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and they do not require so much manipulation; but ihey do ON PHYSICS, OR NATURAL PHILOSOPHY. not exhibit the same clearness in the lines, nor the same deli.
Cacy in the tinte,
Photography on Glass.-Photography on glass, which we owe (Continued from paga 365.)
to M. Niepce de Sant Victor, nephew to the fellow-labourer
of Daguerre, bears much analogy to photography on paper, OPTICS.
but ic gires the images more distincily and renders the details
betier. Here also two proofs are taken, the one negative, and OPTICAL INSTRUMENTS.-Continued.
the olher positive; but the first instead of being formed on Photography on Paper.-In the process of Daguerre, which paper, is on glass, covered first with a coat of albumen, or has just been described, the images are produced immedia:ely white of an egg, then with a solution of nitrate of silver, and on the metallic plates. It is not so with photography on of acetic, crystallizablc acid. The positive image is obtained paper, which comprises two distinct processes. In the first by means of the negative image, on paper impregnated with we obtain an image whose colours are reversed; that is, the chloride of sodium and nitrate
of silver. The proofs which parts which are lightest become the darkest on the paper. are thus obtained upon paper, almost equal the beauty of those and vice versa. This is the negative image. In the second which are produced on the plate. process, we avail ourselves of the first image in order to form The Magic Lantern.-The magic lantern is a small apparatus an ther, whose colours are reversed again, and are found, conse- which serves to obtain greatly magnified images of small quently, in their natural order: this is the positive image. ohjects upon a white screen in a dark chamber. It consists
To obtain the negative image, we use paper imbued with of a white iron box, in which a lamp is placed at the focus of jodide of silver, which we press, while still slightly moist, a concave reflector á, fig. 331. The rays reflected by this are between two plates of glass, in order to render its surface very received by a convergent lens B, fig. 332, which concentrates smooth. Then we put it, thus pressed, in the focus of the them towards the different figures pain!ed on a plate of glass dark chamber of Daguerre, fig. 329, in the place of the v. These figures, thus strongly illumined, are placed before the metallic plate. There, under the influence of the light, the second convergent lens c, at a distance a little greater than the iodide of silver begins to undergo decomposition, but without principal focal distance. In this position this lens produces on the image becoming apparent, the action not having been a screen at a convenient distance a real image, inveried and sufficiently prolonged. In order to render the image visible, greatly enlarged, of the objects painted on the glass. In order
the action of light.
paper is plunged into a solution of gallic acid and slightly to rectify the image, care should be taken to place the painted heated. Wherever the iodide begins to be decomposed, | glass in the lantern in such a manner that the pictures are gallate of silver is formed, which is black, and the image reversed. suddenly appears. Its shaded parts, which have not been The magic lantern was invented by father Kircher, a German subject to the action of the light, remain white, the iodide Jesuit, who died at Rome in 1680. The magnifying power of silver not having been decomposed. But as this sale of this instrument is the same as ihat of magnifying lenses, would quickly become black under the action of the light, that is, it is in the ratio of the distances from the lens c. to and would thus cause the image to vanish, the paper is then the image and the object. Consequently, if the image is 100 washed in a solution of sulphate of soda, which dissolves the times or 1,000 times more distant from the lens thun from the jodide of silver, and thus renders the image unalterable by object, the magnifying power will be 100 or 1,000. Hence
we perceive that with a lens of short focus, we can, if the This negative image once obtained serves to produce an
screen is sufficiently remote, obtain images of extreme magniindefinite number of positive ones. For that purpose, it is tude. covered with paper impregnated with chloride of silver, and
The Solar Microscope. - The solar microscope is in reality a the two sheets being pressed between two plates of glass. magic lantern, illumined by the solar rays, and is used to the whole is expnsed to the action of the light, so that the obtain greatly magnified images of objects which are extremely dark parts of the negative image cast their shade upon the minute. This instrument works in a dark chamber. Fig. paper with the chloride of silver. It then reproduces upon 333 represents it fastened to the window-shutter of the chamthis a copy of the negative image, in which the light parts are ber, and fig. 334 exhibits the internal details. replaced by the dark, and the dark by the light.
The plane mirror m, placed outside the dark chamber, There is thus a positive image. It remains to fix it, which receives the solar rays and reflects them on the convergent lens is done by washing the paper, us above described, in a solution A, and thence on a second lens e, fig 334, named the focus, of hypo-sulphate of soda.
which concentrates them at its focus. At this point is the on paper was invented by Mr. Talbot, an object whose image we wish to obtain; it is placed between Englishman, shortly after he disco ery of Daguerre. It has two glass plates o, which are introduced between two metallic been sinca improved by M. Blanquari Evrard, of Lille. 1. plates K k, that are pressed tngether by means of the spring reality it does not differ froin the process adopted by Scheele,
Tne object being then strongly illuminated, and placed except in the fixing of the image.
very near the focus of the small lens L, which is highly conProofs on paper are less expensive than those on plates, vergent, this lens forms an image ab,' inverted and greutly
magnified, on a wall or on a white screen placed at a conve- name given to a light produced by quicklime, kept white
Fiz. 335 represents the manner in which the apparatus is The direction of solar light varying continually, it is neces. arranged. In a wooden box is placed a piece of chalk c. In sary \hat the reflector placed outside the window.shutter of front is a tube A in which are two concentrical conduits, the chamber should change also, in order that the reflec'ion which do not communicate with one another, and which afford may be constantly made in a line with the axis of the micro- a passage, one for the hydrogen and the other for the oxygen, scope. The more accurate plan would be to have recoirse to both which escape into two reservoirs. At the end of the the heliostat(p. 318); but as this apparatus is very expensive, we tube DL, at D are two plano.convex lenses, m and n, arranged supply its pluce by inclining the inirror more or less by means as represented on the left of the illustration, which concenof a perpetual screw B, and a pinion, and by turning the mirror trate the light upon the ohject. This is placed between two about the lens a, which is accomplished by means of a knob a plares of glass P, which are put between two disks, of which that moves in a fixed groove, and gives the mirror a rotatory one is fixed, and the other can be moved more or less by means motion about ihe axis of the instrument.
of the four handles E, 80 that we can introduce the plate p. The solar microscope has the disadvantage of concentrating Finally, the ewo cocks 0 and u serve to regulate the flow of intense heat upon the object, which it soon alters. This is the oxygen and the hydrogen, so that the volumes of these remedied by inierposing a covering of water impregnated with two gases shall be nearly in the ratio of one of the first to alum, which arrests a part of the heat.
two of the second.
The magnifying power of the solar microscope may be The gas microscope has the advantage over the solar, inas. experimentally determined, by putting in front of the object much as it can act, whatever may be the state of the sky, a plate of glass on which are traced the divisions of distance in at any hour of the day. Electric light is sometimes em. sooo or sotou of an inch. Measuring, then, the incervals ployed with this apparatus, and gives very remarkable results. of these divisions on the image we infer the magnifying power, The Megascope. - This inserument, invented by Charles, The same process may be employed in regard to ihe gas serves to obtain magnified images of objects which are not microscope and the megascope. According to the magnifying very small, such as a statuette, a medal, or a bas-relief
. It power to be obtained, the object-glasses consist of one, twó, or has the same form as the magic lantern, only the object instead ihree lenses, all achromatic.
of being placed where the glass v is, fig. 332, occupies the
The solar microscope enables us to show a numerous assembly place of the lamp against the wall, which faces the lens . In some very curious phenoinena : for example, the circulation of the opposite angles of the box are two reflecting lainps, which the wood in the tails of tadpoles, or in the laws of frogs, the strongly illuminate the object. The ruys reflected by this
ization of salts, particularly of sal-ammondul, the come towards the lens », und forin on a discant screen ab iles in vinegar, flur puste, or stagnant water, etc. inverted image. Tu sectity it, the object must be turbed up
28 Microscope.---Tnis does not differ from the preced- when put in the apparatus. groscope, except that instead of being illuminated by The magnifying power may be varied, as in the magic lan. n, it is illurinaled by the Dranmored light. This is the tern, by mure or less approximating the object to the lens s.
Beacon Lights. -- Lenses of large dimensions present great of annular and concentric segments, each of which has a plane difficulties in their construction. They are subject, besides, surface, silucted on the same side as the plane surface of to a strong aberration of sphericity, and lose much of their the central lens, while the opposite surfaces have a curvadiaphandus quality on account of their thickness. In order ture of such a nature that the foci of the different segments
to obriate this inconvenience, lenses are constructed d échellonis, are found at the same point. The whole of these rings then
of which are formed out of a single piece of glass; bus in
larger lenses every segment is itself formed of several
In ancient times they used parabolic reflectors to throw
the large class of shopkeepers, who usually supply the young FEMALE EDUCATION.-No. III.
female operative with her gown or shawl, trust to the BY SILVERPEN. deceptive glare of gaslight to set off an inferior, if
of goods, than they would be unable to dispose of ii viewed Tende are two habits, which, generally speaking, lie at the closely by daylight, or by those of more educated taste. root of much of the female inorality of the middle and upper
A habit of gossip and tictle-tattle is an intensely low and classes of society, and at much of the female immorality of vulyar thing. To prate and be curious about other people's the operative masses. I allude to the fact, that, on the one attairs is so mean and paltry as to merit the heartiest con. hand, the young girl or young woman never, under any possible tempt of any one ordinarily intelligent, or possessing any circumstances, enters a gin-shop or public-house, or is our generosity of character; and I do not care if gossip be the alone in the streets after night all; whilst on the other hand, habit of a duchess or a maid-servant, a mill hand or one many young women more or less frequent these places, and calling herself a “gentlewoman," it is equally the mark of a carry on their courtships and gossiping acquaintanceships at mean spirit and of low breeding. Not that I ignore interest, lane-ends, and court ends, and in the streets, after the erening and sympathy, and love. Let there be more of these, let hur cloned around. Now, whilst many of our most important every channel of human life till to overflowing, for there is social questions can only be solved by the descent, as it were, need; but those who would give proof of education, who aim of our higher and middle classes to a plainer, less ostentatious at the moral advance that social interests require, can have mode of life, so it is equally true that the same questions no time, and should have no taste, for what is only fitted, to need a visible ascent through self-improvement and education say the least, for the weak and triping. What in the world of the moralities of the operative masses. And nothing would can it matter to one young woman how many gowns and how assist this great need further than that young women of the many sweethearts another has ? or to the Browns what the working classes should repudiate these habits with all the Smiths next door hare for dinner, or whether they are earnestnesa choy can. Wnue is immoral in the sight of, and I prudent or imprudent in doing such and such a thing? Be. distastelul to, one class, must sure y be so for another; for 1, sides, to say nothing of the waste of time, of the consequent can neither believe in, nor understand, any natural inequality neglect of duties, and of the in rariability of a love of gossip in the morals of progressire bunan creatures; and as I being connected with other bad habits, ii begets more or less earnestly wish to give good counsel, let this habit of entering a vicious love of scandal. And think what this scandal often publiu-divuses, or of considering th-on as filling places of is! Think that it is the detamation of one woman's character amusement, be for ever set aside by those young women who by another, and often for no worse cause than "devil's envy; can understand and really value in all their worth a pure that the one defanied is purer, prettier, kinder-hearted, or is reputation and a progress in refinement and morals." or more a favourite. The whole round of human wrong-which course I do not here include errands, or small matcers of is unfortunately a pretty wide one-has no more Aagrant evil business, which may occasionally take a young woman within than this, of one woman speaking dispitefully of another, of & public-house, as into a shop or other dwelling, for I un putting the worst construction upon every action of judgment doubtedly address myself to many unconnected with the by mere hearsay. But the pure in act, the kindly in heart
, temperance question, viewed strictly in its relation to total the generous in spirit, will always speak and judge mercifully, abstinence; what I mean here is, the habitual or occasional especially of their own sex; and I know of no more lovely, frequenting publie-houses and gin-shops as places of refresh. more in the best senses religious, no more nobly feminine ment and amusement. But in neither sense are they worthy habit, than that women, young women especially, should of the name.
speak and think of their own sex with kindness and mercy, As to courtships and acquaintanceships carried on in the Let the vice of evil-speaking and scandal be left to the painted streets after nigherall, they are not well. Even as to habits, dowagers of the higher classes, to the ill-conditioned spinsters generally speaking, they are out of place with womanly self and vulgar mammas of the middle class, to the low, coarse respect, for though protected by a lover, much must be heard women of the working classes ; but let the young women of and seen by a young woman that it were best she was ignorant the operative masses, the sisters, the future wives of thought'ul of. I know allowance must be made for those whose work working men, give proof of a genial advance in the needed confines them through the day, and who may have no cheerful, direction of moral habits and moral duties, by avoiding this cleanly home to receive, or kind parents to invite a lover; yet low.bred vice of scandal; this vice of lane-ends, street-ends, I feel sure as a rule tnat young women of the operative classes and court ways; this vice which gentlemen who write Blue are so unaware of the immense intellectual advance of many Books for parliament deplure as one of the signs of a low conof the young men amongst whom they naturally look for dition of the people. admirers and husbands, as scarcely to bring titting habits of Nor can I pass from this question without a word as to reserve and womanly delicacy to bear upon the general face of habit worthy of the utmost condemnation by all good and their intercourse. But let this matter be better understood. earnest young women. I allude to the love of impure converMen of the operative classes, men working in shops and sation, either as listener or speaker. Such conversation may factories in Birmingham, in mills and warehouses in Mun. be said to be in jest, or in fun; its purpose may be hidden like chester, in milis ia Lteds, Huddersüeld, and Derby, are an evil face with a fair mask, by words expressing one thing making an immeare advance in intelligence, in clear far-seeing nut really meaning another ; but it is not ihe less impure for though', in those sell-restraints that honour body and soul: that; and if such "jokes' are habitually indulged in of and would, I firmly believe, reverence and respect any advance listened to, the end may prove terrible in its earnestness ; young women might make in modest circumspection. Many because I firmly believe that no individual can indulge in any such men are ultimately drawn down to the level of a woman's kind of gross conversation without acquiring a proportionate coarseness and low habits; but there are others, and the depravity of character. I do not wish it to be inought for a number must necessarily increase as they make intellectual momentihat I am writing a series of moral sermons to the advance, who would rather remain single than trust their own working classes ; I am only speaking earnestly from my heart, and children's future welfare to those who lightly pacethe streets what my experience of life and my knowlede of books have at pightfall, even though with themselves, or who can find taught me, and to declare with pride, which nothing could charms in the low convivialny of the beer or gin-shop. I shake or bow, that in all which is most lovely in the feminine only as a matter of prudence, it therefore behoves young character Gud made all women akin; and be her bears and wuinen of the operative classes to shape their habits and conversation but pure, and her efforts after self-improvement behavivur in accordance with the moral and intellectual earnest, the poorest mill-gul that Manchester may hold, stands Advance of those amongst whom they look for husbands. Il side by side, in all the best moral aspect of human life, with may be said that those wno have little or no time through the the highest, purest lady in the land. It makes me proud to duy, are necessarily led into the streets by night by their need think and know this; let it make those rightly proud who at visiting shops for ino purchase of apparel, and other things will read what I now write : Iee them strive for this pura #sionally such
a wanit may arisu: but, generally speakug, heart, these pure lips; let them avoid as companions and *tion of the noon-uny hour would be better spared for friends all who indulge in gross habits or gross conversation, Yes y this sort, particularly when it is rocollected that whether at home, in ide null or sbop, or in the street ; and it
carried on in their presence, let them strive to suppress it, or, to her hande strengthened every root. How was she erer to
and baring her bosom, with loud laughter, and eyes dry 18
“ O Thou great,
of the most sinful of ihy crearures! Oh! save my soul, lest LESSONS IN READING AND ELOCUTION. it perish, even for thy own name's sake! O ihou, who diedst
to save sinners, have mercy upon me!! No. XXI.
Cliffs, chasms, blocks of stone, and the skeletons of old
trees, --far-far down, and dwindled into specks, a thousand CHILD CARRIED AWAY BY AN EAGLE.
creatures of her own kind, stationary, or running to and fro! Tas great Golden Eagle, the pride and the pest of the parish, Was that the sound of the waterfall
, or the faint roar of stooped down, and an ay with something in his talons. One voices? Is that her native strath?--and that tuft of trees, single sudden female shriek, -and then shouts and outcries, as does it contain the hur in which stands the cradle of her if a church spire had tumbled down on a congregation at a sacra- child ? Never more shall it be rocked by her foot! Here ment! "Hinnah Limond's bairn! Hannah Lamond's hairn!" | must she die,—and when her breast is exhausted, her baby was the loud fast-spreading cry. “The engle's ta'en off Hannah too!
And those horrid beaks, and eyes, and talons, and Lumend's bairn!" and many hundred feet were in another wings, will return; and her child will be devoured at last, instant hurrying towards the mountain. Two miles, of hill
, even within the dead bosom that can protect it no longer. aid dale, and copse, and shinyle, and many intersecting
Where all this while was Mark Steuart, the sailor! Half
dizzy, and his heart sick ;-and he who had so ofien retfed the
ony puir human means? We have no power but in prayer!" She looked around, expecting to see an angel ;—but nothing
Hannah Lamond had all this while been sitting on a rock, sympathy of her soui with ihe inanimate object, watched its
, on a small platform.
, they were row swallowed up in the agony of eye. open her eyes, she slid down the shelving rocks, and found
its fall. There the shingle rattled down the screes, and she
rho sees her bahy, whose warın mouth had just left her her head and Iroking down, lo! the whole population of the
kirk, along with all the congregation. An unseen hand