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Updated: June 16, 2025
On the N. there is a winding cleft, and some short crossed clefts in the rugged surface just beyond the foot of the wall, which I have seen with a 4 inch achromatic. The region on the W., imperfectly shown in the maps, includes much unrecorded detail. On the Mare Imbrium S. of Plato is a large area enclosed by low ridges, to which Schroter gave the name "Newton."
But it must be remarked that, although the theoretical possibility of constructing an achromatic lens was investigated by Newton, he certainly came to the conclusion that the difficulty could not be removed by employing a composite objective, with two different kinds of glass. In this his marvellous sagacity in the interpretation of nature seems for once to have deserted him.
She almost seemed to herself not to speak, yet by some inward volition her lips formed the words: "Hope is only a bubble, yet it rims with rainbows whatever we see mirrored in it." "Yes?" he returned, inquiringly. "I was only thinking," replied she, continuing her descent, "that it is worth some pains to keep the bubble unbroken as long as possible." "But facts are such achromatic glasses."
They trudged onwards with slanted bodies through the flossy fields, keeping as well as they could in the shelter of hedges, which, however, acted as strainers rather than screens. The air, afflicted to pallor with the hoary multitudes that infested it, twisted and spun them eccentrically, suggesting an achromatic chaos of things.
My father possessed a very excellent achromatic spy-glass of 2 inches diameter. The object-glass was made by the celebrated Ramsden. When I was about fifteen I used it to gaze at the moon, planets, and sun-spots.
Schmidt shows several low ridges on the N.E. side. In a paper recently published in the Astronomische Nachrichten, Professor W.H. Pickering, describing his observations of the Tycho streaks made at Arequipa, Peru, with a 13 inch achromatic, asserts that they do not radiate from the centre of Tycho, but from a multitude of minute craters on its S.E. or N. rim.
This instrument is the achromatic microscope. For the history of the successive steps by which it became the effective scientific implement we now possess, I must refer you to the work of Mr. Quekett, to an excellent article in the "Penny Cyclopaedia," or to that of Sir David Brewster in the "Encyclopaedia Britannica."
It was thus when the discovery that the refraction and dispersion of light did not follow the same law of variation, affected both astronomy and physiology by giving us achromatic telescopes and microscopes. It was thus when Bradley's discovery of the aberration of light enabled him to make the first step towards ascertaining the motions of the stars.
We now know how these difficulties can be, to a great extent, overcome, by employing for the objective a composite lens made of two pieces of glass possessing different qualities. To these achromatic object glasses, as they are called, the great development of astronomical knowledge, since Newton's time, is due.
Good-bye, Model of all the Virtues! We can spare you now. A little clear perfection, undiluted with human weakness, goes a great way. Go! be useful, be honorable and honored, be just, be charitable, talk pure reason, and help to disenchant the world by the light of an achromatic understanding. Goodbye! Where is my Beranger? I must read a verse or two of "Fretillon." Fair play for all.
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