Part 9

It was in the confidence resulting from this masterly achievement that in 1872 some astronomers (among them Professor Alex. Herschel, one of Sir J. Herschel's sons) announced the probable occurrence of a display of meteors when the earth crossed the track of Biela's missing comet. An occurrence of this sort was alone wanting to complete the evidence for the meteoric theory. It had been found that the August Perseids move as if they followed in the track of a known comet; the path of the November Leonides had been shown to be identical with that of another comet; if astronomers could predict the appearance of meteors at the time when the earth should pass through the track of a known comet, even those who could not appreciate the force of the mathematical evidence for the new theory would be convinced by the meteoric display. Possibly such observers would have been satisfied with a meteor shower which would not have contented astronomers. The display must have special characteristics to satisfy scientific observers. The path of a body following Biela's comet being known, and its exact rate of motion, the direction in which it must enter our earth's atmosphere (if at all) is determined. Calculation showed this direction to be such that every meteor would appear to travel directly from the constellation Andromeda,--from a point near the feet of the Chained Lady. A meteor might appear in any part of the sky, but its course must be directed from that point, otherwise it could not possibly be travelling in the track of Biela's comet.

The event corresponded exactly with the anticipations of astronomers. On the evening of November 27, 1872, many thousands of small meteors were seen. In England between 40,000 and 50,000 were counted. In Italy the meteors were so numerous that at one time there seemed to be a cloud of light around the region near the feet of Andromeda whence all the meteor-tracks seemed to radiate. The meteors were unmistakably travelling on the track of Biela's comet. They overtook the earth on a path slanting downwards somewhat from the north--precisely in the direction in which Biela's comet would itself have descended upon the earth if at any time the earth had chanced to reach the part of her path crossed by the comet's when the comet was passing that way.

Strangely enough, a German astronomer, Klinkerfues, seems to have regarded the meteoric display of November 27, 1872, as an actual visit from Biela's comet. He telegraphed to Pogson, Government Astronomer at Madras, 'Biela touched earth on November 27, look out for it near Theta Centauri;' which, being interpreted, means, Biela's comet then grazed the earth, coming from the feet of Andromeda, look for it where it is travelling onwards in the opposite direction--that is towards the shoulder of the Centaur. As Biela's comet had in reality passed that way twelve weeks earlier, the instructions of Klinkerfues were somewhat wide of the mark. However, Pogson followed them, and near the spot indicated he saw two faint cloud-like objects, slowly moving athwart the heavens. These he supposed to be the two comets into which the missing comet had divided. It so happens, strangely enough, that these objects, though moving parallel to the track of the missing comets, were neither those comets themselves, nor the meteor flight through which the earth had passed a few hours before. They were probably somewhat richer meteor clouds, fragments (like the cloud through which our earth had passed) of this most mysterious of all known comets.

To-night, or perhaps to-morrow or next night (for the position of the meteor flights is not certainly known) we shall probably see meteors travelling in advance of the main body. For the earth passes during the next three days across the orbit of Biela's comet, about as far in front of the head as she passed behind the head in 1872. Now, there is no known reason for supposing (on à priori grounds) that meteors get strewn behind a comet's nucleus more readily than in front of it. The disturbing forces which would tend to delay some meteoric attendants would be balanced by forces which would tend to hasten others. As a matter of fact it would seem that the meteor flights which follow a comet's nucleus are commonly denser than those which precede the nucleus. Yet in 1865 many thousands of Leonides were seen which were in advance of the main body forming the comet of 1866. In 1859, 1860, and 1861, many Perseids were seen, which were in advance of the comet of 1862. So that we might fairly expect to see a great number of Andromeds to-night (or on the following nights) even if we had none but the probabilities thus suggested to guide us. But since many were seen on November 27 last, when the head of the comet, now some four months' journey from us, was a whole year's journey further away, it seems probable that on the present occasion a display well worth observing will be seen should fine weather prevail. It will be specially interesting to astronomers, as showing how meteors are strewn in front of a comet. How meteors are strewn behind a comet we already know tolerably well from observations made on the Perseids since 1862 and on the Leonides since 1865.

COLD WINTERS.

During the cold weather of last December (1878) we heard much about old-fashioned winters. It was generally assumed that some thirty or forty years ago the winters were colder than they now are. Some began to speculate on the probability that we may be about to have a cycle of cold winters, continuing perhaps for thirty or forty years, as the cycle of mild winters is commonly supposed to have done. If any doubts were expressed as to the greater severity of winter weather thirty or forty years ago, evidence was forthcoming to show that at that time our smaller rivers were commonly frozen over during the winter, and the larger rivers always encumbered with masses of ice, and not unfrequently frozen from source to estuary. Skating was spoken of as a half-forgotten pastime in these days, as compared with what it was when the seniors of our time were lads. Nor were dismal stories wanting of villages snowed up for months, of men and women who had been lost amid snowdrifts, and of other troubles such as we now associate rather with Siberian than with British winters.

Turning over recently the volume of the 'Penny Magazine' for the year 1837, I came across a passage which shows that these ideas about winter weather forty years ago were entertained forty years ago about winter weather eighty or ninety years ago. It occurs in an article on the 'Peculiarities of the Climate of Canada and the United States.' Discussing the theory whether the clearing away of forests has any influence in mitigating the severity of winter weather, the writer of the article says, 'Many persons assert, and I believe with some degree of accuracy, that the seasons in Europe, and in our own island particularly, have undergone a remarkable change within the memory of many persons now living; and if such really be the case, how few attempts have been made to account for this change, since no great natural phenomenon, like that of clearing away millions of acres of forest timber, and thereby exposing the cold and moist soil to the action of the sun's rays, has recently taken place here; so that if the climate of Great Britain has actually undergone a change, the cause, whatever that may be, must be of a different nature from that generally supposed to affect the climate of North America.' It must be explained that, though in this passage the writer does not speak of a diminution in the severity of the winters, it is a change of that sort that he is really referring to. He had said, a few lines before, that 'some of the older inhabitants of North America will declare to you that the winters are much less severe "now" than they were forty or fifty years ago,' and in the passage quoted he is discussing the possibility of a similar change in Europe, where, however, as he points out, the cause assigned to the supposed change in America has certainly no existence. Since 1830, by the way, the theory has been advanced that the supposed mildness of recent winters may have been caused by the large increase in the consumption of coal, owing to the use of steam machinery, gas for lighting purposes, and so forth.

I believe it will be found on careful inquiry that the change for which forty years ago men sought a cause in vain, and for which at present they assign a perfectly inadequate cause, has had no real existence. The study of meteorological records gives no valid support to the theory of change. Nor is it difficult to understand how the idea that there has been a change has arisen from the changed conditions under which men in middle life, as compared with children, observe or feel the effects of milder weather. A child gives no heed to mild winters. They pass, like ordinary spring or autumn days, unnoted and unremembered. But a bitter winter, or even a spell of bitter weather such as is felt almost every year, is remembered. Even though it lasts but for a short time, it produces as much effect on the childish imagination as a long and bitter winter produces on the minds of grown folk. Looking back at the days of childhood, the middle-aged man or woman recalls what seems like a series of bitter winters, because recalling many occasions when, during what seemed a long time, the snow lay deep, the waters were frozen, and the outdoor air was shrewd and biting.

Before considering some of the remarkable winters which during the last century have been experienced in Great Britain and in Europe generally, I would discuss briefly the evidence on which I base the belief that the winter weather of Europe, and of Great Britain especially, has undergone no noteworthy change during the last century.

If there is any validity in the theory at present in vogue that our winters are milder now than they were forty or fifty years ago, and the theory in vogue as we have seen forty years ago that the winters then were milder than they had been forty or fifty years earlier, it is manifest that there ought to be a very remarkable contrast between our present winter weather and that which was commonly experienced eighty or ninety years since. Now, it so chances that we possess a record of the weather from 1768 to 1792, by a very competent observer--Gilbert White of Selborne--which serves to show what weather prevailed generally during that interval; while the same writer has described at length, in his own happy and effective manner, some of the winters which were specially remarkable for severity. Let us see whether the winters during the last third of the eighteenth century were so much more bitter or long-lasting than those now experienced as common ideas on the subject would suggest.

In 1768, the year began with a fortnight's frost and snow. The cold was very severe, as will presently be more particularly noted. Thereafter wet and rainy weather prevailed to the end of February. The winter of 1768-69 was marked throughout by alternations of rain and frost; thus from the middle of November to the end of 1768 there were 'alternate rains and frosts;' in January and February, 1769, the weather was 'frosty and rainy, with gleams of fine weather in the intervals; then to the middle of March, wind and rain.' The last half of November, 1769, was dry and frosty, December windy, with rain and intervals of frost, and the first fortnight very foggy; the first fortnight of January, 1770, frosty, but on the 14th and 15th all the snow melted and to the end of February mild hazy weather prevailed; March was frosty and bright. From the middle of October, 1770, to the end of the year, there were almost incessant rains; then severe frosts till the last week of January, 1771, after which rain and snow prevailed for a fortnight, followed by spring weather till the end of February. March and April were frosty. The spring of 1771 was so exceptionally severe in the Isle of Skye that it was called the Black Spring; in the south also it was severe. November, 1771, frost with intervals of fog and rain; December, mild and bright weather with hoar frosts; January and the first week of February, 1772, frost and snow; thence to the end of the first fortnight in March, frost, sleet, rain, and snow.

The winter of 1772-73 would fairly compare with the mildest in recent years, except for one fortnight of hard frost in February, 1773. For from the end of September to December 22 there were rain and mild weather--the first ice on December 23--but thence to the end of the month foggy weather. The first week in January, frost, but the rest of the month dark rainy weather; and after the fortnight of hard frost in February, misty showery weather to the end of the first week in March, and bright spring days till April.

There were four weeks of frost after the end of the first fortnight in November, 1773, then rain to the end of the year, and rain and frost alternately to the middle of March, 1774.

In 1774-1775 there seems to have been no winter at all worth mentioning. From August 24 to the end of the third week in November there was rain, with frequent intervals of sunny weather. Then to the end of December, dark dripping fogs. January, February, and the first half of March, 1775, rain almost every day; and to the end of the first week in April, cold winds, with showers of rain and snow.

The end of the year 1775 was rainy, with intervals of hoar frost and sunshine. Dark frosty weather prevailed during the first three weeks of January, 1776, with much snow. Afterwards foggy weather and hoar frost. The cold of January, 1776, was remarkable, and will presently be more fully described.

November and December, 1776, were dry and frosty, with some days of hard rain. Then to January 10, 1777, hard frost; to the 20th foggy with frequent showers; and to February 18, hard dry frost with snow, followed by heavy rains, with intervals of warm dry spring weather to the end of May.

The winter of 1777-78 was another which resembled closely enough those winters which many suppose to be peculiar to recent years. The autumn weather to October 12 had been remarkably fine and warm. From then to the end of the year, grey mild weather prevailed, with but little rain and still less frost. During the first thirteen days of January there was frost with a little snow; then rain to January 24, followed by six days of hard frost. After this, harsh foggy weather with rain prevailed till February 23; then five days of frost; a fortnight of dark harsh weather; and spring weather to the end of the first fortnight in April. The second fortnight of April, however, was cold, with snow and frost.

Similarly varied in character was the winter of 1778-79. From the end of September, 1778, to the end of the year the weather was wet, with considerable intervals of sunshine. January, 1779, was characterised by alternations of frost and showers. After this, to April 21, warm dry weather prevailed.

The winter of 1779-80 was rather more severe. During October and November the weather was fine with intervals of rain. December rainy, with frost and snow occasionally. January 1780, frosty. During February dark harsh weather prevailed, with frequent intervals of frost. March was characterised by warm, showery, spring weather.

November and December, 1781, were warm and rainy; and the same mild open weather prevailed till February 4. Then followed eighteen days of hard frost, after which to the end of March the weather was cold and windy, with frost, snow, and rain. Thus the first two-thirds of the winter of 1781-82 were exceptionally mild, while the last third was cold and bleak.

In November, 1782, we find for the first time in these records an instance of early and long-continued cold. 'November began with a hard frost, and continued throughout, with alternate frost and thaw. The first part of December frosty.' The latter half of December, however, and the first sixteen days of January were mild, with much rain and wind. Then came a week of hard frost, followed by stormy dripping weather to the end of February. Thence to May 9, cold harsh winds prevailed. On May 5 there was thick ice.

The next two winters were, on the whole, the severest of the entire series recorded by Gilbert White, though at no time in the winter of 1783-84 was the cold greater than has often been experienced in this country. White's record runs thus: From September 23 to November 12, dry mild weather. To December 18, grey soft weather with a few showers. Thence to February 19, 1784, hard frost, with two thaws, one on January 14, the other on February 5. To February 28, mild wet fogs. To March 3, frost with ice. To March 10, sleet and snow. To April 2, snow with hard frost.

The winter of 1784-85 was remarkable for the exceedingly severe cold of December, 1784, which will presently be referred to more particularly. From November 6 to the end of the year 1784, fog, rain, and hard frost alternated, the frost continuing longest and being severest in December. On January 2 a thaw began, and rainy weather with wind continued to January 28. Thence to March 15 hard frost; to March 21 mild weather with sprinkling showers; to April 7 hard frost.

After rainy weather till December 23, 1786, came frost and snow till January 7, 1787. Then a week of mild and very rainy weather, followed by a week of heavy snow. From January 21 to February 11, mild weather with frequent rains; to February 21 dry weather with high winds; and to March 10, hard frost. Then alternate rains and frosts to April 13.

Early in November, 1786, there was frost, but thence to December 16 rain with only 'a few detached days of frost.' After a fortnight of frost and snow, came 24 days of dark, moist, mild weather. Then four days (from January 24 to January 28, 1787) of frost and snow; after which mild showery weather to February 16, dry cool weather to February 28, stormy and rainy weather to March 10. The next fortnight bright and frosty; then mild rainy weather to the end of April.

November, 1787, was mild till the 23rd, the last week frosty. The first three weeks of December still and mild, with rain, the last week frosty. The first thirteen days of January mild and wet; then five days of frost, followed by dry, windy weather. February frosty, but with frequent showers. The first half of March hard frost, the rest dark harsh weather with much rain.

The winter of 1788-89 was very severe, hard frost continuing from November 22, 1788, to January 13, 1789. The rest of January was mild with showers. February rainy, with snow showers and heavy gales of wind. The first thirteen days of March hard frost, with snow, and then till April 18, heavy rain, with frost, snow, and sleet. This winter was very severe also on the Continent.

The winter of 1789-90 was as mild as that of 1788-89 had been severe. The record runs thus:--'November to 17th, heavy rains with violent gales of wind. To December 18, mild dry weather with a few showers. To the end of the year rain and wind. To January 16, 1790, mild foggy weather, with occasional rains. To January 21' (five days only) 'frost. To January 28, dark, with driving rains. To February 14, mild dry weather. To February 22' (eight days) 'hard frost.' To April 5 bright cold weather with a few showers.