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• Observations on the Dip. 1818. Latitude. Longi- N'of Observer.
Remarks. tude. Obs.
April 135i 31 N. o ośw. 16 Capt. Kater 78 34 36 s Regent's Park,
London. 30 60 091 1 12 14 Capt. Sabine 74 22 48 Brassa Island, May 160 093 1 12 12 Lieut. Parry 74 20 10 S Shetland. June 968 22 53 50 12 Capt. Sabine *83 08 07 On ice.
1970 26 54 52 14 Capt. Sabine *82 48 47 Hare Island. July 874 04
(Baffin's) three 57 52 10 Capt. Sabine 84 09 15
Islands, 25 75 05 60 03 10 Lieut. Parry 84 24 57
475 59 64 47 10 Capt. Sabine 84 52 06 On ice.
25 76 08 78 29 16 Capt. Sabine 85 59 31 On ice. Sept. 1170 35 66 55 10 Capt. Sabine 84 39 21 On ice. Nov. 360 093 1 12
Lieut. Parry 74 21 06 Brassa Island, 360 09
1 12 14 Capt. Sabine 74 21 47 155 Shetland. 1819. March 151 31 O 08 16 Capt. Sabine 70 33 16
s Regent's Park,
With respect to the variation of the horizontal needle, or compass, Captain S. has supplied many excellent observations, from which we are enabled to draw at least one certain conclusion, viz. that the north magnetic pole of the earth (if such a pole there be) has not hitherto been rightly assumed. According to M. Biot, this pole ought to be found in lat. 78°N. and long. 25o W.; whereas it appears from the table given by the present author, that in lat. 75° 59' N. and longitude 64° 32' W., the needle, instead of standing north and south, stood directly west and east; that is, the north end of the needle pointed due west; consequently, the terrestrial magnetic pole must lie westward of this place; and, therefore, in a much higher western longitude than it has been hitherto supposed to be. In latitude 70° 8' N. and longitude 78°21' W., the variation was 110° 58% W.; that is, the north end of the needle had passed the west point, and was approaching towards the south: from which, we think, a conclusion may be drawn that, instead of the north terrestrial magnetic pole being situated in north latitude 78°, it cannot exceed the parallel of 75°; and its longitude is in all probability not less than 80° W., if, indeed, it does not far exceed this amount.
We come next to the experiments relative to the magnetic intensity, which appear to have been made with every precaution necessary to ensure a proper degree of accuracy; with one important exception, namely, the temperature of the at
mosphere mosphere at the time of observation. The following is an abstract of the several results:
Abstract of the Times in which 100 Vibrations were performed.
• The 100th vibration never exceeded an arc of 3.' By examining the numbers in this table, it appears that a certain degree of acceleration takes place as the latitude and dip increase : but is this to be attributed to a nearer approximation to the terrestrial pole, or is it due merely to temperature? M. de Humboldt found a similar acceleration at Paris, as compared with the rate of vibration in Peru: but here again the same question occurs; How far was this acceleration due to climate? This is an inquiry which does not appear to have suggested itself to the minds of these philosophers; although strong reasons appear to indicate that such was the principal cause of the change in the number of vibrations in all the cases. Mr. Canton, in his attempt to account for the diurnal variation of the needle, proves by the most incontestable experiments that the intensity of magnets, whether natural or artificial, decreases while the magnet is heating, and increases again as it cools; consequently, the intensity of action will be greater at Paris than in Peru, and greater in Baffin's Bay than in London, although the distance from the magnetic pole were the same in every case.
Hence we are bound to conclude that, the temperature being omitted, the experiments before us are of little or no value.
The azimuth-observations were made principally with Kater's compass; with regard to which, Captain Sabine observes :
When due consideration is given to the greatly diminished power, with which the earth's magnetism acts on the horizontal direction of the needle, when the dip becomes so considerable as it was found in Davis's Straits and Baffin's Bay, namely, from 830 to 86°, the satisfactory results which bave been obtained, even
"under such extreme circumstances with Captain Kater's compasses, afford the best testimony of their excellence and of the precision which may be expected from them in the ordinary course of observation.
• It may also be remarked, that a difference in the result of azimuths observed at different hours of the day may not be altoge : ther an error of observation, since it is probable that as the directire power of magnetism diminished, the causes which produce the hourly change in the variation itself may act with increased effect.
• Should the amount of this change be considerably augmented in high magnetic latitudes, careful observations on the direction of the needle at different hours of the day, on all convenient occasions, might be serviceable towards a more certain knowledge of its causes, than has been hitherto obtained from observations made where the effects are so inconsiderable.
· The influence of the ship's iron on their compasses increasing, as the directive power of magnetism diminished, produced irregularities that rendered observations on board sluip of little or no value towards a knowledge of the true variation ; a few azimuths which were observed in the Isabella have been selected for the purpose of exemplifying this remark. They will also show, how essential it is to navigation in high latitudes, that the nature of the errors which the ship’s attraction produces in her compasses should be understood.'
We agree entirely with Captain Sabine, that it is of the highest importance in navigation to be able, not only in high latitudes but in all latitudes, to ascertain the quantity of local attraction as produced by the ship’s iron; and we think that the subject is well worth the attention of British mathematicians.
Since the above remarks were written, Mr. Barlow of Woolwich has published a work entirely devoted to this inquiry *, in which he proposes an easy experimental method of determining the amount of deviation in all parts of the world. We hope to be able to undertake the examination of this volume in a future number of our Review.
[To be continued.]
ART. IX. The Banquet ; in Three Cantos. Svo. pp. 144. 55. 60,
Boards. Baldwin and Co. 1819. ART. X. The Dessert, a Poem; to which is added the Tea. By
the Author of “ The Banquet." Svo. pp. 109. 58. 6d. Boards.
Baldwin and Co. ART. XI. The Vestriad, a Poem. By Hans Busk, Esq. Author
of "The Banquet," “ The Dessert," &c. 8vo. pp. 380. Boards, Colburn. E very day more clearly manifests the uncertainty of literary
reputation. Here is an author of very gentlemanly attainments; and, doubtless, with much to recommend him to
* “Essay on Magnetic Attractions, particularly as respects the Deviation of the Needle on Ship-board,” &c. Rev. FEB. 1820.
his predisposed admirers : - but that the English public, of all other publics, should be pleased with this feeble kind of wit is an occurrence that, with many similar events, entirely baffles all previous conjecture as to the probable popularity of a work. Our old, solid, and substantial readers, who, after all, are generally the best judges of humour as well as of philosophy,—will curl their whiskers, we think, with rather a sarcastic smile at the subjoined specimen of the ludicrous, from the Banquet.' Vatel
, the man-cook of the Prince de Condé, is the subject of the passage. The story is well known, and charmingly related, as all stories are, in the Letters of Madame de Sevigné. A translation of the original tale is also printed in the present author's notes, which serves still more sufficiently to shew the languor of his own representation :
O" Wretch that I am !" in agony he cried,
• The Prince was soon acquainted with the whole,
Forget the roast, far better to have none,
6 " My Prince ! this goodness how can I repay ?
Not long endures the respite and relief :
No sturgeon, turbot, and no salmon jole,
scatter'd round the frothy words in air.
But grief's black tide it is o’erwhelms his soul.'
There is an indistinctness (not to say an unmeaningness) in the productions of this gentleman, which forms an insuperable bar to his lasting popularity. No class of readers can long be satisfied with what they do not understand; however fashion or affectation may for a time enlist them on the side of the obscure or the inaccurate writer. Where we do discover the object of Mr. Busk, it is too generally pursued without any plan or order; and he skips about from one part of his thesis to another, with agility equalled only by his prolix and tedious feebleness on other occasions. • The Dessert is dedicated to Mr. Walter Scott; who, it seems, in an easy and unguarded moment, had been betrayed into certain panegyrical expressions relating to the Banquet.' These, we think, must long since have been repented: but, if not, we shall admire that firmness of friendship which can endure such repeated shocks as the Dessert, the Tea, and the Vestriad. The dedication is followed by a preface, which to our minds presents a combination of bad puns with a complete nothingness of remark, not usually exhibited within the same space of letterpress. We are then introduced to the Desserť itself; a