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Let me for once describe her once,-for she
TO THOMAS CAMPBELL, ESQ.
An Expostulatory Epistlc occasioned by the following passage in his Specimens of English
« Stevens celebrated hard drinking, because it was the fashion and his songs are now seldom vociferated, because that fashion is gone by.” Specimens, Vol. VI. p. 437.
Sir, in your last work you the logic display
* Four logicians. The first as honest a fellow as ever filled a pipe ; the other three were mode and figure men.
of It is not worth while to print after the etymon of this word ; in Ireland it signifies a sluttish awkward woman ; it is synonymous with the short word for female dog.
Come over among us, sweet bard, and I swear,
For my punch is just out and I'm ttir'd, Mr Campbell.
• Reddish cloth, used by B. Jonson, Beaumont, and Fletcher, Sir W. Davenant, &c.
+ Tired, according to Cobbett in one of his "years residences in America," is a quaker word to express drunk. How true this is I know not; but I supplicate the gentle reader to take it here in its more usual sense.
I i.e. Post ten tumblers.
ABSTRACT OF METEOROLOGICAL OBSERVATIONS FOR 1819.
MR EDITOR, The following abstract of my meteorological observations for 1819 will be found I hope, not altogether uninteresting. I am aware, indeed, that of its intrinsic value, your readers and I may probably entertain very different opinions. To some it may appear a very dry morsel amidst the more exquisite and delicious viands which your monthly bill of fare contains, while my own eye will be running over the dense columns of figures with all the pride of a successful theorist, contemplating the experimental proofs of his favourite speculations. But whatever importance may attach to the subject itself, I can assure your readers that they may depend on the accuracy of the facts stated below.
The titles of the different columns, under the heads Thermometer and Barometer, are abundantly obvious. Those under the Hygrometer may, perhaps, require some explanation, particularly the three results deduced from Mr Anderson's principles of hygrometry: The first of these is the pojut of deposition, or that temperature at which the air, if cooled down, would begin to deposit its humidity. The second is the absolute quantity of moisture contained in a hundred cubic inches of air, expressed in decimals of a grain, Troy. And the third is the relative humidity of the atmosphere, supposing absolute dryness to be denoted by 0, and saturated by 100; or, in other words, the quantity of moisture expressed in hundredths of what would produce complete saturation. For a farther explanation, I refer to your twenty-second Number, page 472.
Latitude 56° 25', Elevation 185 feet.
42.5 33.3 38.2 36.8 37.9 37.5 9.2 41.144 29.422 44 29.390 44 29.406.191.197.388 41.7 31.9 36.9 35.6 36.8 36.2 9.8 39.343 29.363 43 29.37143 29.3126.96.36.1994 48.3 36.7 43.8 40.7) 42.5 42.2 11.6 40.947 29.669 47 29.689 47 29.6188.8.131.52 51.0 37.9 46.5 42.3 44.5 44.4 13.1 44.3|50 29.666 50 29.657 50 29.661.084.073 .157 57.41 43.3 52.4 46.6 50.3 49.5 14.1 48.054 29.787 54 29.787 54 29.787.0821.047.199 62.6 45.8 57.4 50.3 54.2 53.9 16.8 51.7 59 29.662 59 29.675 59 29.668.095.088.183 67.0 51.961.7 55.5 59.4 58.6 15.1 56.4 63 29.867 63 29.890 63 29.879.077 .070.147 69.9 55.4 64.6 59.2 62.6 61.9 14.5 60.7 67 29.911 67 29.899 67 29.905 .070.0581.128 60.2 47.6 55.8 52.5 53.9 54.1 12.6 56.959 29.753 59 29.775 59 29.764.110.079 .189 51.9 40.5 47.6 45.2 46.2 46.4 11.4 52.2 53 29.704 53 29.739 53 29.7211.093 .105.198 41.9 31.6 37.3 35.6 36.8 36.5 10.3 43.0 44 29.594 44 29.594 44 29.59184.108.40.2061 37.0 27.4 33.6, 31.9 32.2 32.8 9.6 40.3 40 29.566 40 29.583 40 29.5220.127.116.11 52.6 40.3 48.0 44.3) 46.4) 46.2 12.3 47.952 29.664152 29.67152 29.618.104.22.168 OL. VI.
Jan. 3.372 .975 6.8 6.5 6.7 33.8 32.7 22.214.171.124.142 86.4 87.1 86.7
2.617 2.800 28.4 13.1 20.8 45.8 44.3 45.0.216 .204) .210 69.9 82.6 76.3
Avr. 25.625/ 20.785 17.2 10.1) 13.6 39.7) 38.9 126.96.36.199).182 77.5 83.9 80.7)
52.0 21.0 17.0 4.0 30.360 28.690 1.100.050| 17 0 44.6 22.4.204.097 100.0 72.6 Feb. 49.5 21.0 16,5 5.0 || 29.900 28.770 .748.030 22 0 42.4 21.01.1911.082 100.0 52.0 Mar. 55.0 26.0 18.0 5.0 30.144 28.892 1.133.030 29 1 44.6 12.01.204 .068 98.0 41.0 April 58.0 31.0 21.0 5.5 30.150 28.935 .453.005 38 0 45.6 22.41.211.097 100.0 44.0 May 63.0 30.0 25.0 5.5 30.060 29.415 365.005 47 3 53.0 7.0.268 .057 96.0 27.0 June 68.0 41.5 23.0 19.0 30.190 29.175 .630 .020 55 5 34.8 31.4 .284.132 94.0 42.0 July 174.0 42.5 22.5 8.5 30.235 29.170.355.025 50 5 64.0 38.4 .381.167 95.0 54.0 Aug. 179.0 47.0 19.0 8.0 30.335 28.740 .375.015) 51 3 64.6 43.0.386.194 97.0 53.4 Sept. 67.5| 38.0 23.0 4.5 30.420 29.020.540 .010 40 2 59.4 32.4 .328.137 98.0 52.4 Oct. 63.0 26.5 22.5 3.0 30.230 29.225 .460.030 27 1 57.6 15.4.309 .070 99.0 47.0 Nov. 50.0 20.5 19.5 5.5 30.165 28.980.685.110 26 0 43.4 19.0 .197 .087 100.0 51.0 Dec. 151.3) 9.5 19.0 2.0 30.295/ 28.840 705.010 17 10 47.4 18.6.225.086 100.0 62.4
appears from the above tables, that the mean temperature of 1819 is about seven-tenths of a degree lower than that of 1818 ; the mean height of the Barometer •014 higher; the quantity of rain 1*772 less; and the mean of Leslie's Hygrometer -2 higher. The mèan daily range of the Thermometer and Barometer is almost exactly the same for both years. The quantity of evaporation exceeds that of 1818 by •729 of an inch. The mean point of deposition, at 10 a. m. is about half a degree lower than the mean minimum temperature, but the coincidence is sufficiently exact to demonstrate the accuracy of Mr Anderson's principles.
Another observation which has been often alluded to in the pages of your Magazine, and which I think an important one, is amply confirmed by the preceding abstract. I allude to the coincidence between the mean of the daily extreme temperatures, and the mean of the temperatures at 10 morning, and evening. The difference for the whole of 1819, amounts only to two-tenths of a degree. For several years preceding I found the mean difference three-tenths,
The temperature of spring-water taken three times a-month, and which gave a result for 1818 coinciding almost exactly with the mean of the daily extremes, is 1.5 degree higher for 1819. It is to be remembered, however, that the great cold of December, which reduced the mean temperature of the air considerably below the usual average for the season, has not yet produced
its full effect on the water. The comparison, therefore, between the two, ought not to be made till that season of the year when the temperatures of the air and the exterior of the earth approach one another, which takes place about the month of May. I have no doubt that then the coincidence will be nearly exact. I am, Sir, your obedient servant,
BARLOW ON MAGNETIC ATTRACTIONS.* The variation of the compass, a sub- was allowed to slumber ; since nothing ject at all times no less interesting of the least conséquence, during that to the philosopher, than useful to the long and enlightened period, was ada navigator, was first discovered, we are ded to our previous knowledge, on told, by Columbus, in his voyage to this interesting subject. It is, indeed, America in 1492; and Professor Gil- true, that several distinguished navilebrand of Gresham College, in 1625, gators observed, during their respecascertained that this variation was it- tive voyages, anomalies in the variaself of a changeable nature. The dis- tion of the compass, altogether inexcovery of these important and very ex- plicable; and, what appears very extraordinary facts, excited a lively in, traordinary, the more pains that was terest, among men of learning and taken by them to discover them, the science, throughout all Europe ; the further did they go away in point of exertions of our celebrated country- theory. Dampier, when off the Cape man, Dr Halley, on this subject, are of Good Hope, where the variation was well known, and need not be here re- truly estimated at 11°, was much peated.
puzzled, and, no doubt, greatly perThe phenomenon of the magnetic plexed, to find only to 38'. Mr dip, or inclination of the needle, acci- Wales, in his second voyage with dentally discovered by Norman in 1592, captain Cook, was surprised and astowas also then a subject of much spe- nished to find, in the English Chanculation and inquiry; and, to render nel, and indeed throughout the voythis law in the magnetic system sub- age, a difference in the quantity of servient to science and navigation, the variation, though observed with the latitude, in any given meridian, was greatest care, of 3o, 4o, 5o, 6o, 7o, attempted to be ascertained by its re- and even 10°. Captain Phipps, aftersults ; but, the delicacy of the instru. wards Lord Mulgrave, during his ment, and experience, very soon prove voyage towards the north pole, found ed its demonstrations erroneous; and, the like differences; which he attriuntil the last voyage of captain Flinė buted to the inaccuracies of the comders, was adverted to more as a matter passes.
“We made,” says he, of curiosity to philosophers, than of veral observations, which we found, utility to navigators.
by those taken at seven in the afterThe diurnal variation of the com- noon, to be 17° 0' west; by others, at pass, first discovered by Mr Graham, three in the afternoon, only 7° 47' who has been followed by Mr Weir- west: I could not account for this gentin, Mr Canton, and, last of all, very sudden and extraordinary dethe indefatigable exertions of Colonel crease," &c. Monsieur Beautemp BeauBeaufoy, likewise excited considerable pré, while in search of the unfortuattention; but though numerous the- nate La Perouse ; Captain Vancouver ; ories have been formed to account for and many others, found the like errors this phenomenon, none, as yet, have of variation, without being able, in any appeared satisfactory to philosophers, way whatever, to account for them; or useful to science, if we except Mr until Captain Flinders, that acute and Barlow's theory, which we here intend penetrating, but unfortunate, man, in shortly to notice.
his last voyage of discovery to Terra From the beginning of the 18th, to Australis, in 1801, 1802, and 1803, the 19th century, this very important, first discovered the true cause prodų. and highly useful, branch of science, cing these hitherto unaccountable dis
* An Essay on Magnetic Attractions : Particularly as respects the Deviation of the Compass, occasioned by the Local Influence of the Guns, &c. With an Easy Practical Method of observing the same in all parts of the World. By Peter Barlow, of the Royal Military Academy. Printed for J. Taylor, Architectural Library, Holborn, London, 1820.
cordances in the variation on ship lished. In this valuable tract* the boardma change in the direction of author, in the last section, has, in a the ship's head. Having ascertained variety of examples wholly incompathis most important truth, it soon oc- tible with the supposition of truth, curred to him, that a local attraction completely exposed the fallacy of this must exist in the ship; which, in con- rule—which Captain Sabine fully cornexion with terrestrial magnetic at- roborates by observations made during traction, acted on the magnetic needle, the late arctic expedition; and which, when placed at the binnacle, with a indeed, is the only thing of the least compound force; and, therefore, he consequence done in that voyage that found by experiments, that in the has added to our previous knowledge northern hemisphere, when the head on this subject. As to the unintelliwas at west, this combined attractive gible paper written by Mr Scorsby, and power drew the north end of the inserted in the Philosophical Transacneedle to the west; and in the south- tions for 1820, Part I., we are comern hemisphere, to the east, of the pelled to say, it is wholly undeserving true magnetic meridian ; This differ. of the least attention, and serves no ence, produced by local attraction, he other end whatever than to bewilder denominated the Deviation."
the reader into a labyrinth of useless Finding the maximum deviation in experiments, which, we much quesBoth hemispheres, when the ship’s tion, whether the author himself head was at west or east; and that rightly understands. How very difthe needle stood right when the head ferent are the experiments and deducwas in a direction with the magnetic tions we now intend briefly to analyse ! meridian-nörth and south ;-what Mr Barlow, author of the work bewas the proportion of deviation, he fore us, an able mathematieian, and asked himself, at the intermediate one of the Professors of the Royal Mipoints, between the east and west and litary Academy, Woolwich, sensible magnetic meridlan? After much la- of how very much real importance a bour and consideration, it appeared to formula, founded on correct principles, him, “ that the errors produced by for correcting the deviation produced local attraction should be proportion- by a change in the direction of the ate to the sines of the angles between ship’s head, in all approachable latithe ship's head and the magnetic me- tudes, would be to science and naviridian ; and, therefore, in order to gation, and, indeed, to mankind in find this proportion, it seemed pro- general, has at length arrived at the bable the following Rule would be conclusion, after a long, laborious, found applicable in all parts of the and patient investigation of the laws world, viz. “ that the error produced of magnetic attraction, which his siat any direction of the ship's head, tuation and place afforded the most would be to the error at east or west, ample opportunity and means for exat the same dip, as the sine of the angle periments, no less honourable to himbetween the ship's head and magnetic self than beneficial to science and pracmeridian was to the sine of eight points, tical navigation. Before we introduce or rudius,
our readers into our author's work, Captain Flinders dying soon after shop, it may be proper they should his return to England, we see no fur- clearly understand what Mr Barlow's ther attempts made either to verify or ideas were, on this subject, before he overthrow the accuracy of this rule, commenced operations; and the theory until 1807, when a small practical on which all ħis future hopes depends work, entitled, “ an Essay on the ed. We shall transcribe his own Variation of the Compass, by W. Bain, words :-" Since the iron of the ves-, master in the royal navy, was pub- sel,” says our author, " and the com
The importance of this work, in a practical point of view, having excited considerable interest, we refer such of our readers as may not have had an opportunity of seeing the book itself, to Brand's Journal of Science' and the Arts, No 7,-Monthly Review, November 1817,--and British Review, November 1819,---who have each treated the work and the author in a popular manner. Indeed, it has always been to us a matter of regret, that Mr Bain should not have been employed in the late Arctic expedition.
+ That this paper should have been inserted, and that of Mr Barlow's rejected, in that No of the Philosophical Transanctions, surprises us a good deal, and cannot well be accounted for.