Climate winds, bring for the most part cold, dry, wholesome wea ther; and in the same degree that the others relax and sink, these brace and elevate the animal system. The east and west winds are neither remarkable for their strength nor their long continuance; nor, indeed, are they marked with any striking peculiarity. Seldom do calms, for any length of time, prevail here; and the winds, from whatever quarter they blow, and in whatever season, are seldom or never tempestuous, but often loud and strong; and this circumstance has an evident tendency to render the climate salubrious. Through the whole islands rains fall in considerable quantity; but on the west coast, on account of its superior height, by far the greatest quantity falls. During the winter, when in other parts of the kingdom the land is locked up in frost, and deep buried in snow, rains more commonly prevail here, and are either so constant, or recur so soon, that they render it inconvenient to travel either by land or water; and, besides drenching the cultivated fields, and hurting the roots of the grass, introduce diseases among sheep, horses, and black cattle. Snows are neither so frequent, nor in such quantity; but they come with considerable violence, and generally from the north-west and south-east quarter of the heavens; and though what falls in the course of a year may not be much short of the quantity in other northern districts, it continues only a few days at a time on the surface of the earth, owing perhaps not only to the greater warmth, but also to the vapours that are constantly rising from the sea, and floating in the atmosphere.

A peculiarity of the climate, with respect to the season of snow and hail, merits some attention. Some parts of the month of June, which in Britain is well known to be of a pleasant and genial warmth, is here not only often colder than the preceding months, but almost as much so as any

winter month. For about two weeks, and even some- Climate. times more, about the middle of that month, the wind blows from the north strong and piercing, accompanied with snow and hail showers, which drive domestic animals to seek shelter; clothe the fields with a dreary aspect, by checking the progress of the young plants, and blasting their buds and their blossoms, and to a stranger would seem to threaten the islands with famine. As soon as that period is past, the wind veers round, warm showers, suceeed, which revive the tender herbage, that now recovers its former bloom and verdure; the whole tribe of animals again rejoice; and the heart of the husbandman is gladdened with the prospect of future plenty. The cause of this extreme, and seemingly unnatural cold, evidently is the dissolving of the immense fields of ice in the Northern Ocean which happens at that season, and the consequent evaporation. About forty years ago the north wind waft. Black snow, ed over the ocean, what is still recollected by the old people by the name of the black snow, which at the time struck the inhabitants with terror and astonishment. was afterwards known that an eruption of Mount Hecla in Iceland had at that time occurred; and it is probable that this snow had derived its hue from the smoke sent forth by the volcano, or by the combustion of the substances consumed by the melted matter which it cast forth. It is known that the ashes cast forth by Etna and Vesuvius have been carried by the winds to the banks of the Nile.

It

Thunder and lightning are seldom observed here in summer, even in the hottest weather, but most commonly in winter; not, indeed, when the temperature is mild and the sky serene, but when the elements are in commotion. When it blows, rains, hails, or snows, thunder and lightning are frequently the consequence. To whatever cause we may ascribe their appearance at this season, it seems

Climate. to have no influence in rendering them either more violent or more destructive. They are less so here than in other places. They are not accompanied with hailstones of such vast magnitude; nor have they such a tremendous glare, nor such loud and awful peals, as in more soutbern climates.

Notwithstanding these irregularities, the climate possesses one quality superior to what is found in more favoured countries. As the islands stretch far to the north, it might have been expected they would have experienced all the inconveniences that arise from the extremities of heat and cold that are felt under the same parallel in either the old or the new continent. This, how ever, is by no means the case; for while the inhabitants of Hudson's Bay and St Petersburgh are alternately panting with heat, or shivering with cold, the inhabitants of the Orkneys enjoy a temperature comparatively mild and moderate. In proof of this, it may be observed, that the me dium heat, as appears by the springs, amounts to forty-five degrees; and the whole range between the extremes of the cold in winter and heat in summer is from twenty-five to seventy-five degrees of Fahrenheit's thermometer. The range of the barometer is three inches. Hence the few epidemical disorders which occur as the consequence of extremes of temperature, the good health and vigour which the people often enjoy to an advanced age, and the instances that are sometimes met with of longevity.

Around their whole coasts, the land, with a few exceptions, may be descried at the distance of ten leagues, where the water is in depth fifty-two fathoms. So near the shore as one league, the depth of water is between forty and fifty fathoms; but on the opposite side of the group, at the same distance from land, the depth of the water does not exceed thirty-two fathoms. The floodtide, in most places, comes from the north-west; and when

no obstacles from land, rocks, or shallows, intervene, di- Climate. rects its course to the east, south-east, or south, according as it is new made, half run, or approaching to still water. At full and new moon it is high water about half an hour after nine, when the ordinary spring tides rise eight feet perpendicular, and the extraordinary ones fourteen; and at the quadratures the usual neap tides rise three and a half, and such as are uncommon above six feet in height. The greatest rapidity of the spring tides, even in those channels where they run quickest, is nine miles in an hour ; and the neap tides have only about a fourth part of that velocity.

If these spring tides be either at their greatest height or their lowest, the water continues still for the space of only half an hour, and in the neap tides it remains one hour and a half. From whatever quarter ships come, there is almost at all times an easy and ready access to such as are acquainted with the proper channels: and as soon as they have got within the precincts, however stormy the weather may be, or however shattered their condition, little or no difficulty will arise to their finding an excellent harbour. For one part of the year, the night is nearly as fit as the day for entering the harbours; for so far do the islands extend to the north, and such is the effect of having no land immediately beyond them, that the twilight is in general so bright, for two months in the summer, as to enable a person, with the ordinary powers of vision, to read in the house at midnight with the utmost facility. In winter, indeed, the sun is only four hours above the horizon; but neither does the darkness, even at that season, either much retard or endanger the entrance of ships, or their sailing among these islands; for the moon, from the reflection of the water, shines with such an uncommon đẹVOL. V.

C

Climate.

realis.

gree of splendour, that not only the little islands, but even the rocks and tides, are almost as conspicuous in the night as in the day. But even in the long nights, and when the moon does not shine, light from a different source seasonably arises to facilitate navigation, by dispell ing the darkness that would otherwise overspread these Aurora bo- coasts. This is the aurora borealis, now very improperly denominated the northern lights, since by late discoveries they have been found to belong equally to both hemispheres. Here they happily appear, both more frequently, and with greater splendour, than in most other regions; for during the harvest, winter, and spring months, they arise almost every unclouded night, and often shine with the most magnificent brilliancy. The light of the moon at her quadratures sometimes, on such occasions, scarcely equals them in illuminating the friths and the islands.

Between the setting of the sun and the close of the twilight, they commonly make their first appearance in the north, issuing, for the most part, from behind the clouds, like a fountain of pale light, the form of which is undefined; and they continue in this state, a little above the horizon, sometimes only for a short period, and at other times for the space of several hours, without any motion that can be discovered. They form themselves one while into an arch, the height of which is about thirty degrees, and its breadth about sixty; and the pillars on which it is supported several times broader than the rainbow; and so long as they retain this shape they are without any sensible motion. At other times they extend farther over the heavens, rise much higher, assume a greater variety of shapes, and discover a dusky hue, with a motion that is slow but perceptible. Very often they exhibit an appearance quite different, and spread themselves over the whole heavens, diffusing every where a surprising degree of light, and exhibiting the most beautiful phenomena.