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with temperature, depth, climate, weather, currents, and possibly even some small difference in the relative proportions of the chemical constituents of the sea itself,-all must operate in affecting the phenomena of life and creation; and it is through the influence of such particulars that we can explain the differences of type in the marine fauna and flora of seas separated from each other only by a few miles of land-as, for instance, the Pacific Ocean and the Gulf of Mexico at the Isthmus of Panama, or the Mediterranean and Red Seas at the Isthmus of Suez.

If there be any such law, it must have been in operation during past geological epochs as well as at the present time; and wherever we can find any stratum containing animal and vegetable remains, marked by a similar facies to that of the animals and vegetables which we now find in any existing region, surely we may draw from them a tolerably correct inference as to the climate and nature of the country in which such bygone forms once lived. If we find, for example, that the fauna and flora of the oolitic period bears a certain resemblance in facies or type to the present fauna and flora of Australia, we may assume that those regions of which the oolitic strata are the debris bore in their time a corresponding amount of resemblance in physical condition to the present state of Australia.

So much for similar conditions of locality producing similar plants and animals. It remains to consider what are the conditions which so influence the creative or vital powers, and how they operate. Can my suggestion of the attraction of resemblance to the character of the birthplace have any bearing here? Its application is certainly less apparent, but, I should say, may still exist. We must remember that there may be, and no doubt are, many points of resemblance which our faculties are unable to appreciate, but which yet exist; and many which, although we cannot nominate, we yet are sensible of. Most men have some idea of their own of the general character of the different continents-something indescribable, but which yet associates well, in their ideas, with the plants and animals which they know to inhabit them. The essential element of some such inappreciable character may be that which, communicated to the whole animal and

NEW SERIES.-VOL. XI. NO. I.-JAN. 1860.

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vegetable creatures of a continent, gives them that general empirical resemblance which we admit, but cannot embody in words or explain to another.

Notes on the Aurora of the 28th August, and several subsequent nights, as observed at Lunenburg, Massachusetts, Lat. 42° 35'. By Professor WILLIAM B. ROGERS. With a Plate.

We place on permanent record in our pages the subjoined very interesting description of the remarkable Aurora borealis of the end of August last, by our esteemed correspondent, Professor William B. Rogers of Boston, United States, in the hope that its publication may assist in the identification, or the co-ordination at least, of some of the phenomena with those witnessed at the same date in other quarters of the globe. Recent intelligence indicates that an auroral condition of the atmosphere, of unwonted brilliancy, prevailed at the same epoch throughout an unprecedented extent of the earth's surface, being visible on the west side of the Atlantic as far south as Havana, and on the east side in many parts of Europe; how far to the west and east, we cannot at present report. What is more worthy of note than even its occurrence within the tropics, is the fact of its appearance, with identity of date, in the southern hemisphere, in Australia, at our very antipodes. A diffusion so nearly world-wide of a disturbance in the electric equilibrium of the earth's atmosphere seems to lend to this aurora the character and interest of a cosmical phenomenon, and to suggest that philosophers must look for its exciting cause either outside of the earth altogether or deep within it. Nothing will so tend to the discovery of the cause, whatever it may have been, as a careful comparison and analysis of the aspects and phases of the aurora, observed simultaneously at many remote localities and faithfully described. The reader will find an account of the phenomenon as it was witnessed on the 28th and 29th of August and 1st and 2d of September at Havana, in an abstract of a paper read before the Académie des Sciences, Paris, by M. Poey, on the 17th October, and printed in the journal called L'Institut; and he will see a mention of an Aurora

Australis on the 28th of August, &c., at Victoria, in the London Illustrated News of the 19th of November.

Letter, Professor W. B. Rogers to Professor H. D. Rogers of Glasgow.

"MY DEAR BROTHER,-The close of the past summer was marked by a succession of auroras, which, for number and magnificence, have rarely been equalled in this latitude. The favourable position of our hill, commanding the whole horizon, led me to note in some detail the varying phases of the phenomenon on the night when it was most brilliant, and to mark its recurrence at other times throughout the period of its continuance. Knowing that you will be curious to compare these observations with the effects which, as I learn, were observed at the same time in Great Britain, I send you a copy of my notes, compiled from memoranda taken at the moment of observation.

"This memorable period of auroras was ushered in by the superb display of the night of Sunday, August 28-9, of which some details are given below. After this the phenomenon was repeated with more or less splendour for the eight following nights, that is, until the night of Monday, September 5-6. Two of these later displays, those of Thursday and Friday, were scarcely inferior in beauty to the first, while that of Friday, in some of its features, was the most interesting of them all. The uniformity with which certain of its phases recurred, and the marvellous exhibition of pulsations which marked it when most brilliant, are described somewhat minutely in the accompanying notes. In all the lesser displays, as in that last mentioned, the formation of the obscure segment in the north, with its marginal bow of light, was the prominent phenomenon; and the shooting up of streamers from this arch was accompanied by an exhaustion of its light. and a breaking up of the dark space, which, after a pause, was reproduced as before.

"For several days during this auroral period, the telegraph wires were observed to be charged; and so powerful were these waves or currents of the induced electricity, that, on some lines, they enabled the operators to correspond without the use of batteries. Between Boston and Portland, the line.

was worked for two hours by the aurora alone. A similar result was obtained between Braintree and Fall River, between Boston and Fitchburg, and on the vast stretch of wire from Pittsburg to St Louis, as well as on other routes, having more or less of an eastern and western direction.

"Aurora of the night of August 28-9.

"A few minutes before 8 P.M. of the 28th, my attention was called to an appearance resembling a number of elongated, thin, slightly luminous clouds, collected chiefly in the eastern and western quarters of the sky, united by others extending over head in nearly parallel directions. These were quickly replaced by converging columns of the same vapour-like aspect, mingled with more transient luminous streamers, clearly showing the auroral character of the phenomenon. Throughout most of the northern half of the sky the stars were dimmed by what seemed to be a luminous haze, which in some places quite eclipsed their light, and which itself glowed changefully with a golden and crimson colouring. These tints, so indescribably delicate and rich, were brightest in the eastern and western quarters of the sky, where they continued to appear in varying flushes overspreading a wide space, until near the close of the first great display of the evening. In the earlier stage, the obscure space on the northern horizon had not assumed the usual arched form, and was sufficiently translucent to show a few flaky clouds floating within its confines.

"At 8.20, this dark space had become more opaque, and had moulded itself into a symmetrical arch, bounded by a broad luminous band. Quickly groups of streamers shifting from place to place arose along the arch, and then appeared in a long array flashing from nearly every point far up into the sky, while similar luminous columns, spreading along the horizon beyond the east and west points, and extending upwards, united with the long beams dimly stretched over from the north to mark out a second obscure segment in the opposite or southern part of the heavens.

"As these luminous columns rapidly brightened and advanced, the southern segment, which they delineated, grew more distinct and regular, forming in a short time a great

arch, whose dark area embraced a much wider space and greater altitude than its counterpart in the northern quarter. From this time the luminous columns rising from the southern arch continued to increase in brightness, while those on the north grew fainter and less regular, and the arch from which they ascended relapsed into a changing shapeless form.

"At 8.50, the southern half of the heavens had become the seat of the most striking phenomena, and so far outshone the north, that the display might well be called an Aurora Australis. Here was seen a vast dark arch, embracing about 130 degrees of the horizon, and rising to a height of 50 degrees, bounded above by a broad luminous zone, from which the intermitting, far-flashing columns of silvery and golden light seemed to emanate. These gradually encroached upon the arch below, which, as it became depressed, drew with it a border of increasing brightness. At the same time, the luminous columns lengthening upwards began to mark a point of convergence south of the zenith, corresponding to the upper pole of the dipping-needle. Sometimes two, sometimes three or four would flash up to this part of the heavens, and, lingering for a moment, would seem to unite around the pole, often leaving, as they retreated or dissolved away, irregular flakes of light encircling the polar point.

These phenomena continued with little general alteration for many minutes, the southern arch slightly declining in height but not in brilliancy, and another but less luminous arch forming in the north, and sending its flashing streamers towards the magnetic pole, whither also continued to converge the golden and crimson beams emanating from the eastern and western quarters of the horizon. After a time, these converging flashes began rapidly to increase in number and brilliancy, encroaching more and more upon the southern and northern arcs of light, until, at about 9.15, the latter were entirely obliterated amid the suddenly increasing splendours that overspread the whole sky.

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At 9.30, the display attained its highest magnificence. The dome of the heavens was hung around with white, and golden and rose-tinted streamers converging from all quarters towards the magnetic pole, and uniting there in a circle of continually varying brilliancy and colour. Over the glow

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