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I have next delineated the whole of the tracks with the winds at noon upon the general Chart, and from these are deduced the centres, which last I have marked by a single circle or two for each day, and from the centres I estimate the course of the hurricane. To render the whole more distinct, three diagrams are also given, to half scale, upon which I have a few remarks to make.
In considering these diagrams and tables, the reader will be struck with some few anomalies; that is, he will observe that the arrows do not always show the wind as blowing in exact circles, and that in one or two instances, they are altogether different from the others, though not absolutely contradictory.
I take these few discrepancies mostly to arise from some one of the following causes :—
I. The carelessness of many in noting the direction of the wind, or the not noting it at the time.
II. Their erroneous estimation of its direction when looking at a weather-cock or dog-vane, and, if a ship is going fast, the not allowing for the effect of her motion upon it.*
III. On shore, local circumstances, such as houses, hills, rivers, and the like, which may often produce differences.
IV. At sea the vicinity of the land, ranges of mountains, &c. which when the gale or hurricane strikes them, occasion a re-action altering the direction of the wind.
V. As it has been necessary to fix upon one instant of time at which to compare the wind and weather experienced by different vessels, noon has of course been chosen ; but when the winds are varying, it may occur that the one marked about noon is a little more unfavourable to the appearance of the diagram than that which perhaps was the predominant one throughout the day; as, however, it would have appeared like accommodating the facts to the hypothesis, I have preferred allowing them to stand as marked, taking a mean point where the limits of the variation of the wind are expressed, such as SE. when the words "between South and East," are used.
VI. The positions of the vessels are rarely accurately ascertained in a severe gale.
Let us consider these causes separately. The careless habits of seamen are well known, and that these should extend to what is apparently the unimportant matter of noting the exact direction of the wind is not surprising, and is well known to every intelligent man, who has commanded a vessel. In severe weather too when a vessel
*The eddy wind from the mizen staysail will sometimes in a small ship affect the dog-vane.
is lying with her yard arms in the water, boats and booms washing away, and sails blowing from the yards, those on whom the responsibility rests have far other matters to engage their attention than the exact direction of the wind; and in many vessels, where perhaps the captain and chief mate are the only persons who can take charge of the deck in such weather, the log is rarely marked till the gale ceases, and it is written up perhaps at a still later period. "You must not look for very great exactness in my log, Sir, for to tell the truth, every word of it was written from memory after the gale was over; myself and the mate had something else besides writing to do while the gale lasted," was literally said to me by one commander; and no doubt this is necessarily true of many, as those who know the severe fatigue of body, and excessive anxiety of mind which the masters of small vessels must undergo in bad weather will readily allow.*
2nd. That when the vessel is going fast through the water the dogvane shews the wind to be further a head than it really is, is well known to all; when close hauled on a wind, as the vessel lies about six points from it, there is no mistake of any consequence to be made, but with the wind abeam or a point or two abaft it, many officers do not, if they know it, make due allowance for the ship's motion. If the wind appears to be abeam it is put down so, though it is perhaps half a point or more abaft it. The experienced and attentive do not of course fall into these errors; but how many are there who unite both experience and attention? Looking at a weather-cock on shore, or merely estimating the direction of the wind, is more liable to be inaccurate; even to the extent of a point or two.
3rd. Local circumstances, such as I have alluded to, require no remark, particularly when an observer is living in a large town, or has not a very exact idea of his meridian; which but few have.
4th. This cause will be more particularly alluded to in Part II of this memoir; at present with reference to one diagram the anomalies about Juggernaut, or as the ships approach the shore, seem quite probably referable to the repulsion of part of the vortex from the high land behind Cuttack; or to the great current of the regular monsoon gale, blowing up along the Coromandel hills. See Part II.
5th. The fifth cause explains itself, as stated.
*Note. While this is going to the press I meet in the Nautical Magazine for March 1839, in a valuable paper on a hurricane, "Yesterday I did not put down the latitude and longitude. I calculated it roughly in my own mind, and satisfied myself the Barque was driving clear of the shoals. I was too much occupied, both mentally and corporeally, to enter into minute calculations."-Extract from a letter signed * Mexicano,' giving an account of a gale off the coast of Mexico.—Nautical Magazine, March, 1839.
6th. The sixth requires none to seamen, but the unprofessional reader should be told, that, not only from the motions of the vessel and the haziness of the horizon, observations during stormy weather are entitled to but little confidence, but moreover they are but very seldom obtained, the celestial bodies being rarely visible; thus the latitude and longitude of the vessel is in truth but little better than guessed at if she is lying to, because neither the direction nor the rate of her drift can be well measured by the log, or accurately known by the compass; as it may be when scudding. Hence it must be borne in mind that, though the wind may be rightly noted, the ship's position may be to a certain extent erroneously laid down, and in some instances upon the diagram, if the vessel be supposed to have been little further to the East or West, or to the North or South, the apparent difference will disappear.
The Sarah in the diagram of the 4th is an instance. By the direction of the wind she should be further to the Eastward; but I estimated her to be where I have placed her. At 2 P. M. also, as will be seen by her log, the wind veered to the Southward with her; the centre of the vortex having passed her at no great distance; the weather moderating till 4 P. M. when it again came on to blow a hard gale.
It may be observed to, and this is important, that while probably, and frequently no doubt from the causes just enumerated, there are discrepancies in the winds as laid down, these rarely, or never, amount to contradictions of the theory; which defines a hurricane to be a severe gale blowing and veering round in a circular direction, while it is also moving onwards. I should note also that in more than one instance I have found no wind marked exactly at noon, but one at 10 a. M. or 2 P. M. With this explanation of the diagrams and charts the unprofessional reader will be better able to make allowance for the differences he may meet with; and all will observe how well the blank which occurs on the eastern side of them will be filled up by the logs of the homeward bound vessels. The description of the Map No. II. belongs to Part II. to which it has reference.
The slow rate of progress of our hurricane will not fail to be remarked. I think it probable this is owing to the vortices being pent up as it were between the course of the gale and the Coromandel Hills. I have further adverted to this also in Part II.
A few more remarks on the Logs and Charts may not be without interest, both to the unprofessional reader, and to the seaman who may not at once perceive how they bear upon the theory of the circular motion of storms; and that this is from East to West by the North, or contrary to the hands of a watch, on the North side of the equator.
Let us begin with the H. C. S. Amherst, which we find very properly stood out to sea from the tail of the Eastern sea reefs. Had her Commander not been acquainted with the Sand Heads, she might have been placed in great danger by standing in, as she then must have anchored in a most perilous position. This was probably the fate of the unfortunate Protector, in which 135 soldiers were lost beside the crew and the passengers, in the gale of October, 1838.*
The Pilot vessels, whose business moreover it was to keep as near to their station as they could with safety, were well managed of course ; as were also the Sarah and I believe the John Hepburne, a Schooner from Rangoon; though I have not been able to procure this last vessel's log.
On the South-side of the hurricane, however, many of the vessels seem running into it, and this some of them certainly did. The Mary Somerville was fortunately prevented from doing so, by the accident to her foretop-mast, obliging her to lie too, but the Ann Lockerby, Justina, and Eden seem to have run right towards it.
The Susan's track shows a course made much too far to the Westward for the winds laid down; this is only to be accounted for by the erroneous estimate of her position, and the Westerly current which is adverted to in the logs of the Nine and Jane.
The barometrical observations are for the most part so few and scattered that I have been unable to trace any connected series of them worth adverting to. As usual the barometer has clearly enough announced the approach or vicinity of bad weather, and the Simpiesometer still earlier. I have before stated that I was unable to obtain more than one single notice of the heights of the vessels' barometers in the port of Calcutta! and thus we are left to doubt as to the correctness of even those instruments of which we have the registered observations. Thus the 'Nine's' barometer indicated a very remarkable depression on the 1st, 2nd, and 3rd June, but was it a correct one? The low rate of pay on board our merchant ships makes it a heavy tax upon a commander to provide himself with instruments from the best makers. I cannot quit this part of the subject, however, without citing the highly creditable barometrical observations of Mr. Hudson, commanding the Honorable Company's Floating Light Vessel "Hope," marked in the tables as the Upper Light Vessel. I have only there quoted his barometer for noon; the following is the register annexed to his log, and brief notes of the weather from it
* The remarks on the appearance of the Arracan mountains on the 29th, and the clear sky and peculiar sensibility to noise on board at the approach of the gale, are very interesting the two last may have been electrical phænomena, and the first will remind the seaman of "the Devil's table cloth," at the approach of a South-easter in Table Bay.