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of the lens
oblique annual course he would soon learn pearances with which we become acto identify the variety and succession of the quainted by its means. seasons. As population increased, the cul- The glasses employed for optical purtivators of the soil sought and obtained poses are denominated lenses, and are some knowledge of the celestial motions, formed by the process of grinding into the that they might with certainty determine following figures, both the seed time and the harvest.” In pastoral life also, such knowledge would be found essential to regulate the migrations Axis of the shepherd; and history informs us that the Chaldeans, enjoying the leisure of Figure 1. Represents a prism as viewed such a life, with the facilities of the spa- end-wise, and is in shape like an equilateral cious and unclouded horizon of their native triangle. plains, were among the foremost in observ- 2. A plane glass, which is perfectly fat ing and recording the more striking of the on both sides, and of equal thickness in all celestial phenomena.
It has been said, that " an undevout as- 3. A spherical lens, or perfect globe, all tronomer is mad." And if our remote an- the points on its surface being equally dis cestors of the earliest ages could find, " in tant from its centre. looking through nature up to nature's God,” 4. A double convex lens, which is a sotheir hearts warmed, and their devotional lid piece of glass, having two convex sphefeelings increased with every new accession rical surfaces, each in shape like the outside to their knowledge, which must necessarily of a watch-glass. have been acquired with unassisted vision, 5. A plano convex lens, which is ftat on what must have been the feelings of asto- one side and convex on the other. nished and pious excitement, in him who 6. A double concave leps, which is confirst directed that wondrous instrument, the cave (or hollowed out like the inside of a telescope, to the starry heavens! It imparts watch-glass) on both sides, and may be a range of ken more than possessed equally or unequally concave. oy eagles' eyes, and exhibits to our finite
7. A plano concave lens, which is flat powers a magnificent view of the immensi- on one side and concave on the other. ty, the beauty, and the harmony of that 8. A meniscus, which is a lens, one of universe, of which the world we inhabit whose surfaces is convex, and the other forms so insignificant a member. And ex
As the convexity exceeds the perience teaches us, that the boundary of concavity, it may be regarded as a convex our vision thus extended, lies nowhere but lens. in the imperfection of our telescopes; for 9. A concavo-convex lens, which also who can say how far the universe extends, has one of its surfaces convex and the other or where are the limits of it?-where the concave, but as the concavity exceeds the Creator stayed “ his rapid wheels,” or convexity, it may be regarded as a concave where he “'fixed his golden compasses ?” | lens. That man is little to be envied (be his ac- An imaginary line passing through the quirements or possessions what they may) centres of the curved surfaces, and perpenwho can with a cold indifference view these dicular to the plane surfaces of lenses, is wondrous scenes ; more especially if, un called their axis: thus, in the figure below, derstanding the nature and constancy of the let A B represent a double convex glass, the celestial motions, he cannot both feel and surfaces being segments of the two equal acknowledge that “the heavens declare the circles, then a line passing through the two glory of God, and the firmament showeth centres cc of the circles would be called the his handywork."
axis of the lens; the same holds good of all It is our present object to bring before the other lenses, as shown in our former our readers a familiar account of the figure. principles of that instrument by which our faculty of vision is so much assisted ; and after explaining the shape and arrangement of those glasses which constitute the telescope, and in that form produce such remarkable effects, we purpose introducing, by way of illustration, a short descriptive account of those celestial bodies and ap- The peculiar properties of such of these
lenses as are more immediately connected, would distinctly see a perfect image of the with our subject, in the refraction of the object c formed on the ground glass, and rays of light, (that is, bending the rays, or by steadily keeping the eye in the same causing them to change their course,) we position, the ground glass may be removed, shall now explain.
and the image will appear in the same spot It must be premised that rays of light suspended in the air. What an astonishproceed in straight lines, but are diverted ing effect is thus produced by a convex from their course, or refracted, as it is lens ! the object supposed to be very remote termed, when they pass from one medium at c, is suddenly transported as it were to to another, as shown by the following fami- h, from which the eye must undoubtedly liar instance:-A straight stick when partly receive a very different impression from immersed in water, appears to be bent up what it would do if, withdrawing the lens, wards, at the surface of the fluid ; which is it were to view the object c immediately. an optical deception, and arises from the The focus h, where the image of the distant rays of light being bent or changed in the object is formed, has a remarkable property; direction of their course, as soon as they and we shall digress in this place to speak reach the surface of the water, in passing of it. Suppose the sun to be the object at out of it. The density of the water being c, the rays which fall on the lens are all so much greater than that of the air, is the collected at h, and being endowed with the cause of this great refraction, and produces quality of heating, it is natural that the the apparent distortion of the stick.
concourse of so many rays at one point Let us now consider the refraction of should produce a degree of heat, capable rays by a convex lens, which suppose to be of setting on fire any combustible matter A B in the figure below, whose axis is in that might be placed there; hence a conthe direction of the straight line c D, and let vex lens is commonly denominated a burn
ing glass. The image formed at the focus h will be an inverted image of the object C, as will readily be understood from the following figure.
there be an object at c, which imagine to be at a great distance from the lens. This object diffusing rays of light in all directions, some of them will pass through the Suppose the man at A was observed lens A B, as ce, cf, and cg, of which through a lens at B, the rays which fall ce in the direction of the axis of the lens upon the lens will, as before stated, be rewill suffer no refraction, but continue the fracted, and form an image on the other same rectilineal course towards D. The side. We before had occasion to remark, other two rays cf and cg (as well as all in- that those rays which pass through thé termediate rays) in passing through the lens centre of the lens in the direction of its nearer the edge, will be so refracted both axis, suffer no refraction; the same is true at entering and departing, that they will of all rays which pass through the centre, afterward meet the axis, as at h the focus whether they fall upon the surface in the of the glass, where they will (if not inter- direction of the axis or otherwise, because cepted) cross each other's path, and con- the opposite surfaces in the direction of tinue in the same straight lines B i and a k. such rays are parallel to each other. ThereThe rays of light cf and cg would, if no fore the image of the man's head must be lens had interfered, have continued onward formed in the line a b, which is the direcin the direction they first had; but under- tion of the ray passing from the crown of going refraction at A B, they are compelled his head through the centre of the glass, to change their directions, and proceed as if and that of his feet in the line c d, forming they had emanated from the point h, where an inverted image of the man. an image of the object c would be formed. The image d b may now be considered a If a piece of ground glass, transparent new object, and by placing another lens at paper, or a plate of glass having one sur- c, an additional image of this image would face covered with a dried film of skimmed be formed at e f, exactly in the same man. milk, be held up at h, a person looking at ner as if d b was a real object. But since it from D a few inches behind the glass, the new image must be inverted with
respect to db, it will be an erect image of the One of the most frequent ornaments of a object or man at A; so that by using one cottager's window is a geranium, and of or more lenses, direct or inverted images those flowers which variegate the borders may be obtained at pleasure.
of our domestic enclosures, some of the The reader may now form an idea of the brilliant specimens of this sort form not the method by which opticians cause the tele- least considerable portion. Among the orscopes intended to view terrestial objects, dinary points of resemblance by which the to show them erect or in their natural posi- members of this family are bound together, tion. But those constructed for astrono- as by the common ties of affinity, we may mical purposes show them inverted; to the notice, in the first place, the constant astronomer this apparent inversion being of presence of ten stamens, with half that no consequence, and as fewer glasses are number of petals, that is, of coloured placed in his telescopes, the objects appear parts wbich are unconnected with each brighter, (which is of greater importance to other. These stamens are united at their him,) the rays having less dense medium base by the mutual junction of the flat to pass through; for in every refraction some tened filaments. The style or central pilrays must necessarily be lost. And as the lar is usually prominent, and is ultimately brightness of the object depends upon the prolonged into a beaked point, like the quantity of rays which reach the eye, it is bill of a bird, or specially that of a crane, evident that the larger the lens, the more whence the plants have long since obrays it will receive and transmit; conse- tained the name of geranium, or cranesquently a telescope of large aperture must bill. The style terminates in five stigbe the most desirable, especially for astro- mata or rosy points, which descend down nomical purposes.
along the outside of this central pillar, and, at the base, are each of them
enlarged into a seed-vessel, containing SCRIPTURE EXPLANATIONS.-No. XXXII. one seed. Hence, at the base, we find a “He speakech with his feet, he teacheth with his circle consisting of five distinct protubefingers.”-Prov. vi. 13.
rances; these finally separate, and are It should be remembered, that when lifted up out of their original situation by people are in their houses, they do not the desceuding threads, which we have wear sandals; consequently their feet and just described, as respectively a contitoes are exposed. When guests wish to nuation of the stigmata, or rosy points. speak with each other, so as not to be ob- This operation of lifting up the seeds with served by the host, they convey their mean- their cases, is performed by the twisting ing by the feet and toes. Does a person of the threads, either in a spiral direcwish to leave a room in company with tion, like a screw, or by simply curling up another, he lifts up one of his feet; and like a lady's ringlets. The effect of these should the other refuse, he also lifts up a curious processes, is to place the seed in foot, and then suddenly puts it down on a favourable position for being wafted to the ground.
a distance, by that general medium of “ He teacheth with his fingers.” When distribution, the wind. If we look with merchants wish to make a bargain in the an eye that covets instruction, at the presence of others, without making known flower-stem just below the calyx, we shall their terms, they sit on the ground, have perceive, in some instances, a spur, and a piece of cloth thrown over the lap, and in all others, an enlargement on the upper then put each a hand under, and thus side, which is hollow, and is extended speak with the fingers! When the brah various lengths down the flower-stem, so mins convey religious mysteries to their as to afford an auxiliary mark for specific disciples, they teach with their fingers, distinction. having the hands concealed in the folds of This whole family were once compretheir robes.—Roberts.
hended under one genus, geranium; but of late, it has been found more convenient for the purposes of study, to distribute the species known at present, into five
genera, three of which may be distinWe are just going to take a passing guished, and exemplified in the following view of a family of plants not less fami- manner. liar to us than they are deserving of a Geranium. All the stamens bearing more intimate acquaintance than it is anthers when the bud first opens, with a co ninonly their lot to obtain among us. little gland at the base of each of the
THE HUMAN COMPLEXION.
longer stamens. Seeds lifted by the equipment upon the leaf. But as vacoiling up of their supporters, which, in rieties are every day increasing, it would this position, resemble a spring. This not suit our limits to give an enumeragenus will be exemplified by looking at tion. Some shown us the other day, of the jagged cranesbill, (geranium dissec- peculiar splendour, bore the names of tum,) very common by the road-sides, or individuals now living, distinguished buth by reference to the herb robert, (G. ro- in military and civil stations. bertianum,) which is very often seen on ditch-banks under hedges. Its general resemblance to the geraniums in our pots, its pink red flowers, and beaked fruit, Bishop Heber observes, “I thought it added to the strong disagreeable smell of remarkable, that though most of the male Inits foliage, will not fail to denote it to dian deities are of a deep brown colour, like the curious eye, while a close examina- the natives of the country, the females are no tion of its peculiarities will afford an less red and white than our porcelain beauagreeable lesson of botanical instruction. ties, as exhibited in England. But it is
Erodium. In this genus we miss the evident, from the expressions of most of spur or tube in the flower-stalk. Of the the Indians themselves, from the style of ten stamens, five bear anthers, and five their amatory poetry, and other circumare barren, at the base of which latter stances, that they consider fairness as a part five, we meet with five glands correspond- of beauty, and a proof of noble blood. ing to them in number. But what is They do not like to be called black, and most likely to engage our attention is, the though the Abyssinians, who are sometimes screw or worm-like twisting of the sup- met with in the country, are very little porters, to raise the seed from its lodging darker than they are themselves, yet their below.
jest-books are full of taunts on their charAn example may be sought for in the coal complexion. Much of this has prohemlock cranesbill, (erodium cicutarium.) bably arisen from their having been so long This plant may be distinguished by its subjected to the Moguls, and other condivided wing-like leaf, its red flowers, querors, originally from northern climates. which have the general likeness of the India, too, has been always, and long before geraniums, and its strong smell: it is very the Europeans came hither, a favourite common by road-sides. There will be theatre for adventurers from Persia, Greece, no difficulty, either in finding or in re- Tartary, and Arabia, all white men, and cognising the hemlock-leaved cranesbill, all in their turn possessing themselves of since the similitude of the individuals is wealth and power. These circumstances so striking, that to know one, is to know
must have greatly contributed to make a all, as far as recognition is concerned. fair complexion fashionable. It is remark
Pelargonium. Upper division of the able, however, to observe how surely all calyx, running into a tube, which ap- these classes of men, in a few generations, pears upon the flower-stalk, descending even without any intermarrying with the in a direction between the upper pair of Hindoos, assume the deep olive tint, little petals, which form a pair differing in less dark than a negro, which seems natushape from the rest. The fertile stamens ral to the climate. The Portuguese natives vary from four leaves to seven, while the form unions among themselves alone, or, supporters are beaded on the inner side, if they can, with other Europeans, and yet and twist spirally, to raise the seed from have they, during a 300 years' residence, its lodging. Examples are to be found become as black as Caffres. Surely this among all the garden varieties, which are goes far to disprove the assertion, that clioriginally natives of the Cape of Good mate alone is insufficient to account for the Hope, but by the cultivator's skill they difference between the European and the have been improved and multiplied by negro. It is true, that in the negro are crossing, so that, oftentimes, in our green- other peculiarities to which the European houses and conservatories, few plants colonists show no approximation, and which make a more beautiful and conspicuous undoubtedly do not appear to follow so nafigure.
turally from the climate, as that swarthiness One of the oldest, and not the least of complexion which is the sole distinction attractive and beautiful, is the horse- between the Hindoo and the European. shoe geranium and its varieties, which But if heat produces one change, other pebear the figure of that part of a horse's culiarities of climate may produce other
and additional changes; and when such in India where, only a few years ago, the peculiarities have 3000 or 4000 years to most revolting barbarities were practised, operate in, it is not easy to fix any limits " I was mentioning to bishop Heber, how to their power. I am inclined, after all, forcibly it had struck me, during the serto suspect that our European vanity leads vice, in that hall, where, a few years us astray in supposing that our own is the ago, the most savage tyrant received bis primitive complexion, which I should ra- miserable subjects, a christian prelate was ther suppose was that of the Indian, half- now administering the solemn ordinances way between the two extremes, and per- of our religion. He leaned his head on haps the most agreeable to the eye and the his hand, and burst into tears. • How instinct of the majority of the human race. wonderful,' said he, ‘ is the providence A colder climate, and a constant use of of God, in the economy of his church! clothes, may have blanched the skin as Never was any people entrusted with effectually as a burning sun or nakedness such a power of doing good as England may have tanned it. Thus, while hardship, now is! What a fearful responsibility additional exposure, a greater degree of rests on the government and its minisheat, and other circumstances with which ters; on the nation and all its children ; we are unacquainted, may have deteriorated and, above all, on our church and its the Hindoo into a negro, opposite courses rulers !! Such were the remarks made may have changed him into the progreso in the palace of the deposed Emperor of sively lighter tints of the Chinese, the Per- Candy on this memorable morning." sian, and the European."
EXPENSES AT ETON IN THE
FORGETFULNESS.- A wretch that is con
demned to die to-morrow cannot forget it, Of the expenses incurred for school and yet poor sinners, that continually are boys at Eton, early in the reign of Elizabeth, uncertain to live an hour, and certain we find some curious particulars in a ma
speedily to see the majesty of the Lord, nuscript of the time. The boys were sons
to their inconceivable joy or terror, as sure of Sir William Cavendish, of Chatsworth, these things for which they have their me,
as they now live upon earth, can forget and the entries are worth notice, as showing the manners of those days. Among the drown the matters of this world, as the re
mory, and which one would think should items, a breast of roast mutton is charged port of a cannon doth a whisper, or as the ten-pence; a small chicken, four-pence; a week's board, five shillings each, besides derful stupidity of an unregenerate soul! oh
sun obscures a poor glow-worm. Oh wonthe wood burned in their chamber; to an old woman for sweeping and cleaning the wonderful folly and distractedness of the chamber, two-pence; mending a shoe, one
ungodly, that ever men can forget I say penny; three candles, nine-pence ; a book, again, that they can forget éternal joy, eter
and the eternal God, and the Æsop's Fables, four-pence; two pair of shoes, sixteen-pence; two bunches of wax abode ! when they stand even at the door,
place of their eternal and unchangeable lights, one penny; the sum total of the and there is but the thin veil of flesh be-payments, including board, paid to the bursers of Eton College, living expenses for
tween them and that amazing sight, that the two boys and their man, clothes, books, eternal gulf, and they are daily dying and washing, &c., amount to twelve pounds,
stepping in !-Baxter. twelve shillings, and seven-pence.
The expense of a scholar at the university in 1514 was but five pounds annually, afford
The BELIEVER. - A believer's heel ing as much accommodation as would now may be bruised, but his vital parts are cost sixty pounds, though the accommoda. out of reach, Zech. ii. 8, 1 John v. 18.tion would be far short of that now cus
Cole. tomary at Eton.--Domestic Life in England.
JOHN DAVIS, 56, Paternoster Row, London. ENGLAND'S RESPONSIBILITY.
Price fd. each, or in Monthly Parts, containing Five Mr. Robinson remarks, adverting tothe
Numbers in a Cover, 3d. fact of a confirmation being held in a place W. TYLER, Printer, Bolt-court, Fleet-street.