68 Philosophical Inquiries.-North West Magnetic Pole. [Jan. the comparative duration of Voyages to distant quarters. Any person may be convinced of this by applying a thread to a ship's supposed course on the projection of the Sphere, called a Chart. By this simple trial, a line to Bengal, passing through Baffin's Bay and Bhering's Straits, will be to a line from England to Beugal, by the Cape of Good Hope, in the proportion of 45 to 33.-Again, a line from England to China, by a North-west Passage, and the same by the Cape and Straits of Sunda, will be in the proportion of the lengths of 39 to 32, nearly. Here we have, independent of the great risk of the navigation, a great addition of run.-The North-east Passage round Nova Zem. bla and Cape Taimuriu, the most Northerly of Russia, has not yet been clearly ascertained; and there is reason to think that there is land to the N.E. of this Cape, towards Bhering's Straits. But even supposing a North-east Passage practicable, a line from England by it, and through these Straits, to China, and the common line through the Straits of Sunda, would be, in relative lengths, nearly in the proportion of 44 to 32. Two persons in making this decisive experiment of comparative measurement, may not go over precisely the same course : but any arising difference will not amount to 1, or 14, and consequently will not militate against the resulting conclusions. In addition to the celebrated Magnetic Authors, mentioned in my former Communication, I omitted the name of Dr. Gilbert, who, in his " Physiologia Nova de Magnete," and in other publications, has displayed experimentally and theoretically, more knowledge of this occult and obscure science, as far as it has arrived, than all the other authors put together. He also adopted the notion of different Magnetic Poles. In necessarily abandoning the supposition of a Southeast and South-west Magnetic Pole, on account of finding no adequate variation contiguous to their imagined sites, the existence of a moving Magnetic Cause round the South Pole also, will remain dubious, till a continued trial of the variation during a series of years, on the nearest Terra Firma to that Pole, shall indicate such conclusion as may be satisfactory to Philosophy. I throw out the idea, because certain anomalies of variation in South latitudes, require some. such supposition. I am aware, Mr. Urban, that the solidity of the earth may be urged against the possibility of a moving Magnetic cause : but what proof have we that the Sphere we live on, is solid beyond the degree of thickness requisite to preserve its form from being materially altered by its rapid motion round the Sun; by its diurnal mo tion round its axis; and by its motion round its common centre of gravity with the Moon? Newton in his chair, proved by science, what the French Philosophers confirmed by actual measurement; viz. the difference between the Equatorial and Polar diameters of the Earth, arising from the projection of the Globe at the Equator, by its rotatory motion. Were the Earth a solid to its centre, this motion on an imaginary axis, would not give it the ascertained form of an oblate spheroid; as a hard solid moving in empty space, cannot be supposed to yield into that shape, by any law of action as yet unfolded by science. The planet Jupiter is above thirteen hundred times the bulk of the Earth; and Saturn, independent of his double ring, is about a thousand times the bulk of our globe. These dimensions are made out by the clearest rules of science. If we apply to these prodigious bodies the reasoning of Newton relative to plastic forms moving variously, there is no ground for concluding that they are solid substances to their centres. If they were, their vast weight would require infinitely more attraction than probably even the sun could furnish. True, nothing is impossible with the Deity, whose laws of Nature are as simple, as they are beautifully efficient, but we honour his name by following such reasoning as Newton's, inferior as he was to infinite beings : "Superior Beings, when of late they saw, A mortal man unfold all Nature's law; Admir'd such wisdom in an earthly shape, And shew'd a Newton as we shew an ape." It is difficult to write on such a subject; but still we are certainly more warranted in concluding that the earth is not a solid throughout, than the reverse. During the next voyage, I take it for granted, that the requisite scientific preparations will be made for commencing to discover whether or not the newlyascertained Magnetic Cause has a movement; and this can only be made out in due process of time. The Dipping Needle to be used should be of a very light construction, and might in its plane carry a very light card, marked as usual, with the whole turning on a point. By means of a graduated circumference round the exact meridian to be laid off, and a scale of minutes on one of the extremities of the needle, this whole contrivance would shew the variation-dip and diurnal variation, while the observations of subsequent periods would mark the alteration or stability of the North-west Magnetic Pole. The whole compass of Science hardly offers a subject of higher interest. JOHN MACDONALD. Summerland-place, Exeter, Jan. 9. own It is a generally-received opinion, that the Seasons of this Country have of late years undergone a great revolution; that our climate has lost much of its former temperature, that our Winters are more severe, and our Summers much colder than formerly; and as we possess no register of the weather previously to the invention of the thermometer, we have no positive data upon which we can rely for determining the question; those, however, who entertain this opinion, adduce various facts in support of it, and, amongst others, they mention the circumstance of our formerly having had our vineyards, from which we manufactured our wines; and they go so far as to assert that our orchards are beginning to fail from the same cause, aud that we shall probably be as destitute of apples as we now are of vineyards, and be obliged to import them from other countries; and, taking all this as a thing not to be questioned or doubted, they endeavour to discover the cause, which they find in the extension of the Polar Ice to the Southward. As one proof, they tell us that formerly the Danes had their colonies in Greenland, where the climate was then of so mild a temperature, as to afford abundant sustenance for man and beast, and that the whole had perished in consequence of the Ice of the Pole having extended itself to the coast, by which all communication was cut off with the interior of the country, and which, by causing a diminution of temperature, had rendered it a barren waste; this certainly is a powerful argument in their favour, indeed we believe the strongest they can adduce, for not only History, but some recent discoveries, in consequence of this barrier of ice having lately given way, render the fact of Colonies having formerly been established there unquestionable, for the remains of their habitations have been found. We are now told that the great Arctic bason has broken up, and drifted into the warmer regions of the Atlantic, and hence they predict that we shall have milder seasons, and a return of our former temperature; now we confess that we are by no means satisfied, nor convinced, either by the arguments or opinions of these gentlemen; on the contrary, we believe that our climate has lost nothing of its former temperature, and that it is at this moment just what it was in the days of Tacitus. That Historian describes Britain in his time as liable to frequent vicissitudes; whether he ever visited it himself, we believe, is unknown, but if he did not speak from local observation, his information was probably derived from Agricola, his near relation, who commanded the Roman legions here for several years, and made a conquest of nearly the whole of this Island, which he circumnavigated completely, as History informs us; and what does that Historian say? he tells us expressly, that it was peculiarly liable to these frequent changes; that there was much more fog and rain than on the neighbouring Continent; that we had less frost and snow, and our summers were considerably cooler than was experienced in Gaul or Germany this we know from our own experience to be the case at this day. The writer of this article is a Septuagenarian, consequently old enough to have witnessed many of the vicissitudes of our inconstant climate, and perhaps has paid more attention to the weather and seasons than most men. We shall proceed to give some remarkable instances of these within the period of more than half a century. In the year 1761 we had an uncommonly dry spring and summer, very much like 1818; the meadows were burnt up, and in many parts of the country the hay failed intirely. The weather changed about the end of July, with some heavy thunder storms, which greatly refreshed the earth, and restored vegetation. An unusual harvest followed, and they were reaping wheat, even in the neighbourhood of Edinburgh, the latter end of July or the first week of August. The succeeding winter had nothing remarkable to distinguish it from our ordinary winters, but that of the following year, 1762-3, was uncommonly cold, severe, and long; it set in attended with much snow early in November, without a break, or any symptom of thaw, till late in February. The next winter was a mild one, but that of 1764-5, was yet more so; there were some few days frost about Christmas, and a little about the middle of February, after which we had constant open weather, with heavy rains and frequent storms from the South-west and West, which continued till the 14th of April. It might naturally have been expected that such a winter as this would have been followed by an early spring. No such occurrence, however, took place; it was kept back by a series of cold rains and tempests, which put a complete check to vegetation. The year 1790, was ushered in with weather unusually mild, and an early spring; the gooseberry bushes were in bloom, the elms had began to show forth their leaves. We witnessed the elder in complete leaf on the 6th of February, and gathered the blossom of the hawthorn in our own grounds on the 10th of April that year. But the year 1794 was, perhaps, the most remarkable of any that had oecurred for centuries; for that year we seemed 70 Philosophical Inquiries.-Variation of the Seasons. seemed to have changed our climate for that of Italy or Spain. Many instances of these vicissitudes of our climate have since taken place, and must be in the recollection of many individuals which it would be superfluous to quote. Some years ago, we had such a succession of cold summers and backward harvests, that the shooting season was postponed from the first to the middle of September, by Act of Parliament, and continued in force till the seasons came round to their ordinary course. The summers of 1816 and 1817, were so cold, bleak, and wet, that the harvest did not commence till late in September, even in the more Southern parts of the island'; and in several places the corn never ripened at all, particularly in Scotland. The summer of 1818 was remarkable for drought and heat, scarcely a drop of rain falling from May till late in September; and the face of the country was so completely scorched by the Sun, that it presented a spectacle more like the arid plains of Hindostan than the verdant fields of Britain. We have adduced the above observa. tions, in order to show how far the opinion entertained of the deterioration of the temperature of our climate is well founded or otherwise. The Roman historian says, it was such in his time; and the Monkish historians of the middle ages assure us it was the same in their day, and thus confirm their assertions. They relate various instances of rigorous winters; one mentions a winter which commenced in November, and continued till the middle of April and another tells us of a severe frost at Midsummer, which destroyed the corn and fruits, and produced a famine. The weather and seasons seem to depend entirely upon the prevailing winds: if Easterly winds predominate during the winter months, we are sure to have severe frosts and backward springs; if they occur at later periods, we experience cold summers and backward harvests; but if Southerly winds prevail, we then experience the reverse, when the continent becomes heated by the powerful influence of a summer's sun. If the wind comes from the South or South-east, then we feel oppressed with extreme heat, as was the case some few years ago, when the thermometer rose for two successive days to 924 degrees; the wind was from the South-east, and if its course could have been traced, would probably have been found to have been an emanation of the Sirocco of the Mediterranean, which is well known to be a hot blast from the African deserts, somewhat diluted and softened by blending itself with the more temperate atmosphere of the European continent. Our insular situation too, doubtless, is [Jan. another, perhaps the principal cause of these variations of seasons and climate, and subjects us to more humidity than the countries of the Continent inore distant from the Atlantic ocean. Accordingly, when a Westerly wind predominates in winter, we have heavy rains and stormy weather; and when, unattended with these, we have a mild temperature, and nothing to remind us of winter but the shortness of the days whilst in the same latitudes, upon the neighbouring Continent, the rivers and waters are bound up in ice. At the sea side, the weather in the month of January 1817 was so unusually mild, that the thermometer ranged the greater part of the month between 50 and 58, and on one day rose to 60. The wind was from the South-west, and it probably came from the vicinity of the Tropic. Such appear to be the real causes of the varieties of season we so frequently experience; but why these only occur occasionally, and are not uniform, would puzzle the wisest to account for. The two cold and wet summers of 1816 and 1817, have by some been imputed to the disruption of the Arctic ice, which by drifting by the tides and winds down the Atlantic, had chilled the atmosphere to a great extent, and extended its influence to us. This, however, appears perfectly visionary; for had that been the cause, how will they account for those varieties in our seasons for the last fifty years and more, when no such event was known to have taken place. We can easily believe, that these immense bodies of ice might lower the temperature of the air in their immediate vicinity, but this would be too inconsiderable to have any influence upon the atmosphere of our Island. Besides, it is to be observed, that these have been found nearer to the American continent than the British shores, and yet we have no information that any change has taken place in the temperature of America; but after all, great as they are said to be, the largest of them are mere specks, minute points floating and drifting in that vast body of water the Atlantic, too insignificant to operate any sensible change on its surrounding atmosphere. That these have proceeded from the Arctic regions, is unquestionable; they may be part of the ice which had so long barred all access to the coast of Greenland, or they may be fragments detached from the main body of the Polar ice, by storms and tides, or both. But the two expeditions of 1818 have fully demonstrated, that the main body of ice has sustained no sensible diminution, that it was found compact and united in every part, as before, all the way between Spitzbergen and Greenland, presenting every where an insurmountable surmountable barrier not to be passed; nor indeed, were they able to penetrate so far to the Northward as many former na. vigators. What then, let us ask, becomes of the fancied amelioration of the climate of Britain, which certain Northern Philosophers predict, and would persuade us to look for from this supposed disruption and dispersion of the ice of the Polar regions? It is allowed, likewise, that all these islands of ice have been encountered by late navigators far to the West. Now experience teaches us, that our hottest weather proceeds from Southerly winds, not from the West or North-west, where these have been generally discovered; and it was from this quarter the wind came during the dry and hot spring and summer of 1818. Yet most of these floating islands of ice, the supposed cause of our two cold summers and late harvests of 1816 and 1817, must still exist; for it would take years to melt them under the Tropick. But we are told, that we once had vineyards, which no longer exist, and that our orchards have become less productive. With respect to the former, as we do not admit any diminution of temperature to have taken place in our climate, we consider that we are equally capable of having them at present. We know that the common grape ripens with us in most years: and will any one say, that we could not have made our own wines in 1818 if we had had vineyards? But the loss of them must be sought for in other causes. From the changeable nature of our climate, the produce of our vineyards must have always been uncertain, and their culture hazardous and expensive. And when we had obtained considerable acquisitions in the Southern parts of France, it was found that we could always obtain our wines cheaper and of better quality, and in any quantity, from that part of our empire, than we could afford to raise them at home; and to that cause alone do we impute the neglect and ultimate loss of our vineyards, which were grubbed up to make room for a more certain and more profitableculture: nor have we the smallest doubt, but that if due encouragement were given, they might be again established. The present high price of foreign wines strongly encourages the attempt; but no encouragement is to be expected from Government, which would countenauce a measure so highly detrimental to the revenue. Besides, we all know there is a fashion even in wines, and the public taste has been so long habituated to those of France and other countries, that it might be long before the public prejudice would yield to the produce of our own vineyards. not There are anomalies of Season in all climates of the earth, and in all countries where the Seasons are most regular.-The periodical rains sometimes fail in Tropical countries, and famine ensues, as happened in Bengal, in the years 1768 and 1769, when they failed partially the first, and almost totally the second; the famine of 1770 was the consequence. There are likewise certain current opinions, both as to climate and weather, which, however generally admitted, are quite unfounded, and have long since classed with many other vulgar errors which require to be eradicated; for there is nothing more dif ficult than to combat long-established prejudices. W. Y. March 16, 1819. PYROLIGNEOUS ACID. At the recent Anniversary of the Whitehaven Philosophical Society, two specimens of meat cured with the pyroligneous acid were exbibited. They were prepared on the 7th of September, 1819. One was bung up at home, and the other sent out by a vessel to the West Indies, to try the effect of climate upon it, and brought back on the return of the ship to that port. Both specimens were pronounced by all present who tasted them, to be perfectly fresh, sweet, and fit for use after a lapse of 15 months. PLANET VESTA. The recently-discovered planet Vesla may now be perceived with a telescope of moderate power, in the constellation of Cancer; it appears like a star of the fifth or sixth magnitude. GEOCENTRIC AND HELIOCENTRIC TABLES. "The Chevalier Theodore Carezzini, a Piedmontese, has invented two kinds of round tables, which he calls geocentric and beliocentric tables, and by their aid, a person without any knowledge of mathematics can, in a very short time, thoroughly observe the course of the stars, and explain the celestial phenomena. Ladies and youths, whom the inventor bas instructed in his method, have, without much previous knowledge of astronomy, satisfactorily solved various problems respecting the sun, the moon, the planets, fixed stars, eclipses, &c. By means of these instruments, you may, in the open air, obtain a meridian line in a few minutes; and, in a journey by land, never miss the direction to the North. You may also learn the hour during the night without a watch. It is remarkable, that in the country the geocentric table may appear in the shape of an astronomical garden, of whatever size you please." SELECT SELECT POETRY. THE LAMENT OF WOBURN *. HAIL! sepulchre of mighty dead, Congenial to the Poet's tread; Thine is the glen I love to pace, Thine is the tale I love to trace ; Dear are thy walls, thy thronged town, Remembrance of thine old renown, And though thy Names have pass'd away, They leave behind a beamy ray. Yes, Woburn, tho' thy cloister'd pile, Thy groined roof, thy fretted aile, With holy Abbots, great and just, Are mingled in one common dust! Yet hast thou glories-thou canst claim The memory of unsullied fame: Strange turn of fate! the orphan child O'er thine obscurity had smil'd, Nor curs'd the glories yet they tell, That rose but as his parent fell. Peace gilds that roof, yet once that wall It was a sad, a dreary day Where was the Russell in that hour, 'Tis past-the trumpet's martial tone Brac'd thee with valour scarce thine own; Unequal to her foemen's might Pale Woburn bore the shock of fight. And as a torrent o'er the corn He comes-the Victor comes-his eye I will not paint the woes, the shame And while such joys her name can shed, TO THE RAINBOW. By T. CAMPBELL. TRIUMPHANT arch, that fill'st the sky When storms prepare to part, I ask not proud philosophy To teach me what thou art. Betwixt the earth and Heaven. |