Magnifier

“ And should the observer think that anything is to be gained by a higher magnifier than 150, let him use the eye-lens only of that power. I have obtained many exquisite views of sun-spots with a single lens, and, instead of purchasing new eyepieces, a real advantage will be derived in adopting the plan suggested. There will be a smaller field and more colour about the image, but the improvement in definition is considerable, and more than balances these disadvantages. ”

“ In these cards the surface is nearly homogeneous, that is to say, free from fibers, and the point of the metal pencil may be made as sharp as a needle, but to utilize these conditions to the fullest extent, it is necessary to aid the eye, and a magnifier is, therefore, brought into use. Under a powerful glass the hand may be so guided by the eye that the writing produced cannot be read by the unaided vision. ”

“ To examine any object accurately, view it first through a magnifier that will shew the whole at once, and afterwards inspect the several parts more particularly with one of the greatest magnifiers; for [117] thus you will gain a true idea of the whole, and all its parts: and, though the greatest magnifiers can shew but a minute portion of any object at once, such as the claw of a flea, the horn of a louse, &c. yet by gently moving the slider that contains your object, the eye will gradually see the whole ”

“ By a shallow magnifier he will also discover those parts which merit a further investigation. Objects that are transparent will bear a much greater magnifying power than those that are opake.
Every object should, if possible, be examined first in that position which is most natural to it: if this circumstance be neglected, very inadequate ideas of the structure of the whole, as well as of the connection and use of the parts, will be formed. If it be a living animal, care must be taken not to squeeze, hurt, or discompose it. ”

“ A low power should be used at first, which may be changed for a somewhat higher one when the object has been found. But in no case will the use of really high magnifiers be found advisable. It is, of course, simply impossible with the tail, for which the naked eye is the best instrument, nor can the coma bear any degree of magnification, though occasionally the nucleus may be sufficiently sharply defined to bear moderate powers. ”

“ Fig. 1.—Tripod Magnifier Fig. 2.—Watchmaker’s Loupe FOLDING MAGNIFIER
The folding magnifier (Fig. 3) of one or more lenses is mounted in such a way that, when not in use, the lenses fold up like the blade of a knife, and when so folded are effectively protected from abrasion by the upper and lower surfaces of the folder.
Fig. 3.—Folding Magnifier Fig. 4.—Reading Glass READING GLASSES
Reading glasses (Fig. 4) are large simple magnifiers, often six inches in diameter. The lens is encircled with a metal band and provided with a handle.
[5]
Fig. ”

“ The true colour of objects cannot be properly determined when viewed through the deepest magnifiers; for, as the pores and interstices of an object are enlarged, according to the magnifying power of the glasses made use of, the component parts of its substance will appear separated many thousand times farther asunder than they do to the naked eye ”

“ Fig. 4, K, a concave speculum of polished silver, in the center of which a lens is placed. On the back of this speculum a male [119] screw, L, is made to fit the brass ring I, Fig. 3. Four of these specula of different concavities, with four glasses of different magnifying powers, as the objects may require. The greatest magnifiers have the least apertures. M, a round object plate, one side white and the other black, intended to render objects the more visible, by placing them, if black, upon the white, and if white, on the black side. ”

“ For a very remarkable account of the restoration of vision impaired from age, by judicious training, see Lessons in Life, by Timothy Titcomb, lesson xi. It has been much doubted whether the artists of the classic ages possessed a more perfect light than those of modern times, or whether, in executing their minute mosaics and gem engravings, they need magnifiers. ”

“ Any telescope can be made to magnify a thousand times, say, but it does not follow that you will be pleased with the result. The magnifying depends partly on the big lens or mirror about which we have been talking and partly on the "eyepiece," the little lens you put your eye to. If the object is not magnified enough you can take out this little eyepiece and put in another which magnifies more. Perhaps you have had your photograph taken and "enlarged": something of the same kind happens with a telescope, the big lens or mirror makes a little image and the eyepiece enlarges it. ”

“ Now, boys, I have let you into the secrets of my five magic glasses—the magnifying-glass, the microscope, the telescope, the photographic camera, and the spectroscope. With these and the help of chemistry you can learn to work all my spells. You can peep into the mysteries of the life of the tiniest being which moves unseen under your feet; you can peer into that vast universe, which we can never visit so long as our bodies hold us down to our little earth ”

“ A magnifying glass is most simply thought of as an additional lens to the eye. The eye has a lens by which ordinary vision is accomplished, an extra glass lens strengthens it and enables objects to be seen nearer and therefore apparently bigger. But to apply a magnifying glass to distant objects is impossible. In order to magnify distant objects, another function of lenses has also to be employed, viz., their power of forming real images, the power on which their use as burning-glasses depends: for the best focus is an image of the sun. ”

“ The total deflexion of the light, to produce the magnifying power, is equally divided between the two glasses,—the most favourable condition for diminishing that distortion which is always perceived in looking obliquely through a lens; and the field of view is greatly enlarged in proportion to the size of the eye-lens, being such as would require, to produce the same magnifying power, a single lens of the much greater semi-diameter bd, found by drawing Qb parallel to qB and erecting bd. ”

“ Little is gained by expanding the image of an object from the ten-thousandth of an inch to an inch, if there be not an equivalent revelation of hidden details. It is in this revealing quality, which I shall call magnification as distinct from amplification, that our recent lenses so brilliantly excel. It is not easy to convey to those unfamiliar with objects of extreme minuteness a correct idea of what this power is. ”

“ He comprehended the magnifying power of convex lenses and conceptualized the combination of lenses which would increase the power of vision by magnification. He realized that rays of light pass so much faster than those of sound or smell that the time is imperceptible to humans. ”

“ The study of light and vision, and the need for better methods and instruments for observing life resulted in time in the invention of the first optical device—the magnifying glass. All telescopes, microscopes, spectacles, cameras, projectors and other optical instruments have been evolved from the simple lens or magnifying glass. That lens was a special boon to the men and women who through birth, age or misfortune had poor eyesight. ”

“ We repeat again, increase your magnification always, when possible, by using higher power objectives rather than eyepieces with greater magnifying powers. Sometimes it is necessary to use a greater magnification than our most powerful objective will give us; then we must fit our most powerful eyepiece and draw out the upper part of the microscope tube—in the best instruments they are made to pull out, after the manner of the telescope. ”

“ Let us look how man tried to solve it. A magnifying lens will collect the rays from any distant object, and convey them to a point called the focus. Then suppose we put this glass in the tube of an opera-glass, or pocket spy-glass, and look through the eye-hole and the concave lens, properly adjusted, in front of it, we shall see the image of the object considerably magnified. ”

“ Material contact having proved unworkable the ideal weightless and frictionless linking was obtained by introducing a new magnetic contrivance, and this with the surprising potency of magnification from 5 to 100 million times. The mind cannot grasp the meaning of this stupendous magnification; how then could we translate it in terms which may be understood? Let us take once more our slow-footed snail, a magnification of ten million times would convert its speed to something for which there is no parallel even in modern gunnery practice. ”

“ Such an enormous magnification can not be employed in ordinary investigations on growth, for the indicating spot of light rushes on like a flash. I had, therefore, to reduce the magnification to a million times by which demonstrations of a striking character on various phenomena of growth can be given before a large audience. ”

“ If the magnification be greater than the resolving power demands, the observation is not only needlessly made more difficult, but the entrance pupil is diminished, and with it a very considerable decrease of clearness, for with an objective of a certain aperture the size of the exit pupil depends upon the magnification. ”

“ Loe Strachey's invaluable fund, the Lady Roberts fund sent me out a number of very high-class glasses of all magnifica¬tions, and after a great deal of experimenting we came to the conclusion that during all the morning hours, when the sun was facing us, we should do best for all our work with a io-power magnification, whereas, of course, when the sun went round behind us, higher-powered glasses gave better results. ”

“ We have to see the magnified picture by the light emanating from the small object, and it becomes a matter of difficulty to obtain from each point a sufficient quantity of light to bear the diffusion of a great magnifying power. ”

“ Hence, no [Pg 397] doubt, the mal occhio of the Italians, inherited from the evil eye of the ancients; hence the often almost marvelous power which some men have exercised by the mere glance of the eye. The fixed look of the magnetizer, which attracts the eye of the patient, and holds it, as it were, spell-bound, has very much the same effect, and when this look is carefully cultivated it may put others beside themselves—as was the case with Urbain Graudier, who could, at any time, cause his arms to fall into a trance by merely fixing his eyes upon them for a few minutes. ”

“ His third great discovery is the Magnetization of Light, which I should liken to the Weisshorn among mountains—high, beautiful, and alone. ”

“ A single and distinct luminous body causes stronger relief in the object than a diffused light; as may be seen by comparing one side of a landscape illuminated by the sun, and one overshadowed by clouds, and so illuminated only by the diffused light of the atmosphere. ”

“ The eye—which sees all objects reversed—retains the images for some time. This conclusion is proved by the results; because, the eye having gazed at light retains some impression of it. After looking (at it) there remain in the eye images of intense brightness, that make any less brilliant spot seem dark until the eye has lost the last trace of the impression of the stronger light. ”

“ As Attraction is stronger in small Magnets than in great ones in proportion to their Bulk, and Gravity is greater in the Surfaces of small Planets than in [Pg 352] those of great ones in proportion to their bulk, and small Bodies are agitated much more by electric attraction than great ones; so the smallness of the Rays of Light may contribute very much to the power of the Agent by which they are refracted. ”

“ You are adorable, Mademoiselle. I study your feet with the microscope and your soul with the telescope.” ”

“ The instant the atmosphere is illuminated it will be filled with an infinite number of images which are produced by the various bodies and colours assembled in it. And the eye is the target, a loadstone, of these images. ”

“ He got a good glass for six hundred dollars.
His new job gave him leisure for star-gazing.
Often he bid me come and have a look
Up the brass barrel, velvet black inside,
At a star quaking in the other end.
I recollect a night of broken clouds
And underfoot snow melted down to ice,
And melting further in the wind to mud.
Bradford and I had out the telescope.
We spread our two legs as we spread its three,
Pointed our thoughts the way we pointed it,
And standing at our leisure till the day broke,
Said some of the best things we ever said. [19]
That telescope was christened the Star-splitter,
30 Because it didn’t do a thing but split ”

“ THE BODY WHICH IS NEAREST TO THE LIGHT CASTS THE LARGEST SHADOW, AND WHY? If an object placed in front of a single light is very close to it you will see that it casts a very large shadow on the opposite wall, and the farther you remove the object from the light the smaller will the image of the shadow become. ”

“ It is impossible that the eye should project from itself, by visual rays, the visual virtue, since, as soon as it opens, that front portion [of the eye] which would give rise to this emanation would have to go forth to the object and this it could not do without time. And this being so, it could not travel so high as the sun in a month's time when the eye wanted to see it. ”

“ I ask how far away the eye can discern a non-luminous body, as, for instance, a mountain. It will be very plainly visible if the sun is behind it; and could be seen at a greater or less distance according to the sun's place in the sky. ”