J. G. M'Pherson

“ When, then, you look at the face of a deep-blue lake on a summer evening—the heavens all aglow with the unrivalled display of colour from the zenith, stretching in lighter hues of glory to the horizon—though to you the calm water appears like a lake of molten metal glowing with sky-reflected light, so powerful and brilliant as entirely to overpower the light which is internally reflected, yet blue is the normal colour of the water: blueness is its inherent hue. ”

“ CHAPTER XVIII AN AUTUMN AFTERGLOW
A brilliant afterglow is welcomed for its surpassing beauty and a precursor of fine fixed weather.
A glorious sunset has always had a charm for the lover of nature’s beauties. The zenith spreads its canopy of sapphire, and not a breath creeps through the rosy air. A magnificent array of clouds of numberless shapes come smartly into view. Some, far off, are voyaging their sun-bright paths in silvery folds; others float in golden groups. Some masses are embroidered with burning crimson ”

“ Even in the country, especially in summer-time, one distinctly notices the great difference in the air of lowland and highland localities. The ten miles change from Strathmore to Glenisla shows a marked difference in the air. Below, it is close, weakening, enervating; above, it is exhilarating, invigorating, and strong.
So people must have a change—at least those who can afford it—for health must be seen to first of all, if one has means to do so. Oh! the blessing of good health! How many who enjoy it never think of the misery of its loss! ”

“ Hence the air is very pure, free from organic germs, intensely exhilarating and buoyant.
Sportsmen are livingly aware of the recuperative power of the Highland air. Perhaps these city men do not benefit so much by the easy walking exercise on the grouse moors as in breathing the splendidly delight-inspiring air. What a change one feels there in a very few hours!
“A change of air” is an old wives’ adage. But much of the weather-lore of our forefathers was based on real scientific principles only now coming to light. Nature is ever true, but it requires patience to unravel her secrets. ”

“ When the flash is from one cloud to another there is sheet-lightning, which is beautiful but not dangerous; but, when the electricity passes from a cloud to the earth in a forked form, it is very dangerous indeed. The flash is instantaneous, but the sound of the thunder takes some time to travel. Roughly speaking, the sound takes five seconds or six beats of the pulse to the mile.
All are now taught at school that it is the oxygen in the air which is necessary to keep us in life. If mice are put into a glass jar of pure oxygen gas, they will at once dance with exhilarating joy. ”

“ Though no fixed conclusions are yet established about the causes of the brilliant auroral display, yet, as the results of laborious observations, we are assured that the stabler centre of our solar system holds in its powerful sway the several planets at their respective distances, supplying them all with their seasonable light and heat, vibrating sympathetic chords in all, and even controlling under certain—though to us still unknown—laws the electric streamers that flit, apparently lawlessly, in the distant earth’s atmosphere. ”

“ After the sun’s broad beams have tired the sight, the moon with more sober light charms us to descry her beauty, as she shines sublimely in her virgin modesty. There is always a most fascinating freshness in the first sight of the new moon. The superstition of centuries adds to this charm. Why boys and girls like to turn over a coin in their pocket at this sight one cannot tell: yet it is done. No [Pg 59] young lady likes to look at the new moon through a pane of glass. And farmers are always confident of a change of weather with a new moon: at least in bad weather they earnestly hope for it. ”

“ All are familiar with the ordinary prognostics of good and bad weather. A “broch” round the moon, in her troubled heaven, indicates a storm of rain or wind. When the dark crimson sun in the evening throws a brilliant bronzed light on the gables and dead leaves, we are sure that there is an intense radiation from the earth to form dew, or even hoar-frost. ”

“ It is well known that, when bodies are exposed to radiant heat, they are heated in proportion to their size; the smaller, then, may be moist, when the larger are dry by radiation. The effect of the sun’s penetrating heat through the cloud is to heat exposed objects above the temperature of the air; and if the objects are of any size they are considerably heated, and retain their heat more, while at the same time around them is a layer of warm air which is quite sufficient to force the water-vapour to leave the dust-particles in the fine rain. ”

“ In our ordinary atmosphere there can be no clouds without dust. A dust-particle is the nucleus that at a certain humidity becomes the centre of condensation of the water-vapour so as to form a cloud-particle; and a collection of these forms a cloud.
This condensation of vapour round a number of dust-particles in visible form gives rise to a vast variety of cloud-shapes. There are two distinct ways in which the formation of clouds generally takes place. Either a layer of air is cooled in a body below the dew-point; or a mass of warm and moist air rises into a mass which is cold and dry. ”

“ Small things must not be overlooked, for great discoveries are sometimes at a man’s very door. Dr. Aitken has shown us this in many of his discoveries which have revolutionised a branch of meteorology. Prudence, patience, observing power, and perseverance in scientific research will do much to bring about unexpected results, and not more so in any science [Pg 13] than in accounting for weather-lore on a rational basis, which it is in the power of all my readers to further. ”

“ In a city like London or Glasgow, where a great river, fed by warm streams of water from gigantic works, passes through its centre, fogs can never be entirely obliterated, for the dust-particles in the air (often four millions and upwards in the cubic inch) will seize with terrible avidity the warm vapour rising from the river. That is the main reason why fogs cannot there be put down. Smoke is being consumed to a great extent; yet we find particles of sulphur remaining, which seize the warm vapour and form fogs dense enough to check all traffic. ”

“ Or even in the town gardens, after a continued snow has been melted away by a soft, western breeze, we are struck with the white, peeping buds of the snowdrop and the finely springing grass in the sward. ”

“ Hence during the night the wind is reversed, until in the morning again the equilibrium is restored and there is a calm, so far as these are concerned. These are therefore called the “land and sea breezes.” Of course, it is within the tropics that these breezes are most marked. By the assistance of other winds, a hurricane will there occasionally destroy towns and bring about much damage and loss of life; but better that hundreds should perish by a hurricane than thousands by the pestilence which, but for the storm, would have done its dire work. ”

“ Soon the earth chills, and the sea is counterbalancingly warm—as sea-water is steadier as to temperature than is land—the air over the sea becomes warmer, and ascends, the current from the land rushing in to take its place. ”

“ But when the temperature [Pg 41] and pressure are not suitable for the formation of what we commonly know as the rain, the fine drops fall into the air under the cloud, where they immediately evaporate from their dust free-surfaces, if the air is dry and warm. This is, in other words, the decay of clouds.
It is a curious fact that objects in a fog may not be wetted, when the number of water-particles is great. It seems that these water-particles all evaporate so quickly that even one’s hand or face is not sensible of being wetted. The particles are minutely small ”

“ From the earliest ages clouds have attracted the attention of observers. Varied are their forms and colours, yet in our atmosphere there is one law in their formation. Cloud-particles are formed by the condensation of water-vapour on the dust-particles invisibly floating in the atmosphere, up to thousands—and even millions—in the cubic inch of air. ”

“ Some of the very fine dust-particles, even when clothed with an exceedingly thin coating of water-vapour, are carried very high; and, looking through a vast accumulation of these, we find the effect of a deep-blue colour.
Why so? Because these particles are so small that they can only reflect the rays of the blue end of the spectrum; and the higher we ascend, the smaller are the particles and the deeper is the blue. But it is also because water, even in its very finest and purest form, is blue in colour. ”

“ The rainfall of a district has a telling effect on the climate. Boggy land produces a deleterious climate, if not malaria. Over the world, generally, the prevailing winds are grand regulators of the climate in the distinctive districts. A wooded valley—like the greatest in Britain, Strathmore—has a health-invigorating power: what a calamity it is, then, that so many extensive woods, destroyed by the awful hurricane twelve years ago, are not replanted!
Some people can stand with impunity any climate; their “leather lungs” cannot be touched by extremes of temperature ”

“ A thick haze may be occasioned by an increased number of dust-particles with little moisture, or of a diminished number of dust-particles with much moisture, above the point of saturation. The haze is cleared by this temperature rising, so as to allow the moisture to evaporate from the dust-particles.
Whenever the air is dry and hazy, much dust is found in it; as the dust decreases the haze also decreases. For example, Dr. Aitken, at Kingairloch, in one of the clearest districts of Argyleshire, on a clear July afternoon, counted 4000 dust-particles in a cubic inch of the air ”

“ This heat the earth retained till evening. As the air chilled, the water-vapour from the warmer earth rose from its surface, and was arrested by the cold surface of the leaves. So cold was that surface that it froze the water-vapour when rising from the earth, and formed hoar-frost in very large quantities. When this happens later on in the season, one may be almost sure of having rain in the forenoon.
As hoar-frost is just frozen dew, I can even more surely convince you of the formation of hoar-frost as rising from the ground by observations made by me at my manse in Strathmore, in June 1892. ”

“ The daily maximum velocity of the wind occurs during the night, the daily differences being greatest in summer and least in winter. A blazing sun in the summer daily pours its rays on the atmosphere, and a thick envelope of cloud has apparently but little influence on the effect of the sun’s rays. Thunder-storms are essentially autumn and winter phenomena, being rare in summer.
According to Mr. Buchanan, the weather on Ben Nevis is characterised by great prevalence of fog or mist. In continuously clear weather it practically never rains on the mountain at all. ”

“ There are not many mountains of this height and of a conical shape; and still fewer can there be where a steady wind, for months together, blows up a valley so as to project the rising morning mist at a suitable height and distance on the western side, to catch the shadow of the peak at sunrise.
The most famous place in Europe for witnessing the awe-inspiring phenomenon is the Brocken, in Germany—3740 feet in height. The only great disappointment there is that the conditions rarely combine at sunrise or sunset to have “the spectre” successful. ”

“ It is radiant heat that is the cause of the remarkable result. The rays of the sun, which strike the upper part of the cloud, not only heat that surface but also penetrate the cloud and fall on the surface of bodies within, generating heat there. These heated surfaces again radiate heat into the air attached to them. This warm air receives the fine raindrops in the cloud, and dissolves the moisture from the dust-particles before the moisture can reach the surfaces exposed. ”

“ If we look at the sky overhead, when cloudless in the sunshine, we wonder what gives the air such a deep-blue colour. We are not looking, as [Pg 75] children seem to do, into vacancy, away into the far unknown. ”

“ In the country it is disagreeable enough; but never so intensely raw and dense as in the city. On the sea, too, the fog is disagreeable and fraught with danger. The fog-horn is heard, in its deep, sombre note, from the lighthouse tower, when the strong artificial light is almost useless. ”

“ So that, though the continued snow cools the air for animals that can look after their own heating, it keeps warm the soil; and vegetation prospers under the genial covering. The fine rich look of the young wheat-blades, after a continued snow has melted, must strike the most careless observer. Instead of the half-blackened tips and semi-sickly blades, which we see in a field of young wheat after a considerable course of dry frost without snow, we have a rich, healthy green which shows the vital energy at work in the plants. ”

“ Many scientific men are decoyed on in the search for truth with a spell unknown to others: the anticipation of the results sometimes amounts to a passion. Many wrong tracks do they take, yet they start afresh, just as the detective has to take several courses before he hits upon the correct scent. When they succeed, they experience a pleasure which is indescribable; to them fame is more than a mere “fancied life in others’ breath.”
Dr. Aitken’s continued experiments, often of rare ingenuity and brilliancy, show that no truth is altogether barren ”

“ It might be more powerfully available than the imagined condensation of a cloud into rain by the reverberation caused by the firing of a range of cannon.
But what is the practical benefit of this information? If electricity deposits smoke, it might be made available in many ways. The fumes from chemical works might be condensed; and the air in large cities, otherwise polluted, might be purified and rendered innocuous. The smoke of chimneys in manufacturing works might be prevented from entering the atmosphere at all. In flour-mills and coal-mines the fine dust is dangerously explosive. ”

“ As the weather changes, the affected patients increase with a rush.
He is of opinion that the supposed rapid spread of influenza on the establishment of anti-cyclonic conditions may be explained in this way. The air in the cyclonic vortex, drawn chiefly from the atmosphere over the ocean, is moist, and contains none of [Pg 110] the contagion; the air of the anti-cyclone, derived from the higher strata, and thus from distant cyclones, descending, blows gently over the land to the nearest cyclone, and, being drier, is more able to carry suspended particles with it. ”

“ It is quite true that many easterly winds are peculiarly moist; all that precede storms are so far damp and rainy; and it is owing to this circumstance that, on the east coast of Scotland, the east winds are searching and carry most of the annual rainfall there. But all of these moist easterly winds, however, soon turn to some westerly point. The real east wind, so much feared by invalids, does not turn to the west; it is exceeding dry. Curious is it that brain diseases, as well as consumption, reach their height in Britain while east winds prevail. ”

“ It is found during the winter months in several parts of the Continent that as the temperature falls the pressure rises, producing anti-cyclones over the cold area; whereas, when the temperature begins to rise, the pressure falls, and cyclones are attracted to the warming area.
Small natural cyclones are often seen on dusty roads, the whirling column having a core of dusty air, and the centre of the vortex travelling along the road, tossing up the dust in a very disagreeable way to pedestrians. Sometimes such a cyclone will toss up dry leaves to a height of four or five feet. ”

“ However, supposing there is any part of the upper air free from dust, it is now found possible, when any of these gases experimented on be present, for the sun to convert them into nuclei of condensation, and permit of clouds being formed in dustless air, miles above the surface of the earth.
In the lower atmosphere there are always plenty of dust-particles to form cloudy condensation, whether the sun shines or not. These are produced by the waste from the millions of meteors that daily fall into the air. ”