Light is one of the most wonderful and beneficial, and at the same time one of the most mysterious agents in the material creation. Though the sun from which it flows to this part of our system is nearly a hundred millions of miles from our globe, yet we perceive it as evidently, and feel its influence as powerfully, as if it emanated from no higher a region than the clouds. It supplies life and comfort to our physical system, and without its influence and operations on the various objects around us, we could scarcely subsist and participate of enjoyment for a single hour. It is diffused around us on every hand from its fountain the sun; and even the stars, though at a distance hundreds of thousands of times greater than that of the solar orb, transmit to our distant region a portion of this element. It gives beauty and fertility to the earth, it supports the vegetable and animal tribes, and is connected with the various motions which are going forward throughout the system of the universe. It unfolds to us the whole scenery of external nature—the lofty mountains and the expansive plains, the majestic rivers and the mighty ocean; the trees, the flowers, the crystal streams, and the vast canopy of the sky adorned with ten thousands of shining orbs. In short there is scarcely an object within the range of our contemplation, but what is exhibited to our understanding through the medium of light, or at least bears a certain relation to this enlivening and universal agent. When we consider the extreme minuteness of the rays of light, their inconceivable velocity, the invariable laws by which they act upon all bodies, the multifarious phenomena produced by their inflections, refractions and reflections, while their original properties remain the same; the endless variety of colours they produce on every part of our terrestrial creation, and the facility with which millions of rays pass through the smallest apertures, and pervade substances of great density, while every ray passes forward in the crowd without disturbing another, and produces its own specific impression—we cannot but regard this element as the most wonderful, astonishing and delightful part of the material creation. When we consider the admirable beauties and the exquisite pleasures of which light is the essential source, and how much its nature is still involved in mystery, notwithstanding the profound investigations of modern philosophers, we may well exclaim with the Poet:—
“How then shall I attempt to sing of Him
Who, light himself, in uncreated light
Invested deep, dwells awfully retired
From mortal eye or angel’s purer ken;
Whose single smile has, from the first of time,
Filled, overflowing, all yon lamps of heaven,
That beam for ever through the boundless sky.”—Thomson.
The eye is the instrument by which we perceive the beautiful and multifarious effects of this universal agent. Its delicate and complicated structure, its diversified muscles, its coats and membranes, its different humours possessed of different refractive powers, and the various contrivances for performing and regulating its external and internal motions, so as to accomplish the ends intended—clearly demonstrate this organ to be a master-piece of Divine mechanism—the workmanship of Him whose intelligence surpasses conception, and whose Wisdom is unsearchable. ‘Our sight (says Addison) is the most perfect and delightful of all our senses. It fills the mind with the largest variety of ideas, converses with its objects at the greatest distance, and continues the longest in action, without being tired or satiated with its proper enjoyments. The sense of feeling can indeed give us a notion of extension, shape, and all other ideas that enter the eye, except colours; but at the same time it is very much strained, and confined in its operation to the number, bulk and distance of its particular objects. Our sight seems designed to supply all these defects, and may be considered as a more delicate and diffusive kind of touch that spreads itself over an infinite multitude of bodies, comprehends the largest figures, and brings into our reach some of the more remote parts of the universe.’
Could we suppose an order of beings endued with every human faculty but that of sight, it would appear incredible to such beings—accustomed only to the slow information of touch—that by the addition of an organ consisting of a ball and socket, of an inch diameter, they might be enabled, in an instant of time, without changing their place, to perceive the disposition of a whole army, the order of a battle, the figure of a magnificent palace, or all the variety of a landscape. If a man were by feeling to find out the figure of the Peak of Teneriffe, or even of St. Peter’s church at Rome, it would be the work of a lifetime. It would appear still more incredible to such beings as we have supposed, if they were informed of the discoveries which may be made by this little organ in things far beyond the reach of any other sense—that, by means of it we can find our way in the pathless ocean—that we can traverse the globe of the earth, determine its figure and dimensions, and delineate every region of it—yea, that we can measure the planetary orbs, and make discoveries in the sphere of the fixed stars. And, if they were farther informed that, by means of this same organ, we can perceive the tempers and dispositions, the passions and affections of our fellow-creatures, even when they want most to conceal them—that when the tongue is taught most artfully to lie and dissemble, the hypocrisy should appear in the countenance to a discerning eye—and that by this organ we can often perceive what is straight and what is crooked in the mind as well as in the body—would it not appear still more astonishing to beings such as we have now supposed?[33]
Notwithstanding these wonderful properties of the organ of vision, the eye, when unassisted by art, is comparatively limited in the range of its powers. It cannot ascertain the existence of certain objects at the distance of three or four miles, nor perceive what is going forward in nature or art beyond such a limit. By its natural powers we perceive the moon to be a globe about half a degree in diameter, and diversified with two or three dusky spots, and that the sun is a luminous body of apparently the same size—that the planets are luminous points, and that about a thousand stars exist in the visible canopy of the sky. But the ten thousandth part of those luminaries, which are within the reach of human vision, can never be seen by the unassisted eye. Here the TELESCOPE interposes, and adds a new power to the organ of vision, by which it is enabled to extend its views to regions of space immeasurably distant, and to objects, the number and magnitude of which could never otherwise have been surmised by the human imagination. By its aid we obtain a sensible demonstration that space is boundless—that the universe is replenished with innumerable suns and worlds—that the remotest regions of immensity, immeasurably beyond the limits of unassisted vision, display the energies of Creating Power, and that the Empire of the Creator extends far beyond what eye hath seen or the human imagination can conceive.
The telescope is an instrument of a much more wonderful nature than what most people are apt to imagine. However popular such instruments now are, and however common a circumstance it is to contemplate objects at a great distance which the naked eye cannot discern, yet, prior to their invention and improvement, it would have appeared a thing most mysterious, if not impossible, that objects at the distance of ten miles could be made to appear as if within a few yards of us, and that some of the heavenly bodies could be seen as distinctly as if we had been transported by some superior power, hundreds of millions of miles beyond the bounds of our terrestrial habitation. Who could ever have imagined—reasoning a priori—that the refraction of light in glass—the same power by which a straight rod appears crooked in water, by which vision is variously distorted, and by which we are liable to innumerable deceptions—that that same power, or law of nature, by the operation of which the objects in a landscape appear distorted when seen through certain panes of glass in our windows, that that power should ever be so modified and directed as to extend the boundaries of vision, and enable us clearly to distinguish scenes and objects at a distance a thousand times beyond the natural limits of our visual organs? Yet such are the discoveries which science has achieved, such the powers it has brought to light, that by glasses ground into different forms, and properly adapted to each other, we are enabled as it were to contract the boundaries of space, to penetrate into the most distant regions, and to bring within the reach of our knowledge the most sublime objects in the universe.
When Pliny declared in reference to Hipparchus, the ancient astronomer, ‘Ausus rem Deo improbam annumerare posteris stellas,’—that ‘he dared to enumerate the stars for posterity, an undertaking forbidden by God,’ what would that natural historian have said, had it been foretold that in less than 1600 years afterwards, a man would arise who should enable posterity to perceive, and to enumerate ten times more new stars than Hipparchus ever beheld—who should point out higher mountains on the moon than on the earth, who should discover dark spots, as large as our globe, in the sun, the fountain of light—who should descry four moons revolving in different periods of time around the planet Jupiter, and could show to surrounding senators the varying phases of Venus? and that another would soon after arise who should point out a double ring of six hundred thousand miles in circumference, revolving around the planet Saturn, and ten hundreds of thousands of stars which neither Hipparchus nor any of the ancient astronomers could ever descry? Yet these are only a small portion of the discoveries made by Galileo and Herschel, by means of the telescope. Had any one prophetically informed Archimedes, the celebrated geometrician of Syracuse, that vision would, in after ages, be thus wonderfully assisted by art—and further, that one manner of improving vision would be to place a dark opake body directly between the object and the eye—and that another method would be, not to look at the object, but to keep the eye quite in a different, and even in an opposite direction, or to stand with the back directly opposed to it, and to behold all the parts of it, invisible to the naked eye, most distinctly in this way—he would, doubtless have considered the prophet as an enthusiastic fool or a raving madman. Yet these things have been realized in modern times in the fullest extent. In the Gregorian reflecting telescope an opake body, namely the small speculum near the end of the tube, interposes directly between the eye and the object. In the Newtonian Reflector, and in the diagonal eye-pieces formerly described, the eye is directed in a line at right angles to the object, or a deviation of 90 degrees from the direct line of vision. In Herschel’s’ large telescopes, and in the Aerial Reflector formerly described (in pp. 311-325) the back is turned to the object, and the eye in an opposite direction.
These circumstances should teach us humility and a becoming diffidence in our own powers; and they should admonish us not to be too dogmatical or peremptory in affirming what is possible or impossible in regard either to nature or art, or to the operations of the Divine Being. Art has accomplished, in modern times, achievements, in regard to locomotion, marine and aërial navigation, the improvement of vision, the separation and combinations of invisible gases, and numerous other objects, of which the men of former ages could not have formed the least conception. And even yet, we can set no boundaries to the future discoveries of science and the improvements of art; but have every reason to indulge the hope that, in the ages to come, scenes of Divine mechanism in the system of nature will be unfolded, and the effects of chemical and mechanical powers displayed, of which the human mind, in its present state of progress, cannot form the most imperfect idea. Such circumstances likewise should teach us not to reject any intimations which have been made to us in relation to the character, attributes, and dispensations of the Divine Being, and the moral revelations of his will given in the Sacred Records, because we are unable to comprehend every truth and to remove every difficulty, which relates to the moral government of the Great Ruler of the universe. For, if we meet with many circumstances in secular science, and even in the common operations of nature, which are difficult to comprehend—if even the construction of such telescopes as we now use, would have appeared an incomprehensible mystery to ancient philosophers—we must expect to find difficulties almost insurmountable to such limited minds as ours, in the eternal plans and moral arrangements of the “King Immortal and Invisible,” as delineated only in their outlines, in the Sacred Oracles—particularly those which relate to the origin of physical and moral evil, the ultimate destiny of man, and the invisible realities of a future world.
The UTILITY of the telescope may be considered in relation to the following circumstances.
In the first place, it may be considered as an instrument or machine which virtually transports us to the distant regions of space. When we look at the moon through a telescope which magnifies 200 times, and survey its extensive plains, its lofty peaks, its circular ranges of mountains, throwing their deep shadows over the vales, its deep and rugged caverns, and all the other varieties which appear on the Lunar surface, we behold such objects in the same manner as if we were standing at a point 238,800 miles from the earth in the direction of the moon, or only twelve hundred miles from that orb, reckoning its distance to be 240,000 miles. When we view the planet Saturn with a similar instrument, and obtain a view of its belts, and satellites, and its magnificent rings, we are transported, as it were, through regions of space, to a point in the heavens more than nine hundred millions of miles from the surface of our globe, and contemplate those august objects, as if we were placed within five millions of miles of the surface of that planet.[34] Although a supernatural power, sufficient to carry us in such a celestial journey, a thousand miles every day, were exerted—it would require more than two thousand four hundred and sixty years, before we could arrive at such a distant position; yet the telescope, in a few moments, transports our visual powers to that far distant point of space. When we view, with such an instrument, the minute and very distant clusters of stars in the Milky Way, we are carried in effect through the regions of space to the distance of five hundred thousand millions of miles from the earth; for we behold those luminaries through the telescope nearly as if they were actually viewed from such a distant point in the spaces of the firmament. These stars cannot be conceived as less than a hundred billions of miles from our globe, and the instrument we have supposed brings them within the two hundredth part of this distance. Suppose we were carried forward by a rapid motion towards this point, at the rate of a thousand miles every hour, it would require more than fifty-seven thousand years, before we could reach that very distant station in space to which the telescope, in effect, transports us. So that this instrument is far more efficient in opening to our view the scenes of the universe than if we were invested with powers of locomotion to carry us through the regions of space, with the rapidity of a cannon ball at its utmost velocity; and all the while we may sit at ease in our terrestrial apartments.