“In the extreme north of the British Isles, the warmest month is August, and the temperature of September, if it does not exceed, is nearly equal to that of June. But at Stykkishólm, July is the warmest month, and the temperature of September is 1°·6 colder than that of June. Another point of difference between Iceland and Scotland is that at Stykkishólm, the mean temperature of April and that of November are the same, viz., 33°·1, whereas in Scotland April is 44°·7 and November 40°·3, or April is 7°·4 warmer than November.
“Hence the striking peculiarity of the climate of this part of Iceland is: During the cold half of the year the seasons are longer delayed than in any part of Great Britain. At Greenwich the mean temperature of April, as compared with November, being 6°·5 warmer; at York, 4°·9; at Aberdeen, 3°·9; at Bressay, Shetland, 0°·8; but at Stykkishólm, 0°·0. On the other hand, during the summer months the seasons at Stykkishólm are not delayed as in Shetland and Orkney, but resemble in this respect the eastern district of Great Britain.
“The great annual increase of temperature takes place from April to June—the increase of April being 5°·3, of May 6°·7, and of June 4°·8, and the great annual decrease from September to November—the decrease of September being 4°·2, October 6°·3, and of November 4°·6.
“But the most remarkable feature in the Icelandic climate is the great differences which occur in the temperature of the same month from year to year. This is seen in the highest and lowest temperature of each month during the twenty-six years. Thus, as regards March, the mean temperature in 1846 was 40°·1, but in 1866 it was only 12°·4, thus showing a fluctuation of 27°·7 in the mean temperature of March. The mean monthly fluctuation in the first four months of the year amounts to 22°·9, and for the whole twelve months 14°·9. As regards Scotland, the largest difference for any month during the past fifteen years was 11°·4—the temperature of December 1857 being 44°·9, and of the same month 1870 being 33°·5. In Scotland, the average of the whole twelve months is only 7°·1, or less than half of Iceland. These singular fluctuations of temperature are readily explained by the position of Iceland with respect to the Arctic regions on the one hand, and to the Atlantic with its warm currents on the other. As more than usual prevalence of easterly winds rapidly and greatly depresses the temperature by bringing to its coasts the cold, if not also the frozen regions. On the contrary a prevalence of south-westerly winds disperses the cold, and pours over the island the genial warmth of the Atlantic. This fluctuating character of the season is frequently very disastrous, it being evident that such summers as that of 1866, whose mean temperature was only 42°·9, will well-nigh altogether prevent the growth of vegetation.”
The veteran observer Hr Thorlacius has laid down the following rule: “The great and sudden diminution of pressure which characterises the winter months is the outstanding feature of the meteorology of Iceland.”[92] The barometric mean during twenty-five years at 37 feet above the sea is 29·602. There are two annual maxima of pressure, the greater in May and the lesser in November; whilst the minima are in January and October. The average yearly rainfall closely agrees with the lower parts of the Scottish Lothians—between 1856-68 the mean was 26·81 inches; the maximum (1868) being 34·23, and the minimum (1867) 21·28. The greatest amount fell in autumn and winter—in October 3·16 inches, and in May 1·41. The amount of melted snow, annually registered, ranges from 4 to 12 feet; the mean of twelve years is 7·43; the maximum (1863) is 12·21, the minimum (1867) 4·76. The snowy days average 82 per annum, and the greatest falls are in January, 1·40; in February, 1·34; in December, 1·24; and in March, 1·18. During seven of the twelve years no snow appeared in June; during ten none in July; during eleven none in August; and during five none in September. The severest storm remembered was in 1868; snow began on January 15, and lasted till the end of March, making 7·14 inches. With one or two exceptions, Greenland ice annually showed itself at Stykkishólm between 1859-69. Thunderstorms were very variable. None were registered between February 1860 and August 1861 (included), but sixteen during the six months between November 1853 and April 1854. Of 111 thunderstorms in twenty-three years nearly half were in December (twenty-five) and January (twenty-seven); two occurred in May and July, none in June and August. In the Færoes, also, thunderstorms are wintry, not summery: the reason seems to be that when the peaks are bare, electricity is equally distributed; but when they are invested with snow, a bad conductor, the local congestion relieves itself by discharges. Thunder is said to sound, as we might expect, unusually loud, the effect of rocky hill and stony dale.[93]
3. The climate of Iceland, if not pleasant, is assuredly one of the most wholesome. All the English travellers upon the island in the summer of 1872 agreed that Anglo-Indians on “sick leave” should prefer a tour in the north to the debilitating German Bäder, or to the fantastic hydropathic establishments which are best suited to riotous health. Consumptive patients, and those suffering from constitutional and nervous debility, have of late years been diverted to the dry, cold, and bracing air of Canada, instead of the parts preferred by their fathers—Montpelier, with its dreadful Vent de bise; Pau, where the people describe their year as eight months of winter and four of l’enfer; Pisa, where Johannum and Barahút—the hot and cold places of punishment—seem to meet; and bilious Madeira, with its enfeebling, warm milk-and-water air, which may relieve the one-lunged, but is sadly trying to those with two. In Iceland throughout summer the stimulus of light is never wanting; rich, oily fish can always enter into the bill of fare; and the evidence is in favour of “free ozone,” whose absence has accounted for the presence of cholera.[94] Hence phthisis hardly appears amongst the diseases of the islanders, although, when transported to warmer regions, they are as liable to it as natives of more genial climes. And whilst in Russia an overcoat may be necessary during the height of summer, in Iceland tourists walk about bare-headed at midnight.
There is a regular tide round the island, ebbing (Icel. fjara) and flowing (Icel. flóð) according to the rule of six hours. It sets into the Fjörðs, but in the offing it subtends the shore. According to old observers, these movements are stronger at the full and change, and strongest at the equinoxes. As every wind must blow more or less from the sea, those which pass over the least expanse of land bring rain condensed by the cold heights. Upon the coast there is a kind of daily trade following the summer sun’s course, like that known in Norway.[95] Cyclones are apparently wanting, but history records the most violent volcanic hurricanes; mountain squalls are the rule, and the smoke-gale of water-dust reminds us of the Continental Gauskuld, caused by the Finn-Lapp Magician sending forth his fly. In Iceland, as all the world over, the uplands are warmer than the lowlands—a fact well known to the ancients, but apparently puzzling to the modern traveller. “What is remarkable,” says Henderson (i. 104), “I found the temperature of the atmosphere twelve degrees warmer in this hyperborean region than it was below in the valley.” Yet it is easy to understand that whilst heated air rises, cold sinks; moreover, that, as a rule, there is more water, and consequently more evaporation, in lowlands than in highlands.
The mists (Mistar) are of the three kinds described by the Rev. G. Landt (Færoe Islands, London, Longmans, 1810): (1.) Skadda, or white cumulus on the hill-tops, supposed to show wet weather; (2.) Bolamjorkie, the vapour-belt which girdles the mountain flanks; and (3.) Mokyer (Icel. Thoka), the common fog of England.[96]
The Aurora Borealis, which the pagans held to be an emanation of the Deity—a nimbus encircling some mighty brow—and in which Greenland sees ghosts playing with walrus’ heads, is expected to appear in mid-August, but of course not so splendidly as in winter. The author never saw either streamers or zodiacal light. Uno Von Troil (p. 54) makes the former show from all quarters, but especially from the southern horizon. Metcalfe (p. 385) asserts that it ranges from north-east to south-west, and there is a popular idea that the focus is more easterly than it was a decade ago. In the Færoes it flashes either from west and north-west to east, or from east and north-east to west. The streamers are bluish-yellow, gold-coloured, and red; rarely blue, green, and scarlet. The latter are called Lopt-eldr[97] or lift-fire, which shows the sky aflame. It comes with strong winds and drifting snows, and, as in most hyperborean parts, it betokens great carnage over the place where it rises. Icelanders can no longer make the aurora draw nearer by whistling to it.
The Alpen-glow, also called the evening aurora, is often a glorious spectacle when the reflection of the blood-red west, showing that the sun has just set, falls upon craggy hill and lowland slope, lighting up every house and field to a distance of five or six miles, and washing colour over the daguerrotyped outlines, usually so hard and sharp. When distant objects seem near in most countries men predict rain, here the rule apparently fails. The “Vetrar-braut,” or course of winter (Milky Way), is by no means so bright as some travellers have described it. In heathen times its appearance was used to forecast the hard months, especially as fortune-telling was part of the great autumnal feasts and sacrifices. The author never saw in Iceland the phosphorescent water supposed to betray the presence of electricity and ozone, nor the fulgor brutum seu spurium of romantic meteorologists. The rainbow (Icel. Regnbogi Nikuðs,[98] or of “Old Nick”) is of course common; the twilights strike the stranger from the northern temperates as being unimportant like those of the tropics; and there is a name for the mirage or heat-reek, Hillingar, or Upp-hillingar, when rocks and islands look as if lifted (“up-heaved”) from the level of the sea. The common meteors are the Moorild or moor-fire of Norway (ignis labentes seu fatui), here called Hrævar-eldr[99] and Snæljós. Castor and Pollux in Christian times either became Saint Elmo’s (San Telmo’s) flames, or connected themselves with Saints Nicholas and Clare; hence the Corpo Santo, and hence our “corpusance,” frequently observed by the circumnavigator Pigafitta (A.D. 1519-1522). The old English sailor regarded them as Will-o’-the-wisps intimately related to a certain Davy Jones. The others are the Gýgjar-sól (gow-sun) or Auka-sólir, mock sun (parabolia); and paraselenæ or lunar halos, with Rosabaugr, or storm-rings, literally “sleet-rings,” the effect of minute ice spiculæ, or, perhaps, metallic particles, in the upper air refracting the light, and producing rainbow-hued circles and ovals, which often bisect one another. Water-spouts, the typhons of the Greeks, caused by the suction of clouds highly charged with electricity, have been observed. We read of fire-balls or shooting-stars (Viga-hnöttur or Stjörnuhrap); of electric flames and red-hot globes (volcanic bombs) discharged with loud detonations during eruptions; and the people still believe in the “fire-vomiting” of their craters. Modern science explains the phenomenon by the reflection of the brilliant, glowing, glaring lava and the red-hot scoriæ, upon the dust and ash column, and upon the “smoke-clouds,” which are really steam and other vapours. Yet M. Abich declares that in the Vesuvian eruption of 1834, he distinctly saw the flame of burning hydrogen, and this, indeed, might be expected.