The Mongols-who despise the Chinese, and employ their own national name 'Mongol' as the sole mode of expressing the idea of courage and virtue-come to Pekin to sell horses, and sheep with long wool, and flat wide tails. The Mongol caravans are highly picturesque, as they traverse the dusty desert, on which the traveller falls in with them on his way to see one of the wonders of the world, the Great Wall of China. These caravans are marshalled after the immemorial fashion of the East; headed by a chief, to be recognised by his arms; the men perched between the humps of the camels, who walk in single file, each fastened by the head to the tail of the preceding one, and slowly swinging the long pendent bell of bronze, painted scarlet, which hangs at his neck. The men are fierce, proud-looking, and handsome, and their dress is imposing. It consists of long robes of red leather, lined with thick furs, and immense caps of bearskin, with strange coral ornaments.

On the second day's march towards the Great Wall the travellers reach the fortified city of Tchang-Piu-Tchao,' and find it is a filthy hamlet with mud walls. Next morning they come to the five majestic gates of the Valley of the Tombs of the Emperors. This valley, which is all sand, is shut in on the other side by an amphitheatre of lofty mountains, at whose feet, surrounded by green trees, stand thirteen gigantic tombs, arranged in a semicircle. The long avenue which extends from the entrance of the valley to the tomb of the first emperor, a distance of three miles, is marked out, first by winged columns of white marble, then by two ranges of sculptured animals of colossal size: camels, elephants, hippopotami, lions fifteen feet high, and each cut out of a single block of granite, winged dragons, a number of other animals, and then twelve emperors three times the size of life, helmed and cuirassed. What superhuman labor does this wonderful avenue imply! Well may M. de Beauvoir remind us that the men of the age which saw those blocks of granite rolled into the midst of that sandy plain, must have been men who did not consume their lives, like the Chinamen of to-day, in gambling and, opium-smoking dens. At

the end of the avenue are the tombs: each is a temple, in which white and pink marble, porphyry, and carved teak-wood are blended in a tasteful harmony, and with grand, severe lines, very rare in Chinese architecture. The austere splendor of these funereal palaces has undergone no change for nine hundred years; since an entire people in mourning escorted the golden coffin of the Ming emperor on its road between the colossi in granite, the 'howlers' flung themselves down and grovelled before his tomb, and the diggers who laid his ashes in the dust they had dug into were slain upon the spot, lest the secret of the treasures buried with him should be betrayed.

One more night, and Nang-kao is passed, and a wild dark gorge is entered, formed by precipitous mountain sides and the dry bed of a torrent; this gorge opens into a rocky valley, most majestic and forbidding. A chain of walls, surmounted by high turrets and crenulations, runs along the top of the terrible rocks, following their sinuosities like a serpent, far out of sight. At first, the traveller thinks this is the Great Wall; but when he has advanced far upon the difficult road through the valley, he sees the sun shining on two other parallel walls, side by side upon the extreme crest of the tremendous rocks, and standing out in clear profile against the sky. One more plunge into a deep dark gorge, whence the traveller emerges upon a sheet of ice, to find himself confronted by two scarlet kiosks, perched like eagles' nests on the summits of two black rocks, which form a natural gate to a new pass. Flocks of wild ducks and geese fly screaming overhead; for many leagues around, not a human being is visible. A little later, and he has reached the bastion which separates Mongolia from China. and its windows are slightly dilapidated; but the Great Wall, which rises abruptly on the right and left, and winds, ‘a fantastic stone serpent,' along the crest of the principal chain, and over the hills and far away, with its square towers rising at intervals, to break the undulating line, until it passes out of sight in the dim distance, is in perfect repair. As the hands of the builders left it, two thousand years ago, it stands to-day.-Chambers's Fournal.

Its base

THERE are few scientific questions of greater interest than the inquiry whether it is possible to find a means of predicting the weather for a long time in advance. In former ages many attempts were made to solve this problem by a reference to the motions of the heavenly bodies. Other methods of prediction were, indeed, in vogue; but I am not here considering ordinary weather portents, or mere scientific schemes for anticipating the weather of two or three coming days: and with a few trifling exceptions, depending on observations of plants and animals, it is the case that the only wide rules for predicting weather were based on the motions of the sun and moon, the planets and the stars. It must be remeinbered that even astronomers of repute placed faith, until quite recent years, in the seemingly absurd tenets of judicial astrology. We cannot greatly wonder, therefore, if the more reasonable thesis that the heavenly bodies determine weather changes, was regarded with favor. Accordingly we find Horrocks, more than two centuries ago, drawing the distinction here indicated, where he says, that in anticipating "storm and tempest" from a conjunction of Mercury with the Sun, he coincides" with the opinion of the astrologers, but in other respects despises their more puerile vanities." We find Bacon in like manner remarking that "all the planets have their summer and winter, wherein they dart their rays stronger or weaker, according to their perpendicular or oblique direction." He says, however, that "the commixtures of the rays of the fixed stars with one another are of use in contemplating the fabric of the world and the nature of the subjacent regions, but in no respect for predictions." Bacon remarks again that reasonable astrology (Astrologia sana) "should take into account the apogees and perigees of the planets, with a proper inquiry into what the vigor of planets may perform of itself; for a planet is more brisk in its apogee, but more communicative in its perigee it should include, also, all the other accidents of the planets' motions, their accelerations, retardations, courses, stations, retrogradations, distances from the sun, increase and diminution of light,

eclipses, &c.; for all these things affect the rays of the planets, and cause them to act either weaker or stronger, or in a different manner."

It is a remarkable circumstance that systems of weather prediction based on such considerations were not quickly exploded owing to their failure when tested by experience. Yet singularly enough it has scarcely ever happened that any wide system of interpretation has been devised, which has not been regarded with favor by its inventor long after it had been in reality disproved by repeated instances of failure. This remark applies to recent systems as well as to those invented in earlier times. Within the last twenty years, for example, methods of prediction based on the moon's movements, on the conjunctions of the planets, and on other relations, have been maintained with astonishing perseverance and constancy, in the face of what outsiders cannot but regard as a most discouraging want of agreement between the predicted weather and the actual progress of events. Here, as in so many cases of prediction, we find the justice of Bacon's aphorism," Men mark when they hit, and never mark when they miss."

It is noteworthy, indeed, that the very circumstance which appears to present a fatal objection to all schemes of prediction based on the motions of the celestial bodies, supplies the means of imagining that predictions have been fulfilled. The objection I refer to is this,—we know that the weather is seldom alike over very wide regions, while nevertheless the celestial bodies present the same aspect towards the whole extent of such regions, or an aspect so nearly the same as to suggest that the same conditions of weather should prevail if the weather really depended on the position of the heavenly bodies. It appears, then, that the inventor of a really trustworthy system must have a distinct scheme for each part of every continent,-nay, of every country, if not of every county. This objection is not taken into account, however, by the inventors of systems, while the fact on which it depends affords the means of showing that each prediction has been fulfilled. Thus, suppose “bad wea

ther and much wind " have been predicted on a certain day, and that day is particularly fine and calm in London. If this were urged as an objection to the soundness of the system, the answer would run somewhat on this wise-" Unquestionably it was fine in London, but in North Scotland (or in France, or Spain, or Italy, as the case may be) there was very gloomy weather, and in Ireland (suppose) quite strong winds are reported to have prevailed in the afternoon." The readiness with which men satisfy themselves in such cases, corresponds with that mischievous ingenuity wherewith foolish persons satisfy themselves that a fortune-teller had foretold the truth, that a dream had been fulfilled, a superstition justified, and so forth.

The tendency, at present, amongst those who are desirous of forming a scheme of weather prediction, is to seek the origin of our weather-changes in changes of the sun's condition, and by determining the laws of the solar changes to ascertain the laws which regulate changes in the weather.

It may be remarked, in passing, that this new phase of the inquiry does not reject planetary influences altogether. The theory is entertained by many well-known students of science that changes in the condition of the sun are dependent on the varying positions of the planets; so that if it should be established that our weatherchanges are connected with solar changes, we should infer that indirectly the planets in their motions rule the weather on our earth.

I propose now to consider the evidence relating to the sun's influence, and to discuss the question (altogether distinct, be it remarked) whether a means of accurate weather prediction may be obtained if the sun's influence be regarded as demon

strated.

There is one strong point in favor of the new theory, in the fact that the sun is unquestionably the prime cause of all weather changes. To quote the words of Lieut.-Colonel Strange, an enthusiastic advocate of the theory (and eager to have it tested at this country's charge), "there can hardly be a doubt that almost every natural phenomenon connected with climate can be distinctly traced to the sun as the great dominating force, and it is a natural inference (though not, as he says, an unavoidable one) "that the changes, and what we now call the uncer

tainties of climate are connected with the constant fluctuations which we know to be perpetually occurring in the sun itself.” I may proceed, indeed, in this place, to quote the following words in which Colonel Strange enunciates the theory itself which I am about to discuss, and its consequences: "The bearing of climatic changes on a vast array of problems connected with navigation, agriculture, and health, need but be mentioned to show the importance of seeking in the sun, where they doubtless reside, for the causes which govern these changes. It is indeed my conviction that of all the fields now open for scientific cultivation, there is not one which, quite apart from its transcendent philosophical interest, promises results of such high utilitarian value, as the exhaustive systematic study of the sun."

It cannot be doubted, I think, that if anything like what is here promised could be hoped for from the study of the sun, it would be a matter of more than national importance to undertake the task indicated by Colonel Strange. The expense of new observatories for this special subject of study would in that case be very fully repaid. It would be worth while to employ the most skilful astronomers at salaries comparable with those which are paid to our Government ministers; it would be well to secure on corresponding terms the advice of those most competent to decide on the instrumental requirements of the case; and in fact the value of the work which is at present accomplished at Greenwich, great though that value is, would sink into utter insignificance, in my judgment, compared with the results flowing in the supposed case from the proposed "exhaustive and systematic study" of the great central luminary of the planetary

system.

The subject we are to discuss is manifestly therefore of the utmost importance, and cannot be too carefully dealt with. It would be a misfortune on the one hand to be led by careless reasoning to underestimate the chances in favor of the proposed scheme, while on the other it would be most mischievous to entertain unfounded expectations where the necessary experiments must be of a costly nature, and where science would be grievously discredited should it be proved that the whole scheme was illusory.

We note, first, that besides being "the

great dominating force" to which all natural phenomena connected with climate are due, the sun has special influence on all the most noteworthy variations of weather. The seasons are due to solar influence; and here we have an instance of a power of prediction derived from solar study though belonging to a date so remote that we are apt to forget the fact. It seems so obvious that summer will be on the whole warmer than winter, that we overlook the circumstance that at some epoch or other this fact, at least in its relation to the apparent motions of the sun, must have been recognised as a discovery. Men must at one time have learned, or perhaps we should rather say, each race of men must at one time have noticed, that the varying warmth on which the processes of vegetation depend, correspond with the varying diurnal course of the sun. So soon as this was noticed, and so soon as the periodic nature of the sun's varying motions had been ascertained, men had acquired in effect the power of predicting that at particular times or seasons, the weather on the whole would be warmer than at other seasons. In other words, so soon as men had recognised the period we call the year, they could predict that one half of each year would be warmer than the other half. Simple as this fact may seem, it is important to notice it as the beginning of weather prediction; for as will presently appear, it has an important bearing on the more complex questions at present involved in the prognostication of weather-changes.

It became manifest almost as soon as this discovery had been made, that the weather of particular days or even of week and longer periods could not, by its means, be predicted. A week in summer may be cold, and a week in winter may be warm; nor, so far as is even yet known, is there a single part of any year the temperature of which can be certainly depended upon, at least within the temperate zone. In certain tropical regions there are tolerably constant weather variations; but so far is this from being the case in the temperate zones of either hemisphere, that it is impossible to affirm certainly, even that during a week or fortnight at any given summer season there will be one hot day, or that during a corresponding period in the winter there will be one day of cold weather. NEW SERIES.-VOL. XVIII., No. 3

It became manifest also, at an early epoch, that terrestrial conditions must be intimately involved in all questions of weather, since the year in different countries in the same latitudes presents different features. Such differences are of two kinds,-those which have a tendency to be constant, and those which are in their nature variable. For example, the annual weather in Canadian regions having the same range of latitude as Great Britain, differs always to a very marked degree, though not always to the same degree, from that which prevails in this country: here then we have a case of a constant difference due unquestionably to terrestrial relations. Again, when we have a hot or dry summer in this country, warm or damp weather may prevail in other countries in the the same latitudes, and vice versâ; differences of this kind are ordinarily* variable, and in the present position of weather science are regarded as accidental.

Hitherto, weather-science has depended solely on the study of these terrestrial effects as they vary under varying conditions. Modern meteorological research is confined to the record and study of the actual condition of the weather from day to day at selected stations in different countries. It cannot be denied that the inquiry has not been attended with success. At vast expense millions of records of heat, rainfall, winds, clouds, barometric pressure, and so on have been secured; but hitherto no law has been recognized in the variations thus recorded, no law at least from which any constant system of predic

I use this qualifying word, because some differences of the kind are more or less regular. Thus, when there is a dry summer in certain regions in the West of Europe, there is commonly a wet summer in easterly regions in the same latitude, and vice versa, the difference simply depending on the height at which the clouds travel which are brought by the south-westerly countertrade winds. When these clouds travel high, they do not give up their moisture until they have travelled far inland or towards the east; when they travel low, their moisture is condensed so soon as they reach the western landslopes. It is not uncommonly the case again, that when we in England have dry summers, much rain falls on the Atlantic, and our drought is simply due to the fall of this rain before the clouds from the south-west have reached us. More commonly, however, drought in England is due to the delay of the downfall, in consequence of the clouds from the south-west travelling at a greater height than usual.

22

tion for long periods in advance can be deduced.

66

On this point I shall quote first a remarkable saying of Sir W. Herschel's, which appears to me, like many such sayings of his, to be only too applicable to the present state of science. In endeavoring to interpret the laws of weather, we are in the position," Herschel remarks, "of a man who hears at intervals a few fragments of a long history related in a prosy, unmethodical manner. A host of circumstances omitted or forgotten, and the want of connection between the parts, prevent the hearer from obtaining possession of the entire history. Were he allowed to interrupt the narrator, and ask him to explain the apparent contradictions, or to clear up doubts at obscure points, he might hope to arrive at a general view. The questions that we would address to nature, are the very experiments of which we are deprived in the science of meteorology."

The late Professor De Morgan, indeed, selected meteorology as the subject on which, above all others, systematic observations had been most completely wasted, ―as a special instance of the failure of the true Baconian method (which be it noticed is not, as is so commonly supposed, the modern scientific method). "There is an attempt at induction going on," says De Morgan, "which has yielded little or no fruit, the observations made in the meteorological observatories. This attempt is carried on in a manner which would have caused Bacon to dance for joy" (query); "for he lived in times when Chancellors did dance. Russia, says M. Biot, is covered by an army of meteorographs, with generals, high officers, subalterns, and privates, with fixed and defined duties of observation. Other countries, also, have their systematic observations. And what has come of it? Nothing, says M. Biot, and nothing will ever come of it: the veteran mathematician and experimental philosopher declares, as does Mr. Ellis" (Bacon's biographer), "that no single branch of science has ever been fruitfully explored in this way." A special interest attaches, I may remark, to the opinion of M. Biot, because it was given upon the proposal of the French government to construct meteorological observatories in Algeria.

It is well known that our Astronomer Royal holds a similar opinion. De Mor

gan thus quaintly indicates his interpretation of one particular expression of Sir G. Airy's opinion:-" In the report to the Greenwich Board of Visitors, for 1867, the Astronomer Royal, speaking of the increase of meteorological observatories, remarks, Whether the effect of this movement will be that millions of useless observations will be added to the millions that already exist, or whether something may be expected to result which will lead to a meteorological theory, I cannot hazard a conjecture. This is a conjecture, and a very obvious one; if Mr. Airy would have given 234d., for the chance of a meteorological theory formed by masses of observations, he would never have said what I have quoted."

The simple combination of terrestrial considerations with the effects due to the sun's varying daily path having thus far failed to afford any interpretation of the varying weather from year to year, it is natural to inquire whether the variations in the sun's condition from year to year may not supply the required means of interpreting and hence of predicting weatherchanges. We know that the sun's condition does vary, because we sometimes see many large spots upon his surface, whereas at others he has no spots, or few and small ones. We can scarcely doubt that these variations affect the supply of heat and light, as well as of chemical action and possibly of other forms of force; and hence we are certainly dealing with a vera causa, though whether this real cause be an efficient cause of weather-changes remains yet to be determined.

It may perhaps be as well to inquire, however, in the first place, whether any peculiarities of weather can be traced to another circumstance which ought to be at least as efficient, one would suppose, as any changes in the sun's action due to the spots. I refer to his varying distance from the earth. It is known doubtless to all my readers that in June and July, although these are our summer months, the sun is farther away than in December,and this, not by an inconsiderable distance, but by more than three millions of miles. Accordingly, on a summer day in our hemisphere we receive much less heat than is received on a summer day in the southern hemisphere. Or instead of comparing our summer heat with summer heat in the southern hemisphere, we may make