Sundial

“ Verses on sundials are comparatively scarce compared with short mottoes; and this is surprisingly strange, considering what I would like to term the poetry of “ye horologe,” for there is hardly anything on this earth that is better calculated to call forth from man the very finest expressions relative to our brief life, than the sundial. ”

“ But we live in an age of bustle and excitement, and it is seldom that any day gives an hour of rest and mental relaxation from the worries that kill. But when that hour does come, and we find ourselves at peace in our gardens, far from the maddening crowd, studying the beauties of nature, our gaze is certain to be centred sooner or later upon the sundial, our best companion in that quiet hour ”

“ To-day we introduce the sundial into our gardens more for an ornament than from any wish to add to it a timekeeper, and it is the love of the antique that causes old dials to change ownership and to be set up on new sites, irrespective of the fact that they may have been constructed and set for a different locality. ”

“ Old sundial, you stand here for Time:
For Love, the vine that round your base
Its tendrils twines, and dares to climb
And lay one flower-capped spray in grace
Without the asking on your cold
Unsmiling and unfrowning face. ”

“ To the student of astronomy and mathematics, it will ever appear to be a most natural event that the sundial should have been constructed to record accurately the time of day; and such might doubtless express surprise that the age of the earliest known horologe is not of greater antiquity. ”

“ The sundial, at the present time, is made in many forms, the one usually met with being the horizontal form seen on a pedestal in many gardens. The next is the vertical dial to be seen on many old churches and houses. There are also a number of others, such as the hemispherical, cruciform, cylindrical, polygonal, armillary sphere—commonly known as the “globe”—reclining, inclining, and a great variety of pocket dials. ”

“ He the longest life shall live,
Who makes the most of hours I give.
The shades of night my dial enfold,
Like a story that is told.
Earn thou thy rest,
So shall each hour improved by thee,
Bring what is best continually.
416 INDEX TO PLACES. The sundials all are faithfully represented; the drawings are to suit the book, thus the sundials are introduced into pictures drawn to harmonise with the verses, for the purpose of recording which this work has been compiled. ”

“ The time of day was of less importance when the sundial on the church tower, or on a pillar erected at some convenient place, had to be consulted, when the sun shone it is true, but even then many must have inwardly fretted and rebelled against the uncertainty. ”

“ Solar Time, or Time by the Sun.—To make a sundial which would give correct Sun time was so hard a problem that men had to think about it for a million years before they could solve it and the chances are that then it was invented by a boy. ”

“ Sundials of good make have the hour-lines and other divisions radiating from two centres, which are at a distance apart equal to the thickness of the gnomon, consequently there appears to be two hour lines at XII. o’clock, but really it is one, as the shadow at noon fills the space between the two lines.
A sundial cannot be said to be complete without a motto of some description, and by inscribing one on the dial or pedestal it gives a fitting voice to the dignified dial. ”

“ Let, then, those verses which do commend themselves to the reader be in his or her eyes sufficient warranty for my book.
T. G. W. H.
3 The History of the Sundial.
CHAPTER I. Who shall discover the age of the sundial, or fix with certainty the year in which ye horologe was first invented to record the passing of the day or perchance the hour? The archives of time will never reveal to us the first dial that was invented to aid mortal man to regulate his life and so fulfil his daily task. ”

“ Although the Romans were backward in the science of gnomonics and slow to adopt any particular form of horologe, they eventually constructed many a beautiful dial of varied design. The first sundial was erected in Rome in the year 290 B.C., this being taken from the Samnites by Papirius Cursor. ”

“ One lingers over their ornament with loving regard and forgets their purport. As timekeepers they fell short of the abbey clock, or of the sundial—a perennial stickler for truth when the sun shone. When the long pendulum, under the auspices of Christopher Huygens, commenced swinging, a timekeeper ready to hand eclipsed their gold and enamelled triumphs. But as fashionable baubles they had their continuous evolution, from Thomas Chamberlaine de Chelmisforde to Pinchbeck, and from Tompion to Eardley Norton. ”

“ In other words, the sun—that is, a sundial—is only correct on a few days in each year, and during the intervening times gets as far as a whole quarter hour fast or slow. These variations of the sun from uniform time caused no end of trouble between the astronomers and the fine clockmakers before it was discovered that sun time is subject to such irregularities. ”

“ In northern latitudes the sun is always due south at XII. o’clock by the sundial throughout the year, and in southern latitudes it is always due north at XII. In both hemispheres the sun is always due east at VI. a.m. and due west at VI. p.m.
Sundials can be fixed in dull weather, but a magnetic compass will then have to be employed; and although the fixing is simpler than when the sun is used the result is not so accurate.
The directions are as given here:—
Remove the studs and place the dial on the pedestal ”

“ I wished to see the whole—the first contact, the advance of the moon, and the successive swallowing up of the solar spots, the breaking of the last line of crescent by the lunar mountains into Bailey’s beads, the advance of the shadow through the air, the appearance of the corona and prominences at the moment of totality, the radiant streamers of the corona, the internal structure of the flames, a glance through a polariscope, a sweep round the landscape with the naked eye, the reappearance of the solar limb through Bailey’s beads, and, finally, the retreat of the lunar shadow through the air. ”

“ The solar or astronomical day is the time that elapses between two consecutive noons or midnights; it is consequently longer than the sidereal day, on account of the proper motion of the sun during a revolution of the celestial sphere; but as the sun moves with greater rapidity at the winter than at the summer solstice, the astronomical day is more nearly equal to the sidereal day in summer than in winter. The obliquity of the ecliptic also affects its duration, for in the equinoxes the arc of the equator is less than the corresponding arc of the ecliptic, and in the solstices it is greater. ”

“ If the sun moved uniformly in the equator at the rate of 59′ 8′′.3 every day, the solar days would be all equal; the time therefore, which is reckoned by the arrival of an imaginary sun at the meridian, or of one which is supposed to move in the equator, is denominated mean solar time, such as is given by clocks and watches in common life: when it is reckoned by the arrival of the real sun at the meridian, it is apparent time, such as is given by dials. ”

“ If now we set a pair of dividers or compasses so that the opening shall reach over the exact space on the orbit of one half of the mean solar day, and beginning at the red noon point of one of the four days in the year when the true noon falls at just twelve o'clock—say December 24th—and step the dividers around on the orbit, making a blue point mark at each second step, then as the blue points vary from the red so will the mean time which our clocks keep vary from the true noon of each day of the year. ”

“ But it then became a matter of importance to secure each plate at the proper time of year; for the sun, as we know, travels round the Zodiac among the stars, obliterating by his radiance a large section of the sky for a period of some months, and in this way a particular region of the heavens is apt to “run into daylight,” as the observatory phrase goes, and ceases to be available for photography during several months, until the sun is again far enough away to allow of the particular region being seen at night. ”

“ It is obvious that the habitual employment, by the astronomer priests, of a mirror so placed in the sanctuary as to catch the reflection of the pole-star through an open doorway, would lead to the discovery of the movements of the sun and the positions it assumes during the year. The flashing of a beam of sunlight once a year, at the period of the summer solstice, upon the mirror which constantly reflected the pole-star, would naturally suggest the idea of “the union of the day-sun with the night-sun” and seem particularly impressive as it was at this period that the Nile began to rise. ”

“ If we had been using a telescope during that interval we should have beheld a very interesting spectacle, for sunset on the ‘Bay of Rainbows’ is quite as remarkable, although in a very different way, as sunset on the Bay of Naples. The astronomer, seated amid the lonely gloom of his observatory dome, and watching the change of light and illumination on the surface of the moon, has many an hour of solitary enjoyment of aspects of nature that are quite impossible on the earth, and that frequently lure him into poetic meditations which find no place in his notebook. ”

“ There is, near the equator, a certain indescribable effect of clear, starry night creeping over the earth even while it is still daylight, and almost before one has come to realise that the sun has set: not the usual pale-starred, indigo effect of the sky, but a sense of deep, brooding night that is most subtle and peculiarly hard to catch owing to its shortness of duration. ”

“ When, for instance, at 4 o’clock in the morning—at which time the signs of the weather are observed—the stars stand just above the eastern horizon, they stop up the east, so to speak, and prevent the free passage of the wind. But if the pernicious star in question is at the given time 20° or 30° above the horizon, there is enough space between star and horizon for the wind to be released. This strong wind will last until another influential star arises under the first. ”

“ At noon day we should see the sun like an intensely brilliant globe shining in a sky as black as ebony, like a clear fire in the night seen in the midst of an extensive field, and his rays would show us the adjacent objects immediately around us; but the rays which fall on the objects remote from us would be for ever lost in the expanse of the heavens. ”

“ The general diurnal movement is a movement in right ascension; it is measured upon the Equator. The individual annual movement of the sun is a movement in longitude; it is measured upon the Ecliptic.
The zone, or belt, which the sun seems to trace in its annual march, from the limit of its southern excursion (the winter solstice) to the limit of its boreal excursion (the summer solstice) , and in returning from that limit to the other, after having twice passed through the equinoctial line (or Equator) ,—this zone is marked on the firmament by a belt of constellations known as the Zodiac. ”

“ For only in that position could they cast their shadow, or could the number of the illuminated steps be varied, upwards or downwards, according to the varying altitude of the sun. The only conceivable use of [93] a fixed instrument so placed would be to show the rise and fall of the shadow from day to day, as the Sun on the meridian gradually rose higher between mid-winter and mid-summer, or descended lower between mid-summer and mid-winter, in passing of course through the winter and summer solstices in turn. ”

“ Surely, M'Allister, you must have forgotten that night is brought about by the earth's rotation on its axis, and that the part which is turned away from the sun is in darkness because its light is hidden by the solid body of the earth, while the earth's shadow darkens all the sky. When, by the earth's rotation, that part is again turned to the sun then it becomes daylight. ”

“ Sunlight acts on the moon as it does on the earth, not as on the air; therefore the moon resembles earth rather than air.
c. 19. This is well received, and Lucius refers (a second analogy) to solar eclipses, and in particular to a recent one, to show that the moon, like the earth, can intercept the sun’s light, and is therefore, like it, a solid body. The fact that the track of the shadow is narrow in a solar eclipse is explained. ”

“ The day and the night are the visible divisions of time. The day, in its heat and its aptitude for action, is masculine:—the night, in its moisture and its appropriation to rest, feminine.
Hence, again, the Moon and Venus are esteemed to be nocturnal; the Sun and Jupiter, diurnal; and Mercury, common; since in his matutine position he is diurnal, but nocturnal when vespertine.
Of the other two planets, Saturn and Mars, which are noxious, one is considered to be diurnal, and the other nocturnal. ”

“ These suns, as they rose slowly and steadily, amidst clouds and storms, in their ascendant, so they have not rushed from their meridian to sink suddenly in the west. Like the mildness, the serenity, the continuing benignity of a summer’s day, they have gone down with slow-descending, grateful, long-lingering light ”

“ If we now find this inconspicuous part of the heavens equally honoured by several nations in very ancient times, we shall be led to think either that these nations, independently of each other, happened to observe and mark out the sun’s annual course through the heavens at exactly the same date, and therefore chose the same point as marking the winter solstice; or we must suppose that they derived their calendar and knowledge of the Zodiac from observations originally made by some one civilized race. ”

“ From this it is plain that the stars set a little earlier every day in reference to sun-time: or, that they pass the meridian a little earlier every day in reference to sun-time; and therefore, if we define the sidereal day to be the time that elapses from the passage of a star over the meridian one day to the passage of the same star another day, that interval or the sidereal day will be less than a solar day. ”