50 SCENERY OF THE HEAVENS. 



will infallibly keep the appointment. In countries favoured with a more transparent atmo- 

 sphere than our own, the day-spring, the commencement of terrestrial nature's diurnal 

 audience with the solar presence, is a scene of great combined beauty and magni- 

 ficence. Faint rosy-coloured streamers are early indications of the point of sunrise; 

 these rapidly become more distinct, and are followed by resplendent saffron hues, from 

 that of burnished gold at the horizon, to the lighter shades gradually fading upwards 

 into the pure cerulean of the illuminated sky. A recent pilgrim from the Western 

 world to the sacred sites of the East, during his stay at Athens, went to witness the 

 sunrise from the Acropolis, amid the solemn grandeur of its desolations. Seated 

 within the ruins of the Parthenon, commanding a view of the horizon through the co- 

 lumns of the eastern portico, he awaited from the grey dawn the appearance of the orb 

 of day. Gradually the sky became so resplendent in the direction of the advancing 

 luminary, as to render it impossible to determine the precise point where his presence 

 would be revealed. The tops of the northern mountains caught his beams, and some 

 light fleecy clouds seemed changed into liquid gold, as, hovering over mount Hymettus, 

 they met the rays of the sun. At length, the eye encountered the solar glory, lighting 

 up the columns and marbles of the Parthenon with a silvery splendour. It was one of 

 those moments in the life of man, says Robinson, the traveller in question, that can never 

 be forgotten. In our own latitude, the sunrise is a spectacle of surpassing interest and 

 beauty, as viewed from the summit of Snowdon, or from some eminence overlooking the 

 sea, in a propitious state of the atmosphere. The progressive illumination the varie- 

 gated colours deepening and brightening that are pencilled on the sky the growing 

 distinctness of the superficies, whether field or flood the retreat of mists and vapours 

 glittering in the sunbeams while vanishing before their action; combine to form a scene 

 of visual beauty which has few parallels in the realms of nature. 



Light is sensibly transmitted to us while the sun is below the horizon. This is occa- 

 sioned by the refractive and reflective properties of the atmosphere. By the former, as 

 previously explained, his place in the heavens is raised, and morning and evening, when 

 his lower limb appears to rest upon the horizon, his entire body is actually below it, and 

 would be invisible but for the refraction of hi| rays. This effect is only produced while 

 his declination does not exceed 33', which is rather more than his greatest apparent 

 diameter. At a further distance from the horizon, the power of refraction is not sufficient 

 to elevate his rays so as to cause their direct transmission to the eye. They are then 

 reflected to us from the upper regions of the atmosphere which receives them, causing 

 the morning and evening twilight, the gradual transition from darkness to light, and from 

 light to darkness. It is owing to the particles of air possessing the property of successively 

 reflecting and re-reflecting the solar light, scattering it in every variety of direction, that all 

 those objects are visible to us in the daytime, which are indirectly situated with reference 

 to the luminary. Without it, the cloudless sky at noon, now so blue and brilliant, would 

 present the blackness of darkness, with the exception of the places occupied by the sun 

 and the stars. The latter would be as visible by day as at midnight, while no object would 

 be perceptible, not receiving the direct sunbeams. It is not impossible but that at midnight, 

 in the hour of the deepest gloom, some of the solar influence may be transmitted to us by 

 an infinite number of reflections, so reduced, however, in its amount and power as to be 

 imperceptible. The period of the sensible reflection of light from the sun, or the twilight, 

 is generally supposed to be confined to his depression eighteen degrees below the horizon. 

 The limit of depression, however, at which there is the greatest observed darkness, varies 

 in different climates. In the torrid zone it has been found to be between sixteen and 

 seventeen degrees ; and in France between seventeen and twenty-one. The duration of 

 the twilight is different at every different latitude on the earth, and it varies in the same 



