters of the Gulf are higher cause of the Florida stream,” which he ascribed at one season than another. But we have Light to the Mississippi and the floods of the other rivers houses at the Tortugas, the Balize, Mobile and emptying into the Gulf. But judging from what Pensacola, and keepers at them who would be glad we see going on daily in the Mediterranean, the of the employment. A tide staff planted at each, water from the rivers, especially in summer when and daily registered for a year or two, would show the Gulf Stream runs at the greatest velocity, are whether there be a winter and a summer level to not sufficient to supply the waste of evaporation. the Gulf, and thus settle this interesting ques- Taking the hypothesis of the English officer for tion.

granted, it was asserted by another writer, tbat The manner in which the Florida Straits open the velocity of the Gulf stream might be determinout into the Atlantic--inclining to the Westwarded by the freshets in the Mississippi. Capt. Liof North, the contour of the adjacent coast, the deep indent in the shore line here, between St. * April 3. This opinion is still further confirmed by avAugustine and Savannah, all seem to indicate a thentic statements, which I have heard, that the islands oa close pressure of the Gulf Stream and its counter the coast of Georgia bear marks of abrasion from the sea, vingston put these theories to rest by showing that actually forced up an inclined plane, whose submathe volume of waters discharged through the Gulf rine ascent is not less than 10 inches to the mile? Stream, exceeds what is emptied from the Missis- The Niagara is an “immense river descending sippi by more than three thousand times. into a plain.” But instead of preserving its cha

Upon the ruins of this hypothesis which Capt. racter in Lake Ontario as a distinct and well definLivingston had so completely overturned, he ad-ed stream for several hundred miles, it spreads itFanced the opinion that the velocity of the Gulf self out, and its waters are immediately lost in Stream " depends on the motion of the sun in the those of the Lake. Why should not the Gulf Ecliptic, and the influence he has upon the waters Stream do the same? It gradually enlarges itself of the Atlantic.” To this day our books on navi- it is true ; but instead of mingling with the ocean gation quote this opinion without comment. by broad spreading as the “immense rivers" de

The most generally received opinion, however, scending into the Northern lakes do, its waters, is the one repeated by Dr. Franklin, that the Gulf like a stream of oil in the ocean, preserve their Stream is the escaping of the waters that have distinctive character for more than 3,000 miles. been forced into the Carribbean sea by the Trade Moreover, while the Gulf Stream is running to winds; and that it is the pressure of those winds the North from its supposed elevated level at upon the water, which forces up into that sea a the South, there is a cold current coming down head, as it were, for this streain.

from the North ; meeting the warm waters of the We know of instances in which waters have been Gulf midway the Ocean, it divides itself and runs accumulated on one side of a lake, or in one end by the side of them right back into those very reof a canal, at the expense of the other. But they servoirs at the South, to which theory gives an eleare rare, sudden and partial, and for the most part vation sufficient to send out entirely across the Atconfined to sheets of shoal water where the rip- lantic a jet of warm water said to be more than ples are proportionably great. As far as they go, three thousand times greater in volume than the the pressure of the Trade winds may assist to give Mississippi river. This current from Baffin's Bay the Gulf Stream its initial velocity; but is it of has not only no trade winds to give it a head; but itself adequate to such an effect? To my mind, the prevailing winds are unfavorable to it, and for a the laws of Hydrostatics as at present expounded, great part of the way it is below the surface, and appear by no means to warrant the conclusion that far beyond the propelling reach of any wind. And it is, unless the aid of other agents also be brought there is every reason to believe that this polar curto bear.

rent is quite equal in volume to the Gulf Stream. Supposing the pressure of the waters that are Are they not the effects of like causes ? If so, forced into the Carribbean sea by the Trade winds what have the trade winds to do with the one more to be the sole cause of the Gulf Stream, that sea than the other?. and the Mexican Gulf should have a much higher It is a custom often practised by sea-faring peolevel than the Atlantic. Accordingly, the advo- ple to throw a bottle overboard, with a paper stacates of this theory require for its support “ a great ting the time and place at which it is done. In the degree of elevation.” Major Rennell likens the absence of other information as to currents, that stream to “an immense river descending from a afforded by these mute little Navigators is of great higher level into a plain.” Now we know very value. They leave no tracks behind them, it is true ? nearly the average breadth and velocity of the and their routes can not be ascertained. But knowGulf Stream in the Florida pass. We also know, ing where they were cast, and seeing where they with a like degree of approximation, the velocity are found, some idea may be formed as to their and breadth of the same waters off Cape Hatteras. course. Straight lines may at least be drawn, showTheir breadth here is about 75 miles against 32 in ing the shortest distance from the beginning to the the “ Narrows" of the Straits, and their mean ve- end of their voyage, with the time elapsed. I hold locity is 3 knots off Hatteras, against 4 in the in my hand a chart representing in this way the "Narrows." This being the case, it is easy to tracks of more than one hundred bottles. From show that the depth of the Gulf Stream off Hat- it, it appears that the waters from every quarter of teras is not so great as it is in the “ Narrows” of the Atlantic, tend toward the Gulf of Mexico and Bemini by nearly 50 per cent, and that consequent- its Stream. Bottles cast into the sea midway bely, instead of descending, its bed represents the tween the old and the new worlds, near the coasts surface of an inclined plane from the North, up of Europe, Africa and America, at the extreme which the lower depths of the stream must ascend. North or furthest South, have been found either in If we assume its depth off Bemini to be 200 fa- the West Indies, or within the well known range thorns, which are thought to be within limits, the of the Gulf Stream. above rates of breadth and velocity will give 114 Of two cast out together in South latitude on fathoms for its depth off Hatteras. The waters the coast of Africa, one was found on the island therefore, which in the straits are below the level of " Trinidad,” the other on Guernsey, in the Engof the Hatteras depth, so far from descending, are lish channel.

In the absence of positive information on the More water can not run from the equator, or the subject, the circumstantial evidence that the latter pole, than to it. If we make the trade winds cause performed the tour of the Gulf, is all but conclusive. the former, some other wind must produce the lat

Another bottle thrown over off Cape Horn by ter; but these, for the most part, and for great an American master in 1837, has been recently distances, are submarine and therefore beyond the picked up on the coast of Ireland. An inspection influence of winds. Hence, it should appear that of the chart and of the drift of the other bottles winds have little to do with the general system of seems to force the conclusion, that this bottle too aqueous circulation in the Ocean. went even from that remote region to the so called The other“ fork” runs between us and the Gulf higher level of the Gulf Stream reservoir. Stream to the South as already described. As far

Midway the Atlantic, in the triangular space be- as it has been traced, it warrants the belief that it tween the Azores, Canaries and the Cape de Verd too runs up to seek the so called higher level of Islands, is the Sargasso Sea. Covering an area the Mexican Gulf. equal in extent to the Mississippi valley, it is so The power necessary to overcome the resistance thickly matted over with Gulf weed (fucus natans) opposed to such a body of water as that of the that the speed of vessels passing through it, is Gulf Stream, running several thousand miles withoften much retarded. When the companions of out any renewal of impulse from the forces of Columbus saw it, they thought it marked the limits gravitation or any other known cause, is truly surof Navigation and became alarmed. To the eye, prizing. It so happens, that we have an argument at a little distance, it seems substantial enough to for determining, with considerable accuracy, this walk upon. Patches of the weed are always to resistance which the waters of this stream meet be seen floating along the Gulf Stream. Now if with in their motion towards the East. Owing bits of cork or chaff, or any floating substance be to the diurnal rotation, they are carried around put into a basin, and a circular motion he given to with the earth on its axis towards the East with the water, all the light substances will be found an hourly velocity 127* miles greater when they crowding together near the centre of the pool, enter the Atlantic than when they arrive off the where there is the least motion. Just such a basin banks of New Foundland. In consequence of the is the Atlantic Ocean to the Gulf Stream, and the difference of latitude between the parallels of these Sargasso Sea is the centre of the whirl. Columbus two places, their rate of motion around the axis of first found this weedy sea in his voyage of disco- the earth is reduced from 9257 to 758 miles the very, there it has remained to this day, and certain hour. observations as to its limits extending back for Therefore this immense volume of water, in pasfifty years, assure us that its position has not been sing from the Bahamas to the Grand Banks, meets altered since that time. This indication of a cir- with an opposing force in the shape of resistance, colar motion by the Gulf Stream is corroborated sufficient in the aggregate to retard it two miles by the bottle chart and other sources of informa- and a half the minute, and this only in its Easttion. If, therefore, this be so, why give the end- wardly rate. There is, doubtless, another force less current a higher level in one part of its course quite as great, retarding it towards the North, for than another?

its course shows that it is the resultant of two Nay more. At the very season of the year forces acting in different directions. If the former when the Gulf Stream is rushing in greatest volume resistance be calculated according to received laws, through the straits of Florida and hastening to the it will be found equal to several atmospheres. North with the greatest rapidity, there is a cold And by analogy, how inadequate must the pressure stream from Baffin's Bay, Labrador, and the coasts of the gentle trade winds be to such resistance, of the North, running to the South with equal ve- and to the effect assigned them? If, therefore, in locity. Where is the Trade wind that gives the the proposed inquiry we search for a propelling high level to Baffin's Bay, or that even presses upon power no where but in the higher level of the Gulf, or assists to put this current in motion? The agency we must admit, in the head of water there, the erof winds in producing currents in the deep sea must istence of a force capable of putting in motion and be very partial. These two currents meet off the of driving over a plain, at the rate of 5 miles the Grand Banks, where the latter is divided. One part hour, all the waters as fast as they can be brought of it underruns the Gulf Stream, as is shown by the down by 3,000 such streams as the Mississippi icebergs which are carried in a direction tending river-a power at least sufficient to overcome across its course. The probability is, that this the resistance required to reduce from two miles “ fork” continues on towards the South and runs into the Carribbean Sea, for the temperature of the

* In this calculation the earth is treated as a perfect water at a little depth there, has been found far aphere, with a diameter of 7925.56 miles. below the mean temperature of the earth, and quite

† Or 915,26 to 758,60. On the latter parallel, the ent

rent has an East set of about 14 miles the hour--making as cold as at a corresponding depth off the Artic the true velocity to the East and on the axis of the earth shores of Spitsbergen.

about 760 miles the hour at the Grand Banks.

and a half to a few feet per minute, the velocity verted, spiral turning towards the West. Owing of a stream that keeps in perpetual motion one to the principle here alluded to, all currents from fourth of all the waters in the Atlantic Ocean. the Equator to the poles should have an Eastward

The facts, from observation on this interesting tendency, and all from the poles towards the equasobject, afford us at best, but a mere glirnmer of tor, a Westward. light, by no means sufficient to make my mind clear Let us now suppose the solid nucleus of this as to a higher level* of the Gulf, or as to the suffi- hypothetical globe to assume the exact form and ciency of any other of the causes assigned for this shape of the bottom of our seas and in all respects, wonderful stream. If it be necessary to resort to as to figure and size, to represent the shoals and isa higher level in the Gulf, to account for the velo- lands of the sea, as well as the coast lines and concity off Hatteras, I cannot perceive why we should vinents of the earth. The uniform system of curnot, with like reasoning, resort to a higher level rents just described would now be interrupted by off Hatteras also, to account for the velocity off obstructions and local causes of various kinds, the Grand Banks ; and thus make the Gulf Stream, such as unequal depth of water, contour of shore throughout its circuit, a descending current, and lines, &c.; and we should have, at certain places, by the reductio ad absurdum, show that the Trade currents greater in volume and velocity than at winds are not adequate to the effect ascribed. others. But still there would be a system of cur

When facts are wanting, it often happens that rents and counter currents to and from either pole bypothesis will serve, in their stead, all the pur- and the equator. Now do not the cold waters of poses of illustration. Let us, therefore, suppose a the North, and the warrn waters of the Gulf made glube of the earth's size, having a solid nucleus specifically lighter by tropical heat, which we see and covered all over with water 200 fathoms deep! actually preserving such a system of counter curand that every source of heat and cause of radia- rents, hold, at least in some degree, the relation tion be removed, so that its fluid temperature be- of the supposed water and oil. comes constant and uniform throughout. On such a Apparently, in obedience to the laws here hinted globe, the equilibrium remaining undisturbed, there at, there is a constant tendency of polar waters would be neither wind nor current. And the poet's towards the tropics and of tropical waters towards picture would apply to every sea :

the poles. The Exploring Expedition crossed one “ Still as a slave before his lord

of these hyperborean currents 200 miles in breadth The Ocean hath no blast;

at the equator. There is also one near our own His great bright eye most silently

coast, another on the West coast of South America, Up to the moon is cast.”

as well as several others elsewhere known to exist; Let us now suppose that all the water within the

but for obvious reasons they are, for the most part, tropics, to the depth of 100 fathoms, suddenly be

submarine and but little understood.

Counter to these are the Gulf Stream and the comes oil

. The aqueous equilibrium of the planet Lagullas current, besides numerous others more is thereby disturbed, and a general system of currents, and counter currents is immediately com

gentle and partial and therefore less marked in menced-the oil in an unbroken sheet on the sur

their character. But why one of these currents face running towards the poles, and the water in an

should always run from the Gulf of Mexico and under current, towards the equator. The oil is

the other along the coast of Africa, seems to desupposed, as it reaches the polar basin, to be re-con

mand the presence of other agents. Perhaps these Terted into water, and the water to become oil as may be found in local causes, such as the contour it crosses Cancer and Capricorn, rising to the sur

of coasts, the constant force of Trade winds, high face and returning as before.

temperature of the Gulf, &c. These would give Thus, without wind, we should have a perpetual tial velocity of the Gulf Stream.

the first impulse, and may be adequate to the iniand uniform system of tropical and polar currents. In consequence of diurnal rotation of the planet on

Assuming its maximum velocity at 5 knots, and its axis, each particle of oil, were resistance small,

its depth and breadth in the Narrows of Bemini,

as before, the vertical section across would prewould approach the poles on a spiral turning to the

sent an area of two hundred millions of square East, with a relative velocity greater and greater, feet moving at the rate of 7 feet 3 inches per until, finally, it would reach the pole and wbirl

second. The difference of specific gravity between about it at the rate of nearly a thousand miles the

the volume of Gulf water that crosses this sectional hour. Becoming water and losing its velocity, it would approach the tropics by a similar, but in

line in one second, and an equal volume of water

at the ocean temperature of the latitude, is fifteen The Gulf, or Carribbean Sea, may have, towards the millions of pounds. If these estimated dimenchannel of Yucatan, a higher level of a few inches and such sions (assumed here—as throughout this paper they only as is due to any other large stream of 3 or 4 knots when deflected in its course, as the Carribbean currents

have been-upon the best authority, but merely are, between their entrance into that sea and their exit for the purposes of illustration,) be within limits, from the Gulf.

then the force per second, operating here to propel

VOL. X-51

the waters of the Gulf towards the pole, is the as from other circumstances. If it did, the upper equilibrating tendency due to 15 millions of pounds edges of ils cold banks would support a lateral of water in the latitude of Bemini.

pressure of at least 100 lbs to the square foot; and In drawing up a plan for investigating the currents vessels, in crossing it, would sail over a ridge as of the seas, such agencies should be taken into ac- it were; on the East side of which, they would count. As a cause, I doubt whether this one is suf- meet an Easterly current; and on the West side, ficient of itself to produce a stream of such great a Westerly current. The resolution of the forces velocity as that of the Gulf; for, assuming its es- of each of these currents, with the Northwardly timated discharge to be correct, the proposition is set of the stream itself, would induce Navigators almost susceptible of mathematical demonstration, to report a North Eastwardly current as they asthat to overcome the resistance opposed in conse- cend the other side of this ridge, and a North Westquence of its velocity, would require a force at wardly current as they descend on this; yet never least sufficient to drive, at the rate of 3 miles the was it heard that the Gulf Stream runs North hour, ninety thousand millions of tons up an in-West. clined plane, having an ascent of 3 inches to the Should this roof current be too superficial to mile.* Yet the very principle from which this be felt by a vessel, the Gulf weed and all the agent is derived, is adınitted to be one of the chief floating substances borne by the stream across causes of those winds which are said to be the sole the Atlantic would run off on either side. But cause of this current.

there is little or no Gulf weed along it WesBut, in addition to this, may there not be a pe- tern edge, and its prevalence on the Eastern side culiar system of laws not yet revealed, by which may be readily accounted for by the operation of the motion of Auids in such large bodies is govern- quite another law. Why this warm water thereed when moving through each other in currents of fore should not appear lighter than cold water is different temperature. That currents of sea water, a curious phenomenon that, as far as I know, has having different temperatures, do not readily com- never been considered. It is worthy of investimingle, is shown by the fact already mentioned: that gation. Nor should the paradox as to a higher the line of separation between the warm waters of level—a double inclined plane in the Gulf Stream the Gulf and the cold waters of the Atlantic is itself, escape attention. Dr. Lardner assures us, perfectly distinct to the eye for several hundred and such too is the doctrine not yet exploded from miles; and even at the distance of a thousand our popular works,* that sea water expands accordmiles, though the two waters have been in contact ing to the laws of fresh ; and from this circnmand continued agitation for many days, the ther-stance he argues that the fish in polar seas are premometer shows that the cold water on either side served by the cold water being on top and the still performs the part of river banks in keeping warmer below. But deep sea soundings do not the warm waters of the stream in their proper confirm this. With a surface temperature of 31°, channel.

Northern voyagers have obtained a temperature at In a winter's day off Hatteras, there is a differ- the depth of several hundred fathoms of 25°, which, ence between these waters of near 20°. Those according to the received laws of expansion, should of the Gulf being warmer, we are taught to be have the specific gravity of water at 55°. And a lieve that they are lighter; they should therefore thermometer thrust down the throat of a fish caught occupy a higher level than those through which in polar seas, has been said to stand at Zero. The they float. Assuming the depth here to be 114 journals of arctic cruizers assure us of the fact, fathoms, and allowing the usual rates of expansion, that the deeper we go down in the Northern seas figures show that the middle of the Gulf Stream of America, the colder the water, while the warmth here should be nearly 2 feet higher than the con- off the shores of Northern Europe increases as tiguous waters of the Atlantic. Were this the we go down; thus showing a warm stratum of case, the surface of the stream would present water to be lighter than the cold in one part of the double inclined plane, from which the water would Ocean, and in another contiguous to it, to be heabe running down on either side, as from the roof vier. of a house. As this ran off at the top, the same But to return to the mingling of the waters.weight of colder water would run in at the bottom; We know from a familiar experiment, that oil and thus, before this mighty stream had completed placed on water in a state of rest exerts an obrihalf its course, its depths would be brought up to ous and sensible force to put itself in motion; and the surface, and its waters would be spread out it is a fact well known to iron founders, that cold over the ocean. Why then does not such a body and therefore heavier iron, I will not sink in the of warm water, flowing and adhering together * Dr. Marcet shows that sea water contracts until i through a cold sea, obey this law, and occupy

freezes.

+ If a bit of paper cut in the shape of a comma be dipped higher level ? That does not, we may infer from in oil and laid on water, the oil, in running off, will eause the silence of Navigators on the subject, as well the paper to spin round.

I A cannon ball dropped into a ladle of melted iron will * Supposing there be no resistance from friction. not sink till it expands, grows red hot, and becomes lighter.

a

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