From the Riverside Magazine. Many persons suppose that the two pictures which form a stereoscopic view are just alike, and that it is solely the stereoscopic instrument which produces the peculiar effect of distance and perspective in the figures represented. This is a mistake. The two pictures upon one slide are, in reality, different from each other; and the peculiar effect depends upon this difference. Two pictures precisely alike, and placed side by side, will not be a stereoscopic view. The difference is very slight, and a casual observer may compare the two without discerning it. And even one who is informed that there is a difference may examine a number of slides before he will detect what it is, for in some views it is much more obvious than in others; but the difference exists in all, and is essential to constitute a stereoscopic picture. If you shut one eye, and look with the other only, you will see less distinctly than with both. But besides the lack of distinctness, you will find that there is another singular difference between looking with one eye and with two. With one eye you cannot accurately judge of distances. If you ask some person to put forth his hand, and to shut one eye, and you then bring some object, such as a book, at one side of his hand, but at a little distance from it, and ask him to touch the book, he will move his finger in the direction in which the book seems to be, but very likely he will not touch it at all; for with one eye he cannot judge whether you have brought it within his reach or hold it just beyond his reach. The same thing is seen by placing a closed penknife a quarter of the edge of the table, and then with one eye shut taking three steps toward the table, the distance having been previously measured, so as to bring the person at arms' length away, and attempting with the forefinger to strike the knife, which is on a line with the finger. In almost every trial the finger will fall short of striking the knife. There is another difference to be noticed be sides that of distance. Put a wafer on the glass pane of the window, and then look out with one eye and observe what object in the landscape is hidden by the wafer. Then, without moving the head, close that eye and open the other. The wafer will no longer hide the same object, but it will appear to have moved toward one side, and it now hides something else. If, then, still keeping the head in the same position, you look with both eyes open, you will see both the objects that were before concealed, but at the same time you will seem to see two wafers, one against each of these objects. While the sight is fixed upon the landscape beyond, the wafer seems double; but if you fix your sight on the wafer, you may be conscious of a double image of the objects beyond. If a wafer is not at hand, the end of the finger placed against the glass will answer the purpose. The same effect may be produced very clearly by holding up one finger to look at, and with the other hand holding up, at a distance beyond it, a pencil or any such object, and comparing the vision received by one eye alone with that received by the other. Then, with both eyes open, observe that if both eyes are fixed on the finger two pencils are seen, and if both are fixed on the pencil two fingers are seen. While looking thus with both eyes, if the pencil be removed to a greater distance, the two images of the finger will appear to open, or remove from each other; or, if the sight is at the time fixed upon the finger, the two images of the pencil will appear to open or remove from each other. Looking out of a door or window, first with one eye and then quickly with the other, presents to view two different pictures of what is beyond; and what we see when we look with both eyes contains all that is visible in either view. At whatever we look, in ordinary visions, these double images are produced. And although we are not usually conscious of the process, it is by no means of these double images that we are able to estimate distances. If we had not two eyes we could not have these double images. Each eye forms upon its own retina a different picture; and as the eyes are not one above the other, but on the same horizontal plane, things which come precisely in range with each other in the view of one eye, cannot be precisely in range with each other in the view of the other eye. It is for this reason that the marksman shuts one eye same when he lays a course with the compass; when he takes aim; the surveyor does the and the carpenter, when he sights a straight edge. While one eye cannot measure distances, two eyes cannot take a range. Therefore we know that not only two separate pictures are taken by the eyes, in ordinary vision, but these pictures are unlike. They are of the same size, and embrace the same general objects, but each is from a different point of view, depending on the distance from the pupil of one eye to that of the other; and each therefore is with a different perspective. Look now at one of the slides for the stereo scope, and it will be seen that the two pictures upon it differ in the same way. A view that presents some tall object in the foreground, such as a tower, or the stem of a tree, and some other objects at a distance behind it, is the best for this purpose. The things which the tree or tower conceals in one picture will be shown or partly shown in the other, the tree or tower seeming to be slightly moved, just as the wafer on the window-pane appeared. Swiss say the glacier purifies itself. For, strange as it seems, the glacier does not suffer either block or grain of sand within its clear, The camera with which ordinary photographs are taken is like the eye. It is, in fact, an imi-transparent masses, and, though covered for tation of the eye. The round hole, or tube, in front, contains the lens, which is like the cornea or surface of the eyeball, and the crystalline lens which is contained within it; and the brass cap, which shuts over the tube, is like the eyelids, to keep the dust out. There is a round disk, with a hole in its centre, which fits into the tube; this is called the diaphragm, or stop. This is like the iris with the pupil, which enlarges or contracts according to the degree of light. The photographer cannot make the aperture in his brass disk or diaphragm expand or contract, and therefore he usually provides several, with apertures of different sizes, and changes them from time to time, as he may need. The plate of glass, which he brings out of his dark room, in a thin black case, and slips down into the camera when the sittter is ready to have the picture taken, is like the retina or membrane in the back part of the eye. It is upon this that the picture is taken; and as in the eye, so in the camera, the picture is taken upside down. The ordinary camera thus resembles one eye, and the pictures taken with it resembles the vision which we get when we look with one eye. The camera with which stereoscopic pictures are made is a double camera, and resembles a forehead with two eyes in it. It makes two pictures at the same time, which differ from each other as the image received by one eye differs from that received by the other. And it is because they differ that they present, when seen together as one, the appearances of distance and perspective, as if we were looking at real objects with both eyes. The stereoscope itself is a peculiar pair of spectacles, to help us see the two pictures as one, by looking at each one with the corresponding eye. A. A. HOW THE GLACIERS PURIFY THEMSELVES. They have, however, one mode of travel unlike all other kinds of locomotion, and so mysterious that human science has not yet fathomed its nature. Large masses of rock, of truly gigantic dimensions, when by accident they fall into the deep crevices of these glaciers, return with quiet irresistible energy to the surface, moving slowly, steadily upward. Thus, not unfrequently, vast pyramids or stately pillars of ice, broken loose from the mother glacier, are seen standing in isolated grandeur, and crowned with huge masses of stone. After a while, the strange forms change and melt, the rock sinks deeper and deeper, until at last it is lost to sight, deeply buried in snow and ice. Yet, after a time, it reappears above, and the miles with millions of crumbling stones, with heaps of foliage, and debris of every kind, at the foot of the mountain it is so clear and pure that even the microscope fails to discern the presence of foreign bodies in its limpid waters. What is equally amazing is, that while all weighty objects, leaves, insects, dead bodies, stones, or gravel, sink alike into the cold bed, the organic parts decay quickly in the frozen, rigid mass, but the inorganic parts are thrown up again. Years ago, a horse fell into one of these glaciers; it sank, making its outline distinctly, until it was seen no more. A year afterward the clean, white skeleton projected from the top through the clear ice. In the middle of the sixteenth century, there was a succession of long winters, during which immense masses of snow fell, and increased the glaciers so much that they travelled faster and lower than usual, and in their course overwhelmed a little chapel at the foot of the Grindelwald. All was covered mountains high with snow and ice, and so remained for years, buried in ghastly silence. Buu, lo! all of a sudden there appeared a black, ungainly mass, high up on the glittering field it was the chapel bell! Pious hands saved it, carried it to a neighboring town, and now the long-buried bell rings merrily, Sabbath after Sabbath.-N. Y. Independent. THE BIRD OF TWO SONGS. I was standing in the garden with a stranger one cloudy, chilly, unsummer like afternoon in June. Near us was a large clump of lilac bushes, into which we saw a bird of a dingy, faded black color fly. Presently she broke out into what, perhaps, she called a song; but it was, in reality, just like the flat squalling of an old cat. "Yaah! yaah!" she continued to cry. Pray," said the stranger, "what bird is that making such a horrible noise?" "That, sir, is the cat bird." "I should think so, and a burnt cat, too! I thought it was homely enough to the eye, but the color is nothing to this screech." "I can't say much at present to defend the poor bird, for looks and voice are against her. But I am confident you will think better of her ere long." The next morning I found my friend standing in the piazza, listening to the notes of a bird in a thick sugar-maple near by. The song was that of a mocking- bird, not so wonderful as the notes of the real mocking-bird, nor even so sweet as that of the thrush, yet they were round and full, and often exquisite. She seemed to repeat the note of every bird with which she was acquainted,-robin, sparrow, oriole, and the | for every description of sores and cuts or "That, sir, is our cat-bird." "You must be making fun of me. You don't pretend to say that the homely squalling bird we heard yesterday, and this singer, are the same?" "I do truly, and to convince you I will throw a stone into the tree and drive her out, and you shall see it is the same bird." With that I threw the stone, and out popped Mrs. Cat-bird, making directly for the lilacs, where she began again to scream, Yaah! yaah!" 66 The gentleman looked on in amazement. "This bird," said I, "is very much like some people. In those lilacs she has her nest, and that is her home; but there she never utters a pleasant note. I should think her husband would avoid her, and her little ones tremble at the sound of her voice. But when she gets away from home, up in the lofty tree, you see how agreeable she can be. I know many people just like her. When away from home, they are fall of smiles and gentle ways, and they seem among the most agreeable people in the world. But see them at home! and the cat-bird's notes are theirs. They contrive to make home just as unpleasant as possible-to themselves, to their children, and to every body that happens to see them at home.- Western Christian Advo even asserted now, that for flesh wounds it is a prompt and perfect cure or prophylactic against erysipelas, that dread monster that haunted the hospitals of both sides so faithfully during our recent war, and that proved the death of so many brave men. It is to be hoped that this will be thoroughly investigated, and, if it should prove effectual in this terrible disease, that the fact may be generally known. It is already known that by applying either crude or refined petroleum to flesh cuts or other wounds, that all offensive suppuration is checked or avoided, and that the fissure speedily heals, apparently by "first intention." Petroleum in a crude state is also of value for painting purposes. There are two sorts of this article, the heavy or fixed oil, usually in common use for lubricating purposes, and the light or volatile oil used for illuminating. The latter only is used for painting, and for outside work is superior to any other oil, as well as for "priming," or first coating, or stopping, inside work. The chief value of the oil for painting seems to be in the residuum, the black pitchy substance left after distilling the refined oil from it. This residuum, when spread out as paint, forms a thin surface, protecting the work from the air. To prepare the oil for paiuting, it ought to be about half distilled, thickening up what is left, or adding about a pound of the residuum to a gallon of common crude volatile oil. To do this I have melted the residuum carefully in a pot over a stove, (care being taken against fire), gradually adding thin crude oil to it. The mixture is not very perfect, and the thick matter settles when cold, but it can be shaken or stirred up when about to be used. The color of course is nearly Desponding as men usually are, too apt to black, but not much more so than the preparalook only to the troubles they have to contendtion known as boiled linseed oil, which is conagainst in this world, we must all admit that sidered the best of all paint oils. the Great Giver of all Good seems to be constantly striving to bring those made after His image closer to Him, and add to their comfort while in this world. What beneficent discov. eries has He vouchsafed to us within a few short years. The railway has supplanted the common road; the steamer, the sloop and barge; the reaper, the scythe; the sewing machine, the needle; petroleum, the dingy, dirty, old tallow candle. Truly of all modern discoveries, petroleum is certainly not least valuable, and here I propose to enumerate a few of its most valuable economic properties. cate. From The Cultivator and Country Gentleman. Of course this preparation is best for all rough outside work, exposed to the elements. It is superior for wagons, plows and all farmers' implements, preserving them effectually. For wood work, the best pigment I have used, as well as the cheapest, is the common hydraulic cement, or water lime, costing about two or three dollars a barrel. It makes a cool, pleasant grey or neutral tint, entirely different from the brown and chocolate colored earths, as well as much cheaper than they are. It must of course be ground with the oil in a paint mill, as all other paints should be. As a medicine for both man and beast, it is At the present time petroleum thus prepared certainly without an equal. For rheumatic for painting ought to be retailed everywherǝ complaints, lumbago, and all pains and aches, for not more than seventy-five cents a gallon. used externally, it gives almost instantaneous As this is half the price of linseed oil, as well For frost bitten feet or limbs, for bee- as much better, it ought to come into general stings, for burns or scalds, even the most severe, I use with the public as an economical and most relief. efficient paint. It is well known to most paint- SKELETON LEAVES.-The following method has ers that white lead ground up in the common, been communicated to the Botanical Society of Edor even boiled linseed oil, and applied to exte-dissolving 3 oz. of washing soda in two pints of inburgh: "A solution of caustic soda is made by rior board surfaces, soon rubs off like whitewash boiling water, and adding 14 oz. of quick lime preupon the band. The hydraulic cement, ground viously slacked; boil for ten minutes, decant the in petroleum, seems to form a solid cement, or clear solution, and bring it to the boil. During artificial stone, and at one year old shows no ebullition add the leaves; boil briskly for some sign of rubbing off, though it may in the course time-say an hour, occasionally adding hot water to supply the place of that lost by evaporation. of time. Take out a leaf, and put it into a vessel of water, rub it between the fingers under the water. If the epidermis and parenchyma separate easily, the rest of the leaves may be removed from the solution, boiling must be continued some time longer. To and treated in the same way; but if not, then the bleach the skeletons, mix about a drachm of chlo ride of lime with a piot of water, adding sufficient acetic acid to liberate the chlorine. Steep the leaves in this till they are whitened, (about ten minutes,) taking care not to let them stay in too long, otherwise they are apt to become brittle. Put them into clean water, and float them out on pieces of paper. quite dry, and place them in a book or botanical Lastly, remove them from the paper before they are Mixed with sand and applied to leaky valleys between roofs, or around chimneys, it soon becomes as hard as stone. It might even answer for roofing when applied to felting; but I have never used it in this way. I have heard that there is a patent upon the use of petroleum as a paint oil, in what way applied I do not know. ITEMS. B. T. THE North Carolina Freedmen's Bureau reports that there are sixty thousand negro children in that State, twenty-five thousand of whom have been attending school during the past year. There are one hundred and twenty-five thousand poor white chil dren in North Carolina, but the Boston "Journal" says that no such proportion of these go to school. In fact, seven-tenths of them can neither read nor write. DR. LIVINGSTONE FURTHER ACCOUNTS GIVING HOPES OF HIS SAFETY.-At a meeting of the Royal Geographical Society in London, December 9, a letter was read from Dr. Kirk, of Zanzibar, fourteen days later in date than the last that have been pub lished. The letter is as follows: LETTER FROM DR. KIRK TO MR. WEBB. ZANZIBAR, Oct. 9, 1867. The interesting discovery that a white man had been seen, seven months ago, to the south of Lake Tanganyika, induced Mr. Churchill, the consul, and myself to go to Bangamoyo, a place on the coast, the point of arrival and departure of Ujiji caravans. The result of our visit has been to find two other men, who also saw this wanderer in the country of mouth of the Nile. -The Press. JOHN KIRK. DURING the six months preceding Eleventh month, the London underground railway carried over twelve millions of passengers, or about three times the population of London. The actual number transported over the line since its opening in First mouth, 1863, is about 70,000,000. press." Gossip." Dr. G. Dickson in "Hardwicke's Science THE Palestine exploration is making good progress. An official report, dated at Jerusalem on the 22d of Oct., says that Mr. Warner has established, by actual demonstration, that the south wall of the sacred enclosure which contained the Temple is buried for more than half its depth beneath an accumulation of rubbish, probably the ruins of the successive buildings which once crowned it, and that if bared to its foundation the wall would present an unbroken face of solid masonry of nearly one thousand feet long, and for a large portion of that distance more than one hundred and fifty feet in height; in other words, nearly the length of the London Crystal Palace and the height of the transept. Mr. Warren adds: height emerging from the ground, bas always been The wall, as it stands, with less than half that regarded as a marvel. What must it have been when entirely exposed to view? No wonder that Prophets and Psalmists should have rejoiced in the "walls" and "bulwarks" of the Temple, and that Tacitus should have described it as modo arcis construct im. The question immediately occurs, what does the lower part of the structure formed by this enormous wall contain, our present knowledge being confined to the existing level of the ground? Of this I can say nothing, though the passage discovered by Mr. Warren, thirty feet below the "single gateway," and described by him under October 224, promises to lead to important discoveries. The valley west of the Temple (Tyropoon) turns out to be very different in form from any thing bitherto supposed, viz: Tolerably flat for the greater part of its width, with am ple space for a "lower city," and suddenly descending close below the Temple wall to a narrow gully by Robinson, the centre of so many speculations, may of great depth. The well-known arch discovered thus prove to have been only a single opening to span this gully, instead of the commencement of a long bridge or viaduct.-Ledger. An editor getting tired of paying printers, resolved to put his own shoulder to the wheel. Here is a specimen of his effort at setting type: 'wa tqiny ze shyll do most oa Our wn setiNg tY Pe begrafier-PruterS ma tvLk about iTs bing difficult ro sEt tipe, bu‡ We dOn,t experienc |much difficultYi‘, FRIENDS' INTELLIGENCER. "TAKE FAST HOLD OF INSTRUCTION; LET HER NOT GO; KEEP HER; FOR SHE IS THY LIFE." VOL. XXIV. PHILADELPHIA, FIRST MONTH 11, 1868. No. 45. EDITED AND PUBLISHED BY AN ASSOCIATION OF FRIENDS. CONTENTS. The Penns and Peningtons....... COMMUNICATIONS MUST BE ADDRESSED AND PAYMENTS Blue River Quarterly Meeting.. MADE TO EMMOR COMLY, AGENT, At Publication Office, No. 144 North Seventh Street, TERMS: PAYABLE IN ADVANCE The Paper is issued every Seventh day, at Three Dollars per annum. $2.50 for Clubs; or, four coples for $10. Agents for Clubs will be expected to pay for the entire Club. Henry Haydock, Brooklyn, N. Y. William H. Churchman, Indianapolis, Ind. THE PENNS AND PENINGTONS. "He was very generous to the Irish Protes- 705 706 707 708 Address of Green Street Monthly Meeting of Friends................... 713 European Correspondence... Domestic Life.......... Review of the Weather, &c., for Twelfth Month.. ...... 720 diers. My husband, as he passed out, put in "He was most affectionately tender to me |