since it happens that chloride of silver is sensitive to those rays only in which the corona is strongest, the coronal form disengages itself photographically, from the obliterating splendor which effectually shrouds it visually, by the superior vigor of its impression upon a chloride of silver film.
Now if this ingenious mode of procedure is to be rendered of any practical avail, advantage must, above all, be taken of the finer air of the mountains. This for two reasons. First, because the glare which, as it were, smothers the delicate structure we want to obtain records of, is there at a minimum; secondly, because the violet rays by which it impresses itself upon the “photographic retina”30 are there at a maximum. These, as Professor Langley’s experiments show, suffer far more from atmospheric ravages than their less refrangible companions in the spectrum; the gain thus to them, relatively to the general gain, grows with every yard of ascent; the proportion, in other words, of short and quick vibrations in the light received becomes exalted as we press upwards – a fact brought into especial prominence by Dr. Copeland’s solar observations at Vincocaya, 14,360 feet above the sea-level. Indeed, for all the operations of celestial photography, the advantages of great altitudes can hardly be exaggerated; and celestial photography is gradually assuming an importance which its first tentative efforts, thirty-four years ago, gave little reason to expect.
Thus, in three leading departments of modern astronomy – solar physics, stellar spectroscopy, and the wide field of photography – the aid of mountain observatories may be pronounced indispensable; while in all there is scarcely a doubt that it will prove eminently useful. There are, indeed, difficulties and drawbacks to their maintenance. The choice of a site, in the first place, is a matter requiring the most careful deliberation. Not all elevated points are available for the purpose. Some act persistently as vapor-condensers, and seldom doff their sullen cap of clouds. From any mountain in the United Kingdom, for instance, it would be folly to expect an astronomical benefit. On Ben Nevis, the chief amongst them, a meteorological observatory has recently been established with the best auguries of success; but it would indeed be a sanguine star-gazer who should expect improved telescopic opportunities from its misty summit.
Even in more favored climates, storms commonly prevail on the heights during several months of the year, and vehement winds give more or less annoyance at all seasons; the direct sunbeams sear the skin like a hot iron; the chill air congeals the blood. Dr. Copeland records that at Vincocaya, one afternoon in June, the black bulb thermometer exposed to solar radiation stood at 199°.1 of Fahrenheit – actually 13° above the boiling-point of water in that lofty spot – while the dry bulb was coated with ice! Still more formidable than these external discomforts is the effect on the human frame itself of transportation into a considerably rarer medium than that for existence in which it was constituted. The head aches; the pulse throbs; every inspiration is a gasp for breath; exertion becomes intolerable. Mr. Whymper’s example seems to show that these extreme symptoms disappear with the resolute endurance of them, and that the system gradually becomes inured to its altered circumstances. But the probationary course is a severe one; and even though life flow back to its accustomed channels, labor must always be painfully impeded by a diminution of the vital supply. And the minor but very sensible inconveniences caused by the difficulty of cooking with water that boils twenty or thirty degrees (according to the height) below 212°, by the reluctance of fires to burn, and of tobacco to keep alight, and we complete a sufficiently deterrent list of the penalties attendant on literal compliance with the magnanimous motto, Altiora petimus.
That they will, nevertheless, not prove deterrent we may safely predict. Enthusiasm for science will assuredly overbear all difficulties that are not impossibilities. Dr. Copeland, taking all into account, ventures to recommend the occupation during the most favorable season – say from October to December – of an “extra-elevated station” 18,500 ft. above the sea, more than one promising site for which might be found in the vicinity of Lake Titicaca. For a permanent mountain observatory, however, he believes that 12,500 ft. would be the outside limit of practical usefulness. It is probable, indeed, that the Rocky Mountains will anticipate the Andes in lending the aid of their broad shoulders to lift astronomers towards the stars. Already a meteorological post has been established on Pike’s Peak in Colorado, at an altitude of 14,151 ft. Telescopic vision there is said to be of rare excellence; we shall be surprised if its benefits be not ere long rendered available.
After all, the present strait of optical astronomy is but the inevitable consequence of its astonishing progress. While instruments remained feeble and imperfect, atmospheric troubles were comparatively little felt; they became intolerable when all other obstacles to a vast increase in the range of distinct vision were removed. The arrival of that stage in the history of the telescope, when the advantages to be derived from its further development should be completely neutralised by the more and more sensibly felt disadvantages of our situation on an air-encompassed globe, was only a question of time. The point was a fixed one: it could be reached later only by a more sluggish advance. Both the difficulty and its remedy were foreseen 167 years ago by the greatest of astronomers and opticians.
“If the theory of making telescopes,” Sir Isaac Newton wrote in 1717,31 “could at length be fully brought into practice, yet there would be certain bounds beyond which telescopes could not perform. For the air through which we look upon the stars is in a perpetual tremor as may be seen by the tremulous motion of shadows cast from high towers, and by the twinkling of the fixed stars. The only remedy is a most serene and quiet air, such as may perhaps be found on the tops of the highest mountains above the grosser clouds.”
GOETHE
The highest rank in literature belongs to those who combine the properly poetical with philosophical qualities, and crown both with a certain robust sincerity and common sense. The sovereign poet must be not merely a singer, but also a sage; to passion and music he must add large ideas; he must extend in width as well as in height; but, besides this, he must be no dreamer or fanatic, and must be rooted as firmly in the hard earth as he spreads widely and mounts freely towards the sky. Goethe, as we have described him, satisfies these conditions, and as much can be said of no other man of the modern world but Dante and Shakspeare.
Of this trio each is complete in all the three dimensions. Each feels deeply, each knows and sees clearly, and each has a stout grasp of reality. This completeness is what gives them their universal fame, and makes them interesting in all times and places. Each, however, is less complete in some directions than in others. Dante though no fanatic, yet is less rational than so great a man should have been. Shakspeare wants academic knowledge. Goethe, too, has his defects, but this is rather the place for dwelling on his peculiar merits. In respect of influence upon the world, he has for the present the advantage of being the latest, and therefore the least obsolete and exhausted, of the three. But he is also essentially much more of a teacher than his two predecessors. Alone among them he has a system, a theory of life, which he has thought and worked out for himself.
From Shakspeare, no doubt, the world may learn, and has learnt, much, yet he professed so little to be a teacher, that he has often been represented as almost without personality, as a mere undisturbed mirror, in which all Nature reflects itself. Something like a century passed before it was perceived that his works deserved to be in a serious sense studied. Dante was to his countrymen a great example and source of inspiration, but hardly, perhaps, a great teacher. On the other hand, Goethe was first to his own nation, and has since been to the whole world, what he describes his own Chiron, “the noble pedagogue,”32 a teacher and wise counsellor on all the most important subjects. To students in almost every department of literature and art, to unsettled spirits needing advice for the conduct of life, to the age itself in a great transition, he offers his word of weighty counsel, and is an acknowledged authority on a greater number of subjects than any other man. It is the great point of distinction between him and Shakspeare that he is so seriously didactic. Like Shakspeare
An expression used by Mr. Warren de la Rue.
Optice, p. 107 (2nd ed. 1719.) “Author’s Monitio” dated July 16, 1717.
“Der grosse Mann, der edle Pedagog, Der, sich zum Ruhm, ein Heldenvolk erzogen.”
