In the last "Annual of Scientific Discovery" are interesting notices of photographs of the sun, showing the spots on his disk, of Jupiter with his belts, and Saturn with his ring.
While the astronomer has been reducing the heavenly bodies to the dimensions of his stereoscopic slide, the anatomist has been lifting the invisible by the aid of his microscope into palpable dimensions, to remain permanently recorded in the handwriting of the sun himself. Eighteen years ago, M. Donné published in Paris a series of plates executed after figures obtained by the process of Daguerre. These, which we have long employed in teaching, give some pretty good views of various organic elements, but do not attempt to reproduce any of the tissues. Professor O.N. Rood, of Troy, has sent us some most interesting photographs, showing the markings of infusoria enormously magnified and perfectly defined. In a stereograph sent us by the same gentleman the epithelium scales from mucous membrane are shown floating or half-submerged in fluid,—a very curious effect, requiring the double image to produce it. Of all the microphotographs we have seen, those made by Dr. John Dean, of Boston, from his own sections of the spinal cord, are the most remarkable for the light they throw on the minute structure of the body. The sections made by Dr. Dean are in themselves very beautiful specimens, and have formed the basis of a communication to the American Academy of Arts and Sciences, in which many new observations have been added to our knowledge of this most complicated structure. But figures drawn from images seen in the field of the microscope have too often been known to borrow a good deal from the imagination of the beholder. Some objects are so complex that they defy the most cunning hand to render them with all their features. When the enlarged image is suffered to delineate itself, as in Dr. Dean's views of the medulla oblongata, there is no room to question the exactness of the portraiture, and the distant student is able to form his own opinion as well as the original observer. These later achievements of Dr. Dean have excited much attention here and in Europe, and point to a new epoch of anatomical and physiological delineation.
The reversed method of microscopic photography is that which gives portraits and documents in little. The best specimen of this kind we have obtained is another of those miracles which recall the wonders of Arabian fiction. On a slip of glass, three inches long by one broad, is a circle of thinner glass, as large as a ten-cent piece. In the centre of this is a speck, as if a fly had stepped there without scraping his foot before setting it down. On putting this under a microscope magnifying fifty diameters there come into view the Declaration of Independence in full, in a clear, bold type, every name signed in fac-simile; the arms of all the States, easily made out, and well finished; with good portraits of all the Presidents, down to a recent date. Any person familiar with the faces of the Presidents would recognize any one of these portraits in a moment.
Still another application of photography, becoming every day more and more familiar to the public, is that which produces enlarged portraits, even life-size ones, from the old daguerreotype or more recent photographic miniature. As we have seen this process, a closet is arranged as a camera-obscura, and the enlarged image is thrown down through a lens above on a sheet of sensitive paper placed on a table capable of being easily elevated or depressed. The image, weakened by diffusion over so large a space, prints itself slowly, but at last comes out with a clearness which is surprising,—a fact which is parallel to what is observed in the stereoscopticon, where a picture of a few square inches in size is "extended" or diluted so as to cover some hundreds of square feet, and yet preserves its sharpness to a degree which seems incredible.
The copying of documents to be used as evidence is another most important application of photography. No scribe, however skilful, could reproduce such a paper as we saw submitted to our fellow-workman in Mr. Black's establishment the other day. It contained perhaps a hundred names and marks, but smeared, spotted, soiled, rubbed, and showing every awkward shape of penmanship that a miscellaneous collection of half-educated persons could furnish. No one, on looking at the photographic copy, could doubt that it was a genuine reproduction of a real list of signatures; and when half a dozen such copies, all just alike, were shown, the conviction became a certainty that all had a common origin. This copy was made with a Harrison's globe lens of sixteen inches' focal length, and was a very sharp and accurate duplicate of the original. It is claimed for this new American invention that it is "quite ahead of anything European"; and the certificates from the United States Coast-Survey Office go far towards sustaining its pretensions.
Some of our readers are aware that photographic operations are not confined to the delineation of material objects. There are certain establishments in which, for an extra consideration, (on account of the difficilis ascensus, or other long journey they have to take,) the spirits of the departed appear in the same picture which gives the surviving friends. The actinic influence of a ghost on a sensitive plate is not so strong as might be desired; but considering that spirits are so nearly immaterial, that the stars, as Ossian tells us, can be seen through their vaporous outlines, the effect is perhaps as good as ought to be expected.
Mrs. Brown, for instance, has lost her infant, and wishes to have its spirit-portrait taken with her own. A special sitting is granted, and a special fee is paid. In due time the photograph is ready, and, sure enough, there is the misty image of an infant in the background, or, it may be, across the mother's lap. Whether the original of the image was a month or a year old, whether it belonged to Mrs. Brown or Mrs. Jones or Mrs. Robinson, King Solomon, who could point out so sagaciously the parentage of unauthenticated babies, would be puzzled to guess. But it is enough for the poor mother, whose eyes are blinded with tears, that she sees a print of drapery like an infant's dress, and a rounded something, like a foggy dumpling, which will stand for a face: she accepts the spirit-portrait as a revelation from the world of shadows. Those who have seen shapes in the clouds, or remember Hamlet and Polonius, or who have noticed how readily untaught eyes see a portrait of parent, spouse, or child in almost any daub intended for the same, will understand how easily the weak people who resort to these places are deluded.
There are various ways of producing the spirit-photographs. One of the easiest is this. First procure a bereaved subject with a mind "sensitized" by long immersion in credulity. Find out the age, sex, and whatever else you can, about his or her departed relative. Select from your numerous negatives one that corresponds to the late lamented as nearly as may be. Prepare a sensitive plate. Now place the negative against it and hold it up close to your gas-lamp, which may be turned up pretty high. In this way you get a foggy copy of the negative in one part of the sensitive plate, which you can then place in the camera and take your flesh-and-blood sitter's portrait upon it in the usual way. An appropriate background for these pictures is a view of the asylum for feeble-minded persons, the group of buildings at Somerville, and possibly, if the penitentiary could be introduced, the hint would be salutary.
The number of amateur artists in photography is continually increasing. The interest we ourselves have taken in some results of photographic art has brought us under a weight of obligation to many of them which we can hardly expect to discharge. Some of the friends in our immediate neighborhood have sent us photographs of their own making which for clearness and purity of tone compare favorably with the best professional work. Among our more distant correspondents there are two so widely known to photographers that we need not hesitate to name them: Mr. Coleman Sellers of Philadelphia and Mr. S. Wager Hull of New York. Many beautiful specimens of photographic art have been sent us by these gentlemen,—among others, some exquisite views of Sunnyside and of the scene of Ichabod Crane's adventures. Mr. Hull has also furnished us with a full account of the dry process, as followed by him, and from which he brings out results hardly surpassed by any method.
A photographic intimacy between two persons who never saw each other's faces (that is, in Nature's original positive, the principal use of which, after all, is to furnish negatives from which portraits may be taken) is a new form of friendship. After an introduction by means of a few views of scenery or other impersonal objects, with a letter or two of explanation, the artist sends his own presentment, not in the stiff shape of a purchased carte de visite, but as seen in his own study or parlor, surrounded by the domestic accidents which so add to the individuality of the student or the artist. You see him at his desk or table with his books and stereoscopes round him; you notice the lamp by which he reads,—the objects lying about; you guess his condition, whether married or single; you divine his