Transactions of the Asiatic Society of Japan/Series 1/Volume 1/The Typhoons of September and October, 1872
THE TYPHOONS OF SEPTEMBER AND
OCTOBER 1872,
BY
Lt.-Commander NELSON, U. S. War-ship “Idaho,”
Read before the Asiatic Society of Japan,
on the 10th May, 1873.
———o———
Nearly two centuries ago there were accounts published of ships having scudded (run before the wind) in a hurricane for a day or two, and yet found themselves very nearly in the place from which they started when the gale commenced; and of others which in lying to, had the wind veering rapidly and sometimes shifting suddenly to an opposite point of the compass, the shift most generally preceded by a calm, but not always so; and again of other ships which, though not far distant from each other, had the winds blowing furiously in opposite directions and veering differently.
Yet no one appears to have attempted to solve this, at that time, strange problem or to account in any way for the singular phenomenon (that used to puzzle the understanding of the hardy old Tars who having passed successfully through one of these storms escaped with their lives to tell the tale of their experience) until nearly one-third of the present century had passed away.
I would not be understood to say that no one had ever given any attention to the subject—for I propose to cite authorities by whom these storms had been noticed and pronounced to be great whirlwinds—but I mean to assert that no one had ever attempted to solve the problem by pursuing their investigations, and generalizing observed facts in order to clear up the mystery and discover the laws by which these storms are governed up to the time I have mentioned.
In the year 1698 Captain Langford in a paper on the West Indian Hurricanes (Philosophical Transactions for 1698) describes the veering of the wind and calls it a whirlwind, speaks of a progressive motion and gives it some limits but nothing more.
In the year 1743 a Spanish navigator Don Juan De Ulloa describes a storm on the Pacific Coast of South America, in which description he speaks of the veering and sudden shifting of the wind, but does not seem to have conceived the idea of a whirlwind or rotatory storm.
Colonel Capper—in speaking of the Madras and Coromandel Coast hurricanes—says, in a work published in 1801 after describing these storms:—“All these circumstances properly considered clearly manifest the nature of these winds, or rather positively prove them to be whirlwinds whose diameter cannot be more than 120 miles, and the vortex seems generally near Madras or Pulicat;” and again after describing some on the Malabar Coast, and in the Southern Indian Ocean he says:—“Thus then it appears that these tempests or hurricanes are tornadoes or local whirwinds, and are felt with at least equal violence on the Coast and some little distance out at sea.”
A French author named Romme in a work published in 1806, describes a storm in the China sea near the Gulf of Tonkin, which he distinctly calls a whirlwind, and applies the same name to other storms experienced in the Mozambique Channel, and again others in the Gulf of Mexico.
Professor Farrar of the Cambridge University, New England, in describing a storm that passed over Boston in 1815 says that he could not determine the centre or limits, but noticed the veering of the wind and the fact of it having veered in opposite directions at Boston and New York at the same time. Also the difference of time between the greatest violence of the storm at the two places.
But it is not my purpose here to cite all the cases on record of gales that have attracted the attention of scientific men. Enough has been said to show that such men did notice the peculiar character of these storms and to some extent explained it by deciding that they were great whirlwinds. None of them, however, followed up the clue thus found, or attempted to unlock the secret of the Law, to which this was evidently the key until the year 1831, when Mr. William Redfield, an American Philosopher and Naval Architect, came out in a paper published in the American Journal of Science, and clearly demonstrated that the storms on the American Coast were not only rotatory storms or blowing in circles around a common centre, but also that they had a progressive motion and were traceable moving on a curved track, from the West Indies and along the Coast of the United States, curving off to the Eastward near the banks of Newfoundland. At the same time he published some excellent rules for avoiding the centre, and the chances of damage to ships caught in these gales at sea, showing also how the barometer might be made a valuable guide if carefully watched and properly attended to.
While Mr. Redfield was employed collecting the information upon which he based his theory of the law of storms, a similar investigation was going on in Germany.
A number of gales had attracted the attention of German Meteorologists chiefly on account of the oscillations and great fall of the barometer before and during these gales; and a Mr. Brande who had kept an accurate register of observations for a length of time, and obtained the registers kept in various places at the same time, eventually advanced a theory that the wind, during these great storms, blew from all points of the compass in straight lines towards a central space where the barometer was for the time at its lowest stand.
The theory of Mr. Brande was disputed by Professor Dove of Berlin who subjected the observations to a new examination, and made it appear that an explanation of all the phenomena was afforded by the assumption of one or more circular currents, or whirlwinds of great diameters, advancing from South West to the North East.
The theory of Professor Dove although under discussion about the same time when Mr. Redfield by an independent course of investigation arrived at the results abovementioned, was not known in the United States when the latter gentleman published his paper in the American journal of science, a fact indicated strongly in the language of Sir David Brewster when he said: “The theory of rotary storms was first suggested by Colonel Capper but we must claim for Mr. Redfield the greater honor of having fully investigated the subject, and apparently established the theory upon an impregnable basis.”
In the year 1838, Lieutenant-Colonel Reid of the Royal Engineers published a valuable work entitled “Reid on the law of storms,” in which he agreed in all particulars with the views of Redfield, and verified by personal observation all his theory; adding many substantial proofs to the same by investigations of West Indian hurricanes, and of some in the Southern Indian Ocean. Colonel Reid by his observation of storms in the Southern Indian Ocean further proved Mr. Redfield’s theory that the storms in the Southern Hemisphere revolve in a contrary direction to those in the Northern Hemisphere. Colonel Reid may be said to have reduced the science to practical use by showing how safe rules for scudding, or lying-to in a hurricane, might be deduced from the theory, and how when obliged to lie-to, ships should do so on the proper tack according to the side of the path they are on; and lastly how these storms may be made profitable to ships bound in the direction of their track, by sailing carefully on the outer circumference with a fair wind, being all the time in a safe position to heave-to and let the storm pass.
Thus by the publication of Col. Reid’s “Law of Storms” the science was reduced from a mere speculative theory to a practical law, the value of which can be fully appreciated only by the mariner when caught in one of these gales at sea.
That which had been discovered by Mr. Redfield and verified by a great number of observations by Col. Reid has been termed the Law of Storms, and is briefly explained as follows:—If by reference to the Diagram we suppose the short curved arrows to represent the direction of the wind, and the long dotted arrow to indicate the track or course on which the gale is moving bodily forward, we shall have before us the Law of Storms in the Northern Hemisphere; and by reversing the whole, that is turning the points of the arrows in the opposite direction, the diagram will represent the Law of Storms in the Southern Hemisphere.
Mr. Peddington says in speaking on this subject. The words “Law of Storms,” then, signifies first;—that it has now been proved by the examination and careful analysis of perhaps more than two thousand logs and of some hundreds of storms by the authors already referred to (Redfield, Reid, Dove and others) and by many other observers in periodical publications; as well as some whose results have not yet been published, that the wind in hurricanes, and frequently in severe storms in the higher latitudes on both sides of the Equator, has two motions. It turns or blows round a focus or centre in a more or less circular form, and at the same time has a straight or curved motion forward, so that, like a great whirlwind, it is both turning round and, as it were, rolling forward at the same time.
Next it is proved that it turns, when it occurs on the North side of the Equator, from the East or the right hand by the North towards the West, or against the hands of a watch (as represented by this diagram), and in the Southern Hemisphere that its motion is the other way or with the hands of a watch;—being thus as expressed by Professor Dove of Berlin, South, East, North, West, for the Northern Hemisphere; and North, East, South, West for the Southern Hemisphere.
These two principal laws, (turning round a centre and moving forward), constitute the rule or law of storms, and it has been abundantly demonstrated to hold good for several parts of the world; but as we do not have positive evidence from all parts of the world it is assumed that this law is true everywhere, and this assumption is based upon the strongest grounds, viz:—the great analogy usually existing in the laws of nature, and the fact that every new investigation affords fresh proofs of the truth of the law in both hemispheres.
Having thus established the law of motion of the winds in a tpyhoon, we have only to consider whether we are north or south of the equator in order to locate the centre; if north we know that the winds rotate from right to left, contrary to the watch hands, or from S. to E. by N. to W., and also that the N. compass point is the E. typhoon point, that is the wind blows East.
The W. compass point is the N. typhoon point, the S. compass point is the W. typhoon point, and the E. compass point is the S. typhoon point; hence, to locate the centre as to bearing or direction, stand in the middle of a compass (or imagine such a thing) and look towards the typhoon point, or in the winds eye, and the centre will be on the right hand, and to prove this strike off a small circle and let the circumference represent the wind circle in a typhoon; then draw a straight line through the centre of the circle so as to cut the wind-circle, and it will do so at right angles. Draw another line through the centre, at right angles to the first, and it will be found at a point 90 degrees to the left of the first line or where the second line cuts the wind-circle. The direction of the wind will be parallel to the first line; hence, standing at this point and looking in the direction of the wind’s eye, and parallel to the first line the centre will be 90 degrees to the right, or on the right hand.
As a practical example I will take the typhoon which passed over Yokohama on August 25th, 1872, and which this diagram is intended to represent. The wind in the commencement of this gale was E. S. E., and according to the above rule of looking into the wind’s eye and having the centre on the right hand, in this case it ought to bear S. S. W., and this was exactly the case as shown by this diagram, the “Idaho” at her anchorage in the harbour being marked on the N. N. E. part of the circle.
As most of you here present were in Yokohama at the time when this typhoon passed over the place it will not be necessary to dwell long on the details of it, especially as there was nothing very remarkable about it. I will merely mention such of the principal facts as may be of interest to those of you who had no opportunity of observing them for yourselves.
Thus: at 4 p.m. the gale commenced with the wind at E. S. E., blowing with a force of from 6 to 9; barometer 29.28; thermometer 80; weather, o. c. q. r. n.; clouds, cumulus-nimbus; sea m.
At 5 p.m., wind E. S. E., force from 9 to 10; barom. 29.14, having fallen 0.14 inch during the hour; therm. weather and clouds the same; sea c. r. At 6 p.m. E. S. E. 14 E., force 9 to 11; barom. 28.94, having fallen 0.20 during the hour; therm. 78, at 7 p.m. E.S.E.12 E., force 1112. This was a fearful blast which lasted about five minutes; had it continued for any length of time great damage both on shore and in the bay would have been the inevitable results. Even during the short time it did last two vessels were started from their anchorage and driven rapidly before the fury of the blast. One, a small steamer, which in her course fouled a native junk and sunk her; the other, a British barque, drifting at the rate of about five or six knots in a W. N. W. direction towards the Kanagawa shore where she would surely have brought up had the wind continued for half an hour, or even 20 minutes longer. Barom. at 7 p.m. 28.50 having fallen O.44 inch during hour. At 7.05, however, the blast was over and the wind began to veer to the southward.
At 7.15, barometer 28.35, having fallen 0.15 inch in 15 minutes, wind S. very light, the rain and squalls had ceased and an entire calm followed. At 7.30 barometer had reached its lowest stand 28.27, having fallen 0.08 inch during the 15 minutes, and at that time I compute the centre to have passed over the “Idaho”; the calm lasted for nearly half an hour. At 7.45 light airs were felt from N. W., and at 8.00 the shift came, in force from 7 to 9 from W. N. W. 12 W. with a re-appearance of heavy rain and violent squalls; the barometer had risen to 28.32. At 9 p.m., the wind was W. by N. barometer 28.70, showing a rise of 0.38 inch during the hour; the wind blew with a force of from 8 to 10. At 10 the wind was nearly W., force from 4 to 6; barom. 28.93, showing a rise of 0.23 during the hour; the rain at this time ceased. At 10.15 the blue sky appeared; and at 11 p.m. the typhoon had entirely passed away, and the barometer had risen to 28.99.
This diagram shows the centre to have passed over this place, and this is made evident (in accordance with the law) by the wind remaining nearly stationary during the first half of the gale, a thing which can only occur when the centre is travelling directly towards you, or when running on a course parallel to the course of the “Typhoon”—keeping the bearing of the centre the same as with the bearing of the centre, the wind must always change.
Take for an example this typhoon travelling N.E. instead of N.N.E., or at an angle 2212° to the first line of bearing of the centre as observed at the beginning of the Typhoon—the centre in that caxc would not have passed over Yokohama but about 20 miles to the Eastward, and the winds would have changed as follows: commencing at 4°° E.S.E.—as it was—at 5°° wind would have been E. by S., at 6°° E.N.E., at 7°° N.N.E. nearly, at 8°° N. by W. 14 W., and at 9°° N.N.W. 14 W., at which time the storm-circle would have left us, and we should have passed through the cord of an are equal to 138° of the storm circle, and the length of that cord would have been equal to about 98 miles. I have computed the diameter of this typhoon to be 105 miles, the whole diameter requiring seven hours to pass a given point, travelling at the rate of 15 miles an hour. The diameter and rate of travelling is arrived at by knowing the time occupied in passing over a space of 15 miles from a point in the vicinity of Cape Kamisaki to the Idaho’s anchorage in this harbour.
The general course of this typhoon was N.N.E. curving more to the Eastward after passing here.
The greatest fall of the Barometer in one hour was 0.44 inch, and the total fall was 1.01 inches.
I will now briefly state a few of the theories afloat regarding the origin or cause of Circular Storms, (Typhoons.) Although none of the scientific men who advance these theories pretend to say that they are correct—or even approximately so—there is nothing positive known about the origin or cause of typhoons, and the theories at best are only probable ones. Thus Mr. Redfield seems to think they are produced by the conflicts of prevailing currents in different strata of the atmosphere, giving rise to circular movements, which increase and dilate to storms.
Colonel Reid thinks there may be some connection between electricity, magnetism and these storms.
Mr. Espy, an American Philosopher, has published a work (entitled “Philosophy of Storms”) in which he gives one of the causes of storms as follows:—Upon any partial heating of the air at the surface of the Earth, it rises in columns more or less charged with vapor, condensed into clouds or rain. Next, in this changing of state the vapor communicates its latent caloric to the surrounding air, which also expands, is cooled itself by that expansion, but also gives heat to that part of the air in which it then is, and becoming lighter, is carried farther up. So that which Mr. Espy calls an upmoving column is always thus formed before rain is produced, and the air rushing in to supply the partial vacuum at the base of this chimney-like column forms thus the centripetal streams of air which he affirms is the true motion of the wind in all storms, and especially in typhoons; and according to his theory the winds do not blow in circles, but are straight lined and blowing from the circumference of a circular storm disc towards the centre, rushing up an immense moving chimney of any longitudinal shape, the draught of which is occasioned by an extensive condensation of vapor above.
He accounts for the production of clouds, the rise and fall of the Barometer by this cause, inferring, that at a certain height the rising air overflows the rest of the atmosphere, forming a ring of cloud vapor and air, which pressing on that below, occasions the rise of the barometer found at the edges of severe storms.
Mr. Thomas Hopkins of Manchester, in a work published in 1844, entitled “On the atmospheric changes which produce Rain, Wind and Storms,” admits with Mr. Espy the ascent and condensation of vapor in the air from various causes, and that all horizontal winds are thus produced. He considers also that the ascending winds produce descending ones, and that the rain produced in the higher regions brings air and vapor with it in its descent, and thus constitutes the lower atmospheric currents; and finally, that storms are produced by the same causes that produce other winds, and that the greatest storms are descending winds.
Dr. Alex. Thom., of H. M. 86th Regiment, in his book upon “Storms in the Indian Ocean, and South of the Equator,” is of opinion, that the cause of the rotatory motion in storms—is, at first, opposing currents of air on the borders of the monsoons and trade-winds, which differ widely in temperature, humidity, specific gravity, and electricity. These, he thinks, give rise to a revolving action which originates the storm, which subsequently acquires an intestine and specific action involving the neighboring currents of the atmosphere, and enabling the storm to advance through the trade-winds to its opposite limits.
He further inclines to believe that “as the external motion is imparted to the interior motion of the mass, and centrifugal motion begins to withdraw the air from the centre and form an up-current, the whole will soon be involved in the same vortical action.” The up-current he accounts for by the pressure being removed from the centre, when the air there increases in bulk, diminishes in specific gravity, and hence its upward tendency.
There is, however, another point of view in which some writers have considered the formation and continuance of these storms. They suppose, with Dr. Thom, that the storms are formed by opposite currents of air, producing whirlpools as in water, but do not consider with him, that they are produced at the edges of the streams, as we see in water whirlpools. These writers incline to the belief that the whirls originate between the upper and lower surfaces of strata of air of different temperatures, degrees of moisture &c. and moving in different directions.
These whirls, they suppose, first formed above, and then descend to the surface of the earth; just as we see a water spout begin at sea, with a slight swelling of the lower part of a cloud, and then a gradual descent of it. In short, they look upon typhoons as wind-spouts.
The views of Sir John Herschel on the causes of typhoons may be briefly stated, as follows:—
It seems worth inquiry, he says, whether hurricanes in tropical climates may not arise from portions of the upper currents prematurely diverted downwards before their relative velocity has been sufficiently reduced by friction on, and gradually mixing with, the lower strata; and so dashing upon the earth with that tremendous velocity, which gives them their destructive character, and of which hardly any rational account has yet been given.—Their course, generally speaking, is in opposition to the regular trade-wind, as it ought to be in conformity with this idea.
He then goes on to say—but it by no means follows that this must always be the case—In general, a rapid transfer, either way in latitude, of any mass of air which local or temporary causes might carry above the immediate reach of the friction of the Earth’s surface would give a fearful exaggeration to its velocity. Wherever such a mass should strike the Earth a hurricane might arise; and should two such masses meet in mid-air, a tornado of any degree of intensity on record might easily result from their combination.
Sir John Herschel further suggests that two great atmospheric undulations (which he terms barometric waves, because they are made evident by the fluctuations of the barometer) travelling in opposite directions and intersecting each other, from their opposing forces might cause the phenomena of hurricanes or rotary storms.
Mr. Peddington says in his valuable work on storms entitled the “Sailor’s Hornbook,” page 22, par. 38, with reference to the cause or origin of typhoons:—“My own views are that cyclones (cyclone is the word which Mr. Peddington adopted to express the idea of a circular storm, and which is now generally accepted and used by nautical people) are purely electric phenomena, formed in the higher regions of the atmosphere, and descending in a flattened disk-like shape to the surface of the Ocean, where they progress more or less rapidly.” “I think that the whirling tornadoes, spouts, and duststorms, are certainly connected with them; i.e. that they are the same meteor in a concentrated form, but we cannot at present say where the law which regulates the motions of the larger kind, ceases to be an invariable one.”
Some writers advance the idea that Volcanoes—and even large fires—originate violent circular motions of the atmosphere; and that volcanic eruptions are often accompanied by violent storms and heavy falls of rain there is no doubt. Mr. Peddington says: “there is much to countenance the idea that cyclones in some parts of the world may originate at great volcanic centres,” and he is inclined to believe that their tracks are partly over the great internal chasms of our globe by which perhaps the volcanic centres and bands communicate with each other. He then goes on to say:—“if we produce at both ends the line of the track of the great Cuba cyclone in 1844, we shall find that it extends from the great and highly active Volcano of Cosseguina, on the Pacific shore of Central-America, to Hecla in Iceland.” In 1821 the breaking out of the great Volcano of Eyafjeld Yokul in Iceland which had been quite since 1612, was followed all over Europe by dreadful storms of wind, hail, and rain. In Iceland the baromemer fell from the day before the eruption and for several days after.
A well authenticated fact was published in the English newspapers in 1852, of an extraordinary marine convulsion experienced by the British ship Mary, on her passage from Liverpool to Caldera, being 12 miles North of the equator, in long. 19° W. A rumbling noise was heard to issue from the Ocean, which gradually increased until the uproar became deafening. The sea rose in mountainous waves; the wind blew from all points of the compass; the control over the ship was lost, and she pitched frightfully, all on board expecting every moment to be their last. This continued 15 minutes, the water then gradually subsided, when several vessels, in sight at the commencement of the convulsion, were found to have disappeared. It is noteworthy that the phenomenon occurred in October 1851, one of the hurricane months in the West Indies.
Typhoons seldom appear without giving notice of their approach, and some indications may almost be relied on as being sure messengers of warning. Among the principal of these is the barometer. Not unfrequently upon the approach of a typhoon, the barometer seems restless and the mercury keeps oscillating in the tube:—often, when on the borders of a typhoon, the barometer rises suddenly one or two tenths; and Col. Reid gives an instance where two barometers on board the same ship rose half an inch above their usual level. If these indications by the barometer should be accompanied by a long, heavy swell, unaccounted for in any other way; an unusual appearance of the sky steel-grey or with a greenish tint; blood-red, or bright yellow sunset: and, added to these, the appearance of peculiar or unusual forms or motions of the clouds, or a threatening appearance of the weather, I should have no hesitation in asserting that a typhoon was in the vicinity, approaching or passing; but either one of these things—taken separately—ought not to be disregarded, and the careful seaman will always be on his guard should any of these things appear to warn him of approaching danger. Mr. Peddington relates the case of the “Earl of Hardwicke”, Captain Neller, as follows:—
“In the Southern Indian Ocean, when near the borders of a typhoon, she was standing off and on to keep out of it; and describes the weather as being squally, thick, heavy and wild looking; the upper clouds coming from N.W.; the next stratum N.E.; and the lower scud, with the wind, fast from S.E. The trades (S.E.) were blowing strong—but at midnight ran into a dead calm; the breeze soon sprung up again, and the next day had a high, confused sea, barometer rising from 29.95 to 30.00. For two days after, the barometer kept falling gradually, squally weather, but strong trades. On the third day, barometer had fallen to 29.71, ship hove to, the appearance of the weather was threatening; dense lurid atmosphere; very peculiar appearance at sunset, last two evenings. Dark and threatening appearance to the N.Wd.; the wind increasing and drawing to the E’d., with thick weather when standing to the N’d., but always fine when going S. A thick, lurid appearance over the heavens—the sun only showing as through a dense veil, with heavy leaden-looking clouds to the N. and N.W.”—He further states: “The weather became more squally, with rain, when standing N.—and that one heavy squall from N.E. was followed by light airs from the E’d. In some of the squalls the clouds were so dense and dark that it was not possible to see further than fifty yards from the ship.” He also speaks of immense masses of leaden-colored clouds, covering the whole canopy of heaven, and giving it a murky, threatening appearance, and the sun setting, casting over the whole a red, lurid appearance, and throwing over everything on board the ship a reddish tint.
I have selected this case as a good example of what the indications of typhoons are, and although all typhoons are not as well marked as this one, yet one or more of these signs will generally appear in advance of the gale; and, separately or collectively, should receive a proper degree of consideration, as much of the safety of the ship and crew depends upon timely measures being taken for avoiding the gale, or if that be not possible, at least the dangerous part of it. In connection with the signs of approaching gales, I would mention that several cases are recorded wherein have appeared peculiar red tints, or lights in the heavens, described as—“Flaming clouds on the horizon from whence proceeds the fiery tempest”; “appearing like entire conflagrations of the air and seas.”—And on other occasions “appearing as borders round the edges of remarkably dense and dark clouds, reflecting an awful redness upon the sails and ship.”
A number of similar cases are recorded which show that this red light and sky is not an uncommon phenomenon, or precursor, of typhoons.
Nearly all writers agree that a typhoon is a circular storm-disc varying from one to ten miles in height, and in diameter from fifty to one thousand miles; and that the winds within the disc blow in circles—or nearly so—round a common centre, which is generally calm, and varying in size from one tenth to one fifth, and in some cases as much as one-fourth, of the whole diameter of the gale.
Writers as we have seen differ as to the place of formation, or commencement, of these gales. Some asserting with Dr. Alexander Thom that they are formed on the borders of the trade winds and monsoons; and others, with Messrs. Redfield and Peddington that their motion is caused by opposing currents meeting in mid-air, and differing in temperature, humidity, electricity, &c., &c.
Col. Reid suggests that electricity and magnetism have something to do with the formation and continuance of these gales; and Mr. Peddington says they are, in his opinion, purely electrical phenomena.
Now, if we consider the theory of the mid-air formation of circular gales, and imagine two currents of air of different temperatures, degrees of moisture, and charged respectively, with positive and negative electric fluids (the well known properties of which are to attract each other) travelling in opposite directions, it is probable that the meeting of these unequal and opposite forces, in the act of seeking or establishing an equilibrium, may have a rotary motion imparted to them; the first particles in meeting having become neutralized and formed a focus round which the remaining currents commence to move with great rapidity, and so impart their motion to the surrounding atmosphere, which, in its turn, performs the same duty, and soon a large portion of the atmosphere becomes involved in the same vorticular action. An extensive condensation of vapor going on in the centre, the air becomes lighter there than elsewhere in the revolving disc, and forms a kind of chimney for the denser air below to pass up through; and when this process has been going on for some time the air beneath is sufficiently exhausted to admit of the storm disc descending to the surface of the earth, after reaching which, it takes up a progressive motion and is impelled by magnetic attraction towards the magnetic poles.
A seeming contradiction to this statement may be found in the “Argyleshire’s” Typhoon, which I have here represented as travelling W. by S., and in a direction nearly parallel to the Magnetic Equator; but when it is remembered that some portions of the earth are heavily charged with magnetism (as is shown by the variation of the mariner’s compass to the extent of two points or more of deviation from the true Meridian, and especially in the Danish Sound and Baltic Sea, where the local magnetic forces in the adjoining countries—especially Sweden, where iron is found in great quantities—is so great as to attract the compass very much more) it may be quite possible that similar attractions exist in China, or on the island of Hainam which is called by the Chinese “the Mother of Typhoons.”
I am aware, while supporting Col. Reid’s theory of magnetism in typhoons, that opinions and theories have been published in opposition to it; but none have proved it to be wrong, or have accounted more clearly for the progressive motion of circular gales; and as all theories as yet made known with regard to the origin and cause of circular gales are but speculative in their character, I see no reason why the theory of magnetism in connection with typhoons should not receive a fair share of consideration, and as far as I am personally concerned, I give it the preference.
Some writers are of opinion that there is a close connection between whirlwinds, dust-storms, and circular gales, and go so far as to say that whirlwinds and dust-storms are but miniature typhoons.
I will cite a few cases of this kind which (if electricity be considered one of the agents in the production of circular gales) certainly proves to some extent that the idea is not altogether unfounded.
I quote from Mr. Peddington’s work, page 303, where will be found the following report by Dr. H. P. Baddeley, H. E. I. C. S., dated from Lahore, showing by experiments that the dust storms are purely electrical.
“My observations on this subject have extended as far back as the hot weather of 1847 (this was written in 1850 in the “Philosophical Magazine” for August) when I first came to Lahore; and the result is as follows:—Dust storms are caused by spiral columns of the electric fluid passing from the atmosphere to the Earth. They have an onward motion and a revolving motion, like revolving storms at sea, and a peculiar spiral motion from above downwards like a cork-screw. It seems probable that in an extensive dust-storm there are many of these columns moving on together in the same direction; and during the continuance of the storm many sudden gusts take place at intervals, during which the electric tension is at its maximum.
These storms hereabouts mostly commence from the N.W. or W. and in the course of an hour—more or less—they have nearly completed the circle, and have passed onwards.
Precisely the same phenomena, in kind, are observable in all cases of dust-storms; from the one of a few feet in diameter, to those that extend for fifty miles and upward, the phenomena are identical.
It is a curious fact that some of the smaller dust-storms—occasionally seen in extensive and arid plains, both in this country and in Affgghanistan above the Bolan Pass, called in familiar language “Devils,”—are stationary for a long time, that is upwards of an hour, or nearly so, and during the whole of this time the dust and minute bodies on the ground are kept whirling about in the air.
In other cases these small dust-storms are seen slowly advancing, and when numerous, usually proceed in the same direction.
Birds—Kites and Vultures—are often seen soaring high up, just above these spouts, apparently following the direction of the column, as if enjoying it.
My idea is that the phenomena connected with dust-storms are identical with those present in waterspouts and white squalls at sea and revolving storms and tornadoes of all kinds; and that they originate from the same cause viz—moving columns of electricity.”
In 1847, at Lahore, being desirous of ascertaining the nature of the dust-storms, I projected into the air an insulated copper wire on a bamboo on the top of my house, and brought the wire into my room, and connected it with a gold-leaf electrometer and a detached wire communicating with the earth. A day or two after, during the passage of a small dust-storm, I had the pleasure of observing the electric fluid passing in vivid sparks from one wire to the other, and of course strongly affecting the electrometer. The thing was now explained, and since this, I have, by the same means, observed at least sixty dust-storms of various sizes all presenting the same phenomena in kind.”
He continues to describe the dust storm as follows:—“Some of them come on with great rapidity, as if at the rate of forty to sixty miles an hour. They occur at all hours, oftentimes near sunset.
The sky is clear and not a breath moving: presently a low bank of clouds is seen in the horizon, which you are surprised you did not observe before; a few seconds have passed, and the cloud has half filled the hemisphere, and there is no time to lose—it is a dust storm—and helter-skelter every one rushes to get into the house to escape being caught in it.
The electric fluid continues to stream down the wire unremittingly during the continuance of the storm, the sparks oftentimes upwards of an inch in length, and emitting a crackling sound; its intensity varying with the force of the storm, and as before said, more intense during the gusts.”
These dust-storms or whirlwinds when transferred to the ocean, would become whirlwinds and waterspouts,—being precisely the same phenomena—and a number of cases are recorded where they have been met with on the borders of typhoons, and of ships having performed various manœuvres to get clear of them.
On the subject of typhoons, a late writer asserts that the true theory of commencement or formation of cyclones in the Atlantic is “the intrusion of the S. E. trade-winds into the area of the N. E. trade-winds; and he tells us that this satisfies all the conditions of the cyclone problem, and is, therefore, the true solution of the origin of cyclones.”
I fail, however, to see that by this he accounts in any way for the progressive motion; and therefore see no reason to change my ideas with regard to the presence and influence of magnetism in these gales.
A few remarks on the barometer may be desirable in connection with this subject; and I will endeavour in as brief a manner as possible to explain its utility and action with reference to the subject of typhoons.
The first indications by the barometer of the presence, in its vicinity, of a typhoon is generally its oscillations or restless condition, which, though sometimes very small, not exceeding 01 of an inch, ought never to be disregarded.
A few cases are on record in which the oscillations at the mercury in the tube have reached 02, and of the same time the oscillation of the water barometer was .28 of an inch. These oscillations are caused by the disturbed condition of the atmosphere in front, and in the vicinity of the advancing gale. If the atmospheric fluid in which we live and breathe was visible to the eye, it would be seen on the approach of a Typhoon to move in great waves over the barometer, like the undulations of a troubled sea after a heavy gale of wind; and as the barometer measures exactly the weight of a perpendicular column of the air immediately above it, it in consequence rises and falls according as the atmospheric waves reach, pass over, and leave it.
The next thing worthy of notice is the fact that the barometer often rises just before the gale comes on; a fact which when properly understood will always put the seaman on his guard and give him timely warning, but a dangerous thing when not understood, as it tends to throw the seaman off his guard, and lull him to sleep, when he ought really to be wakeful and watching.
The cause of this phenomenon is evidently the air being banked up in front and by the pressure of the advancing gale; and can best be demonstrated by moving a large tub through a body of water, when it will be found that the water in front of the tub will be higher, and that the water behind the tub will be lower than that portion of the water which is not affected by the movement of the tub;—and this is just the case with the barometer, which as a rule is above in front of, and lower behind the gale than its average height, for the time being, in places not affected by the storm.
But we also find the barometer standing lowest at or near the centre, and this may be accounted for by the fact of a partial vacuum existing there from condensation of vapor, and the surrounding air rushing in to supply the vacancy, leaves room for neighbouring currents to expand and become lighter, a process which on this principle I suppose to be going on from the centre towards every part of the outer circumference; and the gradual fall of the barometer as a matter of course follows.
Now as the severity of a typhoon is measured by the velocity of the winds within the storm-disc—and we admit on the first principles that the greater the rapidity with which the currents revolve around the focus, the greater the condensation of vapour there, and hence the more perfect the vacuum at the centre—we shall have an explanation of the reasons why the barometer falls lower in a severe, than in a more moderate gale.
Last of all we have the barometer as a measurer of the distance from the centre, and although but little reliance ought to be placed on this, yet in some cases it might be of use in determining what to do with a ship caught in a typhoon.
By comparison of a great number of cases Mr. Peddington has constructed the following table, intended to guide the mariner in estimating the distance from the centre.
| Average fall of Barometer. | Distance from centre. | ||||||
| (Per hour.) | In miles. | Intime | |||||
| From. | To. | From. | To. | ||||
| 0.02 | 0.06 | 250 | 150 | 12 | hours. | ||
| 0.06 | 0.08 | 150 | 100 | 09 | hours.„ | ||
| 0.08 | 0.12 | 100 | 080 | 06 | hours.„ | ||
| 0.12 | 0.15 | 080 | 050 | 03 | hours.„ | ||
The above table gives the average of a great number of barometer readings observed during typhoons principally at shore stations, where the observations have been made accurately and regularly, and from which the distance corresponding to each reading has subsequently been ascertained; but nothing is shown here nearer than three hours before and after the passage of the centre; the averages here registered apply respectively to 12-9-6 and 3 hours from the centre as marked in the table. After a typhoon has been blowing nine hours, no average fall can well be stated, as sometimes the barometer continues to fall at the same rate, and at other times (in cyclones of what Mr. Peddington calls the first class) falls when nearer than three hours from the centre, at a rate in proportion as 1 to 4 when compared with that of the former three hours.
It we examined the barometer readings during the typhoon which passed over Yokohama in August 1872, we shall find that this rule nearly corresponds with what was observed by myself during that gale.
It will be remembered that the diameter of this typhoon was 105 miles; its semi-diameter 5212 miles; that the entire storm-disc was seven hours passing over the Idaho (or any other given point); and the time occupied by the semi-diameter in passing, 312 hours.
During the first hour the fall of the barometer was 0.14 of an inch, during the second hour 0.20, during the third hour 0.44, and during the remaining 30 minutes 0.21, showing, in this instance, a proportion of fall, by comparison of the third with the first hour in the ratio of 1 to 3; and the distance from the centre being 5212 miles when the fall of the barometer was 0.14 of an inch per hour, agrees nearly with Mr. Peddington’s estimate of the distance with a corresponding fall of the barometer, his distance being 50 miles, with an average fall of 0.15 per hour.
I infer from this that the distance of the centre in a typhoon from any part of it may be calculated approximately by this method, providing the observer is on shore, has a good barometer, and watches it closely.
The total fall of the barometer during the typhoons on record ranges from 1.00 inch to 2.70 inches; the latter in the case of H. E.I.C. S. “Duke of York” off Kedgeree in 1833, from 29.00 to 26.30 inches.
ARGYLESHIRE.
(See Diagram.)
The ship Argyleshire, here represented in a typhoon, was making a passage from Hongkong to Yokohama, and on the 11th of September was near the South end of Formosa, Betel Tobago bearing N.E., 23 miles. She was struck by a Typhoon with the wind at N.N.E. and the centre bearing E.S.E., and the captain believing the gale to be travelling to the Northward, supposed himself to be in the left hand semicircle, and continued on the port tack heading to the Eastward as near his course as possible, thinking all the time the centre would pass to the Northward of his ship ere he could approach sufficiently near to be in any danger. He evidently had an eye to business, and judging from the manner in which he handled his ship afterwards that he was conversant with the Law of Storms, I am of opinion that he desired to approach the centre, as near as would be consistent with safety, in order to take advantage of the Westerly winds which he knew he would find South of the centre, and by which he could lay his course for Yokohama and make good time. This would have been all right had the gale travelled North as he supposed, but the sequel in this case shows that seamen should never form hasty conclusions in cases where deliberation may be employed to advantage.
If the captain had hove the ship to at once, and awaited the first change of wind, he would have discovered that the gale did not—as he supposed—travel North, for in that case the shift would have been to the left of N.N.E. and not to the right as it actually occurred; but urged on I presume by zeal and ambition to make a quick passage, and do well for his owners, he kept on under a heavy press of canvas until spars and rigging threatened to give way, and the strain upon these momentarily increasing, he was compelled to heave to, which he did on the port tack, evidently still thinking he was in the left hand semicircle. But he was not long left in doubt as to his position for his falling barometer, the rapidly increasing force of the squalls, and the shortening of the intervals between them, the approach of darker and denser clouds, and the appearance of lightning in great quantities all told the story of the centre coming rearer the ship, and the idea evidently just occurred to the captain, that the gale was not travelling North as he supposed but coming to the Westward, and that he was heading nearly for the centre, as he at once wore ship and put her on the Starboard tack (the proper tack).
During the first 12 hours of the gale the ship sailed and drifted 118 miles S. 66° E. nearly E. S. E., (equal to 96 miles measured on the cord of the arc through which she passed) and towards the centre, until within 86 miles of the latter she was put on the starboard tack.
If this had been done at the beginning of the gale, she would not have approached the centre nearer than 150 miles; for the winds drawing to the Eastward, as the gale advanced to the Westward, she would have made no drift to the Southward, and she would have been in a safe position to receive the shifts—as each one would have been more aft—and the ship, coming up to the wind, would have been riding head on to the heaviest sea.
If we start with the “Argyleshire” from the beginning of the gale we may follow her on the broken curved line marked 1. 2. 3. &c., sailing E. by S. 63.5 miles, E. S. E. 58 E. 30 miles, S. E. 34 S. 26 miles, and after being hove to on the port tack, drifting S. by E. 6 miles. The wind gradually veering to the Eastward—or to the right (unmistakable evidence of being in the right hand semi-circle) and at the last named point it was N.E. 12 N.
It will be remembered that while the ship was sailing to the S’d and E’d, the gale was advancing to the S’d and W’d at the rate of 8.4 miles per hour, and during 12 hours 100.8 miles, while the ship, in the same time having sailed 118 miles S. 66° E. and, as shown, above 96 miles on the cord of the arc of the Storm-circle through which she passed. It follows that at the end of 12 hours she had passed through 196 miles of the Storm-circle, on the cord of that arc, and nearly in direct opposition to the course of the gale.
Dropping a perpendicular from this point on the cord, it will cut the line A. C. in the angle “A,” and point out the actual distance over this line 216.7 Miles, and her distance from the centre at the time of wearing ship 86 miles.
The numbers 1. 2. 3. &c. on the line A. C. point out the particular part of the gale that passed over the ship in her real position, indicated by corresponding numbers on the broken curved line, and consequently her actual track through nearly one half of the Storm-circle, the point at the angle “A,” in the Storm-circle corresponding to the point “A” on the ship’s track. On the starboard tack, the ship during an interval of 30.26 hours—drifted and sailed W. 58 N. 13 Miles, N.N.W. 12 W. 17 miles, N. 78 E. 18 miles, N. by E. 12 E. 12.6 miles, N. E. 12 E. 27 miles, N.E. by E. 18 E. 28.8 miles—making good a course and distance equal to N. 23° E. 83.5 miles, which, when measured on the cord is equal to 45 miles. The letters A. B. C. &c., on the line A. G. correspond to the same letters on the broken curve, marking the ship’s track on the starboard tack, and point out the particular part of the storm that passed over the ship in her place on the curve, as indicated by such corresponding letter. The line A.G. also shows the ship's track through the last half of the storm-circle, and measures 314 miles corresponding toa distance on the cord equal to 300 miles. The diameter of the storm-disc is computed at 588 miles, and its rate of travelling 8.4 miles per hour.
It is here made evident that the “Argyleshire” passed through a distance in the storm-circle equal to 530.7 miles, contained within an angle of 115°, the cord of which runs nearly parallel with the course of the gale and measures 496 miles. The “Argyleshire,” during the first half of the gale experienced the winds, as follows: N.N.E., N.N.E. 18 E., N.N.E. 14 E., N.N.E. 12 E., N.N.E. 34 E., when the ship was hove to on the port tack, and the wind soon began to veer more rapidly, and in a short time veered to N.E. 12 N. The reason why the wind veered so slowly previous to heaving to was because she was running nearly direct for the centre, and therefore chaning the bearing of it but slightly; and this circumstance ought to have attracted the attention of the captain to his mistake in supposing the gale to travel to the Northward; for in that case, running as he was to the S’d and E’d, he should have changed the wind to the left—that is—from N.N.E. to N. by E. N. N. by W. N. N. W. &c. &c. &c. until eventually, when he should have reached the Southern portion of the Storm-disc, he would have had the wind from the W’d, and gradually changing to the S’d and W’d.
FRANCIS HENTY.
The Francis Henty, of Melbourne, Captain William Thomas Quayle, left Saddles on the 4th of October, 1872, bound for Yokohama, and stood across the Tung Hai, or Eastern Sea, with northerly gale for Van Dieman’s Strait. The wind, however, hauled to N. E., and headed the vessel off, so that she could not fetch or lie up to her course, and on the morning of the 7th, running down on a course for Colnett Straits, she passed close to Ingersoll Rocks. Strong indications of typhoon to the S. E., and thick weather prevented the captain passing through the Straits. Low barometer, heavy cross swell, occasional flashes of lightning, and a general threatening appearance of the weather, determined the captain to keep on the western side of the chain of islands, and await the result of the coming gale. On the morning of the 8th barometer rose 0.2, from 29.30 to 29.50, a circumstance that caused the captain to think he was all clear of the typhoon, and so hauled up on the wind and passed through what he calls Monturose Pass, between the islands of Tokara and Tokasima, standing E. S. E., between Cape Monturose and Macedonian Rocks, to a point in latitude 28 deg. 34 min. N. and long. 129 deg. 54 E., the ship’s position when the typhoon commenced; but the wind having changed to E. S. E., Captain Quayle stood to the N. and E’d., and while doing so, the barometer rose to 29.70. This calmed the mind of the captain, who, up to this time, had been exceedingly anxious, in consequence of the proximity of land to leeward. He believed that he was all clear of the typhoon, and that it would pass on his quarter (to the N’d. and W’d.), but he was not destined long to rejoice in this sweet illusion, for he quickly discovered that he had misinterpreted the message of his faithful barometer, which soon after began to fall rapidly, and the wind increasing in due proportion, gave notice that the dreaded gale had caught him, and left him no way by which to escape without the risk of placing his ship in imminent danger, and being wrecked on one of the numerous islands composing the Loo-Choo and Linschoten groups, should he attempt to pass through, being at this time unable to see anything but dark and frowning clouds which seemed to rest upon the surface of the ocean. In this dilemma he resorted to the only thing left for him to do—hove his ship to on the starboard tack. The wind at this time blew with such fury, that canvass, however small, exposed to its force, was instantly blown into ribbons and torn from the ropes. Gust after gust followed with increased violence, and the wind remaining nearly stationary, and the barometer falling rapidly, told the dreadful story that the centre was approaching.
Lightning descending in vertical columns (of what Capt. Quayle describes as vivid green) added horror to the scene; and it is only necessary to hear Mrs. Quayle (who, with her children, was on board at the time) tell the story of her troubles and anxiety during that fearful night, in order to appreciate more fully the necessity for avoiding the centre of these violent gales; a thing which may be generally accomplished with safety, if the mariner is conversant with the Law of Storms.
There are a few exeptional cases, in which there is no escape; and the “Francis Henty” furnishes an instance. She was practically land-locked to leeward, the land being shut out from sight by a black cloud in which the “Francis Henty” herself was enveloped, and uncertain of her position, to attempt to run through one of the narrow passages between the Islands would have involved the ship and crew in great danger by grounding on some of the Islands or rocks in their vicinity. So of two evils the captain chose the least; and preparing his ship by passing extra gaskets on the sails, lashing the spars and other things liable to get adrift, making hatches and sky lights more secure, getting relieving and other tackles ready for instant use &c., &c., he adopted the proper course by heaving-to on the starboard tack, being in the right hand semicircle, and awaited the passing of the centre. This, in due time, took place. When near the centre, the ship was thrown on her beam ends with the yard-arms in the water and was so kept, by the fury of the wind pressing her down, until the centre reached her, when she righted in the calm that followed. She was, however, not more safe there, than when exposed to the blast, for the heavy and irregular sea there threatened every moment to swamp the ship.
During a light breeze, while the centre was passing, the Captain wore ship, and put her on the port tack to prevent (as he says) the ship from foundering against the lee sea, when the shift should come from the N.W.; and by this manœuvre he evidently saved his ship: for although somewhat out of order according to the Law of Storms—as he was in the right hand semicircle still—yet subsequent events proved that he was right. The events to which I refer are the incurving of the winds, evidently caused by coming in contact with the chain of Islands composing the Loochoo and Linschoten groups, and as the winds here represented are those that were felt at the ship, it will be noticed that as the ship drifted to the E’d, the winds became more Southerly; and the inference drawn from this fact is that the Island of Oho Sima (which is high land) arrested the course of the wind, and diverted it to a more Northerly direction, so much so, that, when the ship bore N.N.E. 12 E. 23 miles from the Northern point of Oho Sima, the wind at the N. W. by W. Typhoon point, was actually S. W. drawing up between the Islands of Oho Sima and Tokasima (being diverted seven points); and had the ship been on the starboard tack then, she would have been taken aback by every shift, got sternway, and probably foundered.
If this be true of Oho Sima, it is also true of any other similar land, and an important lesson is taught by Captain Quayle’s experience, viz:—when struck by a typhoon in the vicinity of land, remember that the contact of the wind with land diverts its course in proportion to the angle of contact, and, therefore, make proper allowance for such change in locating the centre, or in determining the tack on which to heave to.
This Typhoon may be cited as a remarkable instance of the in-curving of the winds by contact with land—which is here clearly established—but I doubt very much if any considerable out-curving of the wind could ever take place, even should the angle of contact with the land be such as to give it a tendency in that direction, because of the atmospheric pressure being so much greater on the outside than on the inside.
By reference to the Diagram, we find the Francis Henty entering the typhoon in N.E. by E. quarter, or having the wind S.E. by S. and follow her through the first half of the storm-disc to the centre, the wind having changed but one point to S.E. This change of wind is the effect of having changed the bearing of a centre, first by running to the Northward and Eastward on a course inclining towards the track of the typhoon; and secondly, by heaving to and drifting to the Northward and Westward. Run and Drift together during 1112 hours, making good a course and distance N. 7° 55′ E. 68.5 miles—on the line marked D.R.1., and following her from the centre out, we find that she is drifting to the Eastward, making good a course and distance S. 83° 24′ E. 44.37 miles, on the line marked D.R. 2: but at the end of the Typhoon, the Captain discovered the Macedonian Rocks, 7 miles to leeward, bearing S.S.W. 34 W. and 71 miles S. 52° W. of the point where his reckoning placed him. This indicates a strong current having affected the drift of the ship during the gale, at the rate of 3.24 miles per hour, S. 52° W. or S.W. 58 W. Applying this current to the course, through the first half of the storm-disc, we shall find that the ship travelled, through the storm-disc, on the straight line marked 1, 2, 3, 4, 5 and 6., and that her track over the ground was on the broken line having the corresponding marks; also that her course through the last half of the storm-disk, lies on the straight line marked a, b, c, d, and e, and that her actual drift over the ground is indicated by the curved line similarly marked.
Diameter of the storm-disc, 360 miles, and rate of travelling 16 miles per hour, N.E. Diameter computed from the time required for the Francis Henty to pass through the storm-disc, and the rate of travelling obtained by having the bearing and distance of the centre from two known points, at different times, and the elapsed time during the interval.
I have confined myself so far to data and figures, absolutely necessary for the explanation of my diagrams, and will not tire you with a recital of the computations by which I have arrived at the above conclusions, and upon which I base my assertions; but should any person here present desire to investigate the subject more fully, I shall be most happy to show the computations, and render such explanation as may be desired to clear up any little point imperfectly understood.
CAPTAIN QUAYLE’S LETTER.
“Left Saddles at 1 a.m. on the 4th October; with fresh northerly gale and high sea, wind veering to N.E., found it impossible to pass through the straits of Van Dieman. On the 7th passed close to Ingersoll Rocks, but weather so bad did not go through the claws, having indications of a typhoon to the south’d and east’d. On the 8th October glass rose 2.10, thought I was clear of typhoon; wind E. S. E., thought it would pass on my quarter; went through the Monturose pass with strong gale; stood to the north’d for eight hours, then tacked to the N. E., barometer 29.50. As I stood to the north glass rose to 29.70, thought I was all clear. Lee shore distant 30 miles made me very anxious. At 11 p.m. glass began to full rapidly, and wind came out steady at S. E. by S., the typhoon having evidently struck the Loo Choo Islands and recurved coming right down on the ship. Stood north as long as possible under heavy press of sail. At midnight on the 8th barometer 28.65, blowing terrific gusts, sea resembling church steeples. At 3 a.m. 9th October, barometer 28.21, took in main top-sail, and put ship on starboard tack, being in the right hand semicircle; at 4.30 the scene was fearful; gust upon gust, and sea running high but not breaking owing to the wind. At 6 a.m. barometer 27.50, men lashed on deck, nothing visible of ship but a portion of her weather deck, on her beam-ends, yard-arms in the water. At 7 a.m. barometer 27.29, when suddenly it lulled and the centre passed. Drift, up to this time, 512 knots per hour, N.W., was expecting every moment to hear the ship crushing on the reefs. Wore ship during a little gust in the centre, and put her on the port tack to prevent her from foundering against the lee sea when the wind should shift. The second mate washed overboard while wearing, but managed to crawl on board again. The bulwarks all washed away. In the course of 30 minutes the shift came, N.W., terrific blowing, harder than before, throwing ship down, washed away cabin and all my effects, nearly wife and children. At 8 a.m. 9th gave up hopes of ship and crew; compressed air below blowing up hatches and scuttles in the cabin, barometer at this time 27.19, clouds resting on the water, and the scene was fearful. The lightning falling in a vertical column of vivid green; the wind constantly veered to the south’d and west’d, and at midnight the wind was S. W., blowing a fresh gale; set storm canvass to steady the ship. Oct. 10th a.m., daylight, gone down to moderate gale, but high sea. At noon the reefs in sight were seven miles to leeward. The whirl of the storm kept the ship off.”
CHART OF BAROMETER CURVES.
(See Diagram.)
The Chart shows the barometer curves as indicated by the barometers of the respective ships herein named: the “Argyleshire”, Sept. 1872, the “Francis Henty”, October 1872, and the “Idaho”, August 1872. An inspection of these Diagrams affords a comparison of the gales as to size and severity, supposing the fall of the barometer to be a measure of the latter. The Chart is constructed on a scale of 20 nautical miles to an inch, or say 11,500,000 part of the actual size (nearly).
Hence, the length of the Diagrams shows the diameter and relative diameters, and the form of the barometric curves the severity and relative severities of the gales which they are made to represent: Thus it would appear that the “Argyleshire’s” Typhoon, although larger than either of the other two, was not as severe; as at a distance of 204 miles from the circumference, the fall of the barometer was only 0.93 inch; but it will also be noticed that the “Argyleshire” did not pass nearer to to the centre than 86 miles, and the lowest barometer reading was at 90 miles from the axis of the centre, and 45 miles from the actual boundary line of the calm space; it is, therefore, probable that her barometer might have fallen another inch before reaching the central axis, but this, of course, I have no means of knowing, except by comparison with the fall of the barometer during the Yokohama Typhoon, August 1872, in which the barometer fell 1.01 inches from the beginning to the axis of the centre, a distance of 5212 miles.
Next, we notice the Francis Henty’s Typhoon, and observe the barometer falling rapidly, showing a total depression of 2.51 inches. This was an exceedingly severe gale, and the fall of barometer went far below the average, the greatest fall recorded heretofore being 2.8 inches, and the average of excessive falls of the barometer recorded does not exceed 2 inches. 1.96 inches, I think, are the figures.
The diameter of this gale was 360 miles, and the calm space in the centre 60 miles.
Next, and last; we have the Yokohama Typhoon, which occurred on August 25th 1872.
The barometer, during this gale, was observed by myself every 15 minutes from the beginning to the end, and I have, therefore, no hesitation in saying that this curve is accurate and complete. The total fall of the barometer was 1.01 inches. The diameter was 105 miles, and the calm space in the centre, 15 miles.
In connection with the fall of the barometer, it will perhaps be proper to remark on Captain Quayle’s idea of the compressed air below blowing up the hatches and scuttles in the cabin, as stated in his letter. That this circumstance should not be attributed to the compression of the air, but just the opposite, to expansion of the air, may be explained in this way: When the ship entered the storm circle, with a high barometer, a quantity of air of the same density as the surrounding atmosphere was confined below; and this being unable to escape as the barometer fell, owing to the tightness of the hatches, eventually, when the barometer fell very low, and consequently the outside pressure was partly removed, expanded and forced up the hatches, or such portions of the deck confining it as happened to be weakest. This would not have occurred a second time, as an equilibrium of forces was soon established, and the pressure equalized on both sides.
There are two essential rules of vast importance to the seaman to be remembered in connection with circular gales, and which will always be a sure guide.
The first of these is: That the wind in the right hand semicircle always changes to the right of the point from which it blows, and the second: That the wind in the left hand semicircle always changes to the left of the point from which it blows.
This is true in both hemispheres.
Two other rules should be remembered as equally important. The first is: That in the Northern Hemisphere the bearing of the centre of the gale is always eight points to the right of the direction of the wind—as when the wind is N. the centre bears E. The second is: That in the Southern Hemisphere the bearing of the centre is always eight points to the left of the direction of the wind, as when the wind is N., the centre bears W.
Two other rules of equal importance should be remembered. The first is: In the right hand semicircle heave-to on the starboard tack. The second is: In the left hand semicircle heave to on the port tack—in both hemispheres.
It will then be seen that a ship laying-to in the right hand semicircle in the Northern Hemisphere, will be on the starboard tack, and heading off from the centre; and in the left hand semicircle, will be on the port tack, and with her head towards the centre. Also: In the Southern Hemisphere, a ship laying to in the right hand semicircle, will be on the starboard tack, but heading towards the centre; and when in the left hand semicircle will be in the port tack, but heading off from the centre.
Difference of Longitude 449
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Elapsed time between two known positions of the Centre 55 hours |  |
hence 460.855=8.4 miles Rate per nearly. |
| Whole distance traversed by the Centre during that interval 460.8 miles | 
|
| Port tack | S. | 66° E. | = | 118 | miles | |
=N. 78 E. 141 miles = to the distance made good on the Cord connecting the two ends of the arc of the storm. |
| Star. tack | N. | 23° E. | = | 083.5 | miles„ |
|
- Disk through which the “Argyleshire” passed.
Length of Cord.
| Port Tack. |  |
|
0096. | Miles | ||
 |
|
0100.8 | Miles„ | |||
|
0196.8 | Miles. | ||||
| Starboard Tack |
 |
|
0186.564 | Miles.„ | ||
 |
|
0045.000 | Miles.„ | |||
 |
|
0067.62 | Miles.„ | |||
 |
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0495.984 | Miles.„ |
Diameter of Storm Disk.
Upon a knowledge of these simple and few rules depends the safety of a ship; and these constitute all that is necessary to locate the position of a ship with regard to the bearing and movement of the centre, as the direction of the wind gives you at once the hearing of the centre, and several consecutive bearings of the centre will give you, approximately, its movement; while the first change of wind will tell you whether you are in the right or left hand semicircle. Thus located in the storm circle the rest depends on the judgment of the commander.
To demonstrate these rules would require a number of diagrams and more time than, perhaps, the greater portion of this audience would be willing to give to a subject of that kind, which would necessarily be dry, and of little interest to any; but such few as may happen to be connected with the sea, or are otherwise desirous of investigating the matter more fully, I would refer to the works of Reddington, Reid, Redfield, Dove and others for a full and complete discussion of the matter. Yet to the practical seaman, who wants a great deal of substantial information in a concentrated form, I should recommend some of the smaller works written on the subject, all of which are more or less adapted to the wants of the practical sailor, A small work of that kind, entitled “Weather Guides,” is one of a number of other useful books written by Rear-Admiral T. A. Jenkins, U. S. N., while he was doing duty as Chief of the Bureau of Navigation, in Washington, D. C., and is an excellent book for reference and consultation when you wish to get an idea quickly and do not have time to hunt it up in the larger works.