FORMATION OF ANCHOR-ICE. SMOKY ATMOSPHERE. does not vary much from 45°, and this is about the uniform temperature of the earth at some distance below the surface. While then the mass of the waters of the lake is at 40°, and ice is forming at the top, the earth, beneath the water, is at the temperature of 45°, or 5° warmer than the water. Heat will, therefore, be constantly imparted to the water from beneath, when the temperature of the water is less than 45°. The only effect of this communication of heat to the water from beneath, during the earlier and colder parts of the winter, is to retard the cooling of the lake and the formation of ice upon its surface. But after the cold abates in the end of winter and beginning of spring, so that the lower parts of the ice are not affected by the frosts from above, the heat, which is communicated from below, acts upon the under surface of the ice, and, in conjunction with the sun's rays, which pass through the transparent surface and are intercepted by the more opaque parts below, dissolves the softer portions, rendering it porous and loose like wet snow, while the upper surface of the ice, hardened by occasional frosts, continues comparatively more compact and firm. In this state of things, it often happens that, by a strong wind, a rent is made in the ice. The waters of the lake are immediately put in motion, the rotten ice falls into small fragments, and, being violently agitated, in conjunction with the warmer water beneath, it all dissolves and vanishes in the course of a few hours. There is one phenomenon, which is of common occurrennce in many of our streams, during the coldest part of winter, and which may not at first appear reconcilable with what has been said above, and that is, the formation of ice upon the stones at the bottom of the streams, usually called anchor ice. Anchor ice is formed at falls and places where the current is so rapid that ice is not formed upon the surface. In the case of running water, and particularly where the water is not deep and the current rapid, over a rough bottom, the temperature of the whole mass is probably reduced nearly or quite to the freezing point before any ice is formed; and then, where the current is so rapid that the ice cannot form at the surface, the ice-cold waters of the surface, in their tumultuous de A remarkable phenomenon attending this disintegration of the ice by the influence of the sun's rays, and one which we think worthy of investigation, is its separation into parallel icicles, or candles, as they are sometimes called, extending perpendicularly from the upper to the lower surface of the ice, giving the mass, particularly the lower portions, somewhat the appearance of a honey comb, DARK DAYS. scent, are successively brought in contact with the stones at the bottom, which, themselves, soon become ice-cold, after which they serve as nuclei upon which the waters are crystilized and retained by attraction, forming anchor ice. Smoky Atmosphere.-From the earliest settlement of this country there have been observed a number of days, both in spring and autumn, on which the atmosphere was heavily loaded with smoke. The smoke has generally been supposed to result wholly from extensive burnings in some unknown part of the country. There is no doubt but that much of the smoke often is produced in this way, but it has appeared to us, that, since smoke is not a product, but a defect, of combustion, it may be possible for it to be produced even where there is no fire. We have been led to this conclusion by observing that the amount of smoke has not always been greatest in those years in which burnings were known to be most extensive; and by observing, moreover, that the atmosphere was usually most loaded with smoke in those autumns and springs which succeeded warm and productive summers. These circumstances have led us to the opinion that the atmosphere may, by its solvent power, raise and support the minute particles of decaying leaves and plants, with no greater heat than is necessary to produce rapid decomposition. When, by the united action of the heat and moisture of autumn and spring, the leaves are separated into minute particles, we suppose these particles may be taken up by the atmosphere, before they are entirely separated into their original elements, or permitted to form new compounds. This process goes on insensibly, until, by some atmospheric change, a condensation takes place, which renders the effluvia visible, with all the appearance and properties of smoke. Dark Days.-It sometimes happens that the atmosphere is so completely filled with smoke as to occasion, especially when accompanied by clouds, a darkness, in the day-time, approaching to that of night. The most remarkable occurrences of this kind, within our own recollection, were in the fall of 1819, and in the spring of 1820. At both of these seasons, the darkness was so great, for a while near the middle of the day, that a book of ordinary print could not be read by the sun's light. The darkness in both cases was occasioned principally by smoke, and without any known extensive burnings; but the summer of 1819, is known to have been remarkable for the abundant growth of vegetation. But the most remarkable DARK DAY. INDIAN SUMMER. METEORS. we should expect. When our ancestors arrived in this country, the whole continent was covered with one uninterrupted, luxuriant mantle of vegetation, and the amount of leaves and other vegetable productions, which were then exposed to spontaneous dissolution upon the surface of the ground, would be much greater than after the forests were cut down and the lands cultivated. Every portion of the country being equally shielded by the forest, the heat, though less intense, on account of the immense evaporation and other concurring causes, would be more darkness of this nature, which has occur- | preceding articles, this is precisely what red since the settlement of this country, was on the memorable 19th of May, 1780, emphatically denominated the dark day. The darkness at that time is known to have covered all the northern parts of the United States and Canada, and to have reached from lake Huron eastward over a considerable portion of the Atlantic ocean. It was occasioned chiefly by a dense smoke, which evidently had a progressive motion from southwest to notheast. In some places it was attended with clouds and in some few with rain. The darkness was not of the same intensity in all places, but was so great through near-uniformly distributed, and the changes ly the whole of this extensive region as to of wind and weather would be less frecause an entire suspension of business quent than after portions of the forests during the greater part of the day, where had been removed, and the atmosphere, the country was settled, and in many pla- over those portions, subjected to sudden ces it was such as to render candles as expansions from the influence of the sun necessary as at midnight. Several hypoth-upon the exposed surface of the ground. eses have been advanced to account for It is very generally believed, that our this remarkable darkness, such as an erup- winds are more variable, our weather tion of a volcano in the interior of the more subject to sudden changes, our ancontinent, the burning of prairies, &c., nual amount of snow less and our mean but by the one advanced in the preceding annual temperature higher than when article, it receives an easy explication. the settlement of the country was comThe regions at the southwest are known menced. And causes, which would proto be extremely productive, and to have duce these changes, would, we believe, been, at that period, deeply covered with be sufficient to destroy, in a great measforest sand plants, whose leaves and perish-ure, the peculiar features of our Indian able parts would be sufficient, during their decay, to fill the atmosphere to almost any extent; and nothing more would be necessary for the production of the phenomenon, than a change of atmospheric pressure, which should produce a sudden condensation, and a southwesterly wind. Summers. The variableness of the winds, occasioned by cutting down large portions of the forests, would of itself be sufficient to scatter and precipitate those brooding oceans of smoke, and prevent the long continuance of those seasons of dark and solemn stillness, which were, in ages that are past, the unerring harbingers of long and dreary winters and deluges of snow. Indian Summer.-It has been said, though we do not vouch for its truth, that it was a maxim with the aborigines of this country, which had been handed down Meteors and Earthquakes.—Upon these from time immemorial, that there would subjects Vermont affords nothing peculiar. be 30 smoky days both in the spring and The common phenomenon of shooting autumn of each year; and their reliance stars is witnessed here as in other parts of upon the occurrence of that number in the country, and those uncommon disautumn was such that they had no fears plays which have several times occurred of winter setting in till the number was about the 13th of November, have been completed. This phenomenon occurred observed from various parts of the state. between the middle of October and the In addition to these, several of those rare middle of December, but principally in meteors, from which meteorolites or meNovember; and it being usually attended teoric stones are thrown, have been noby an almost perfect calm, and a high ticed, but the records of them are few and temperature during the day, our ances- meagre. These meteors make their aptors, perhaps in allusion to the above pearance so unexpectedly and suddenly, maxim, gave it the name of Indian Sum- and continue visible for so short a period mer. But it appears that from the com- of time, that it is hardly possible to make mencement of the settlement of the coun- observations sufficiently accurate to furtry, the Indian Summers have gradually nish data for calculating their velocity, become more and more irregular and less distance or magnitude. That most restrikingly marked in their character, un-markable meteor which passed over New til they have almost ceased to be noticed. Now upon the hypothesis advanced in the England in a southerly direction in the morning of the 14th of December, 1807, REMARKABLE METEORS. REMARKABLE METEORS. from the rest of New England, and from Windsor 133 miles and its height 29 miles. and from which fell large quantities of According to the best of our judgment, the meteor was visible three or four seconds, in which time it passed through an arc of near 50° of the heavens. Its ap. parent diameter was about 20', or two thirds that of the moon, and the color of its light was very white and dazzling, like that of iron in a furnace in a state of fusion. It left a long train of light behind it, and just at the time of disappearance a violent scintillation was observed, and the fragments detached continued luminous at considerable distance from the main body of the meteor, but no meteoralites are known to have fallen. Five or six minutes after the disappearance of the meteor, a very distinct report was heard accompanied by a jarring of the earth, like the report of a cannon at the distance of five or six miles. Now, assuming the correctness of the above data, and that the report was given at the time of the scintillation, the distance of the meteor was then between 70 and 80 miles, and its diameter about one third of a mile. Another, and still more remarkable meteor, was seen from this state as well as 3 PT. 1. Several other meteors of this kind have been observed, the most remarkable of which was seen from the northern part of the state and from nearly the whole of Lower Canada, about 4 o'clock in the morning of the 28th of May, 1834. It being a time when people generally were in bed and asleep, comparatively few had the opportunity of seeing it. Many, however, were awakened by its light, and still more by its report. Residing then at Hatley in Canada, which is 15 miles north of the north line of Vermont at Derby, we were suddenly awakened by a noise resembling that of a large number of heavy carriages pavement, and by a shaking of the house, NEW ENGLAND EARTHQUAKES. AURORA BOREALIS appearance at a point a little north of horizon towards a point not far from the west at an elevation of about 35°, passed zenith; but at times it assumes forms as the meridian at a considerable distance various and fantastic as can well be imnorth of the zenith and disappeared in the agined, and exhibits all the colors of the northeast with an altitude of about 25°. rainbow. It is not uncommon that it takes He thought its apparent magnitude to be the form of concentric arches spanning the 8 or 10 times that of the moon, and that heavens from west to east, usually at the it was visible about 10 seconds. It was north, but sometimes passing through the of a fiery red color, brightest when it first zenith, or even at considerable distance appeared, and gradually decreased in brill- to the south of it. At times the meteor is iancy, all the time throwing off sparks, apparently motionless, but it is not an untill it disappeared. About 4 minutes af- common thing for it to exhibit a violent ter the vanishing of the meteor, a rumb- undulating motion like the whipping of a ling or rattling sound, which sensibly flag in a brisk wind. But it is so variable agitated the surface of the lake, com-in its appearance, that it is vain to attempt menced in the point where the meteor its description. We will, however, menwas first seen, and following the course tion a few of the remarkable occurrences of the meteor died away at the point where the meteor vanished. This meteor was vertical on a north and south line,about 50 miles to the northward of Derby in this state, or nearly over Shipton in Canada, and its altitude must have been at least 30 miles, and still the agitation it produced in the atmosphere was such as to break considerable quantities of glass in the windows at Shipton, Melbourne and some other places. The course of this meteor was mostly over an unsettled country. The most remarkable circumstances attending this meteor were the train of smoke which it left behind, and the long continued noise and shaking of the earth. Since the settlement of New England, there have been recorded a considerable number of earthquakes, and several have been noticed in Vermont. The sound accompanying these is usually described as having a progressive motion; and that, and the shaking of the earth have been supposed to be produced by the rushing of steam through the cavities in the interior of the earth, but the effect known to have been produced by the meteor last described, furnishes strong reasons for suspecting that the cause of many, and perhaps of all the earthquakes which have occurred in New England, has been in the atmosphere above instead of the earth beneath. Had this meteor passed without being seen, the sound and shaking of the earth, which it produced, would have been regarded as a real earthquake, and its origin in the atmosphere would not have been suspected. Aurora Borealis.-This meteor has been very common in Vermont, ever since the first settlement of the state; but in some years it is of more frequent occurrence, and exhibits itself in a more interesting and wonderful manner than in others. Its most common appearance is that of streams of white light shooting up from near the of this meteor which have fallen under our own observation, and some of the attending circumstances. On the 12th of October, 1819, at about 7 o'clock in the evening, the Aurora Borealis assumed the form of three luminous resplendant arches, completely spanning the heavens from west to east. The lowest arch was in the north a little below the pole star, the second about midway between the pole star and the zenith, and the third 10° or 15° to the southward of the zenith. These belts gradually spread out till they became blended with each other, and the whole concave heavens was lit up with a soft and beautiful glow of white light. It would then concentrate to particular points whose brightness would equal that of an ordinary parhelion, and around them would be exhibited the prismatic colors melting into each other in all their mellow loveliness. The motions of the meteor were rapid, undulatory and from north to south varying a little towards the zenith. The sky was clear and of a deep blue color where it was not overspread by the meteor. It was succeeded in the morning of the 13th by a slight fall of snow with a northwest wind. The aurora exhibited itself in a manner very similar to the above in the evening of the 3d of April, 1820, and several times since. But the most remarkable exhibition of this meteor, which has fallen under our own observation, was in the evening of the 25th of January, 1837. It first attracted our attention at about half past 6 o'clock in the evening. It then consisted of an arch of faint red light extending from the northwest and terminating nearly in the east, and crossing the meridian 15 or 20° north of the zenith. This arch soon assumed a bright red hue and gradually moved towards the south. To the northward of it, the sky was nearly black, in which but few stars could be seen. Next AURORA BOREALIS. MAGNETIC VARIATION. regarded as an indication of an approaching storm, but, like other signs, it often fails. It is most common in the months of March, September and October, but it is not unusual in the other months. to the red belt was a belt of white light,, This meteor, when very brilliant, is usually and beyond this in that direction, the sky was much darker than usual, but no clouds were any where to be seen. The red belt, increasing in width and brightness, advanced towards the south and was in the zenith of Burlington about 7 o'clock. The Magnetic Variation.-Very few obserlight was then equal to the full moon, and vations have hitherto been made in Verthe snow and every other object from mont for the purpose of determining the which it was reflected, was deeply tinged variation of the magnetic needle, and with a red or bloody hue. Between the these few have generally been made with red and white belts, were frequently ex- a common surveyor's compass, and, probhibited streams of beautiful yellow light, ably, in most cases, without a very corand to the northward of the red light rect determination of the true meridian; were frequently seen delicate streams of and hence they cannot lay claim to very blue and white curiously alternating and minute accuracy. But since such obserblending with each other. The most vations may serve to present a general prominent and remarkable belt was of a view of the amount and change of variablood-red color, and was continually va- tion, since the settlement of the state, we rying in width and intensity. At eight have embodied those to which we have o'clock, the meteor, though still brilliant, had access, in the following table. had lost most of its unusual properties. From repeated observations and from a careful examination of the lines of the original surveys, John Johnson, Esq.was of the opinion that in 1785, the westerly variation at Burlington was about 7° 12' and that it diminished till the year 1805 when it was about 6° 12". From 1805 the variation has been increasing up to the present time, 1842; and is now 954. This would give a mean annual change of variation of 6' since 1805, and of 3 previous to that time. And although he thought the change of variation may not have been perfectly uniform, yet he was of opinion that a table constructed with the above variation would not differ materially from the truth. The following is such a table. Magnetic Variation at Burlington. Year Var.w Year. Var.w Year. Var.w Year. Var.w 1785 7912' 1800 6°27' 1815 7°12' 1830 8°42 1786 7 91801 6 24 1816 7 18 1831 8 48 1787 7 61802 6 21 1817 7 24 1832 8 54 1788 7 31803 6 18 1818 7 30 1833 9 0 1789 7 01804 6 15 1819 7 36 1834 9 6 1790 6571805 6 121820 7 42 1835 9 12 1791 6 54 1806 6 181821 7 48 1836 9 18 1792 6 511807 6 24 1822 7 54 1837 9 24 1793 6 481808 6 30 1823 8 01838 9 30 1794 6 451809 6 361824 8 61839 9 36 1795 6 42 1810 6 42 1825 8 12 1840 9 42 1796 6391811 6 48 1826 8 18 1841 9 48 1797 6 36 1812 6 54 1827 8 24 1842 9 54 1798 6 34 1813 7 0 1828 8 30 1843 10 0 6 301814 7 61829 8 36 1844 10 6 1799 |