The periodical literature of the period may be divided into four classes. The first may be said to inch] de those papers— chiefly dailies—which make the publication of news, upon any and all subjects, their prime object. A second class including a large number oi weekly papers, and all the purely literary monthlies either make news subordinate, or omit all mention of facts as they occur, unless they ! can be made the text for some discussion, or otherwise sub-187serve some general literary purpose; general literature being the scope of this class of publications. A third class includes those papers and magazines devoted to some specific object, to the advancement of whose interests, and the collation of j news specially bearing upon it, their entire space is allotted. A fourth class comprises those devoted partially or exclusively to scientific literature, and to scientific news. It is of the latter class, wo propose to speak in the present article, confining ourselves to those published in America. I The sole claim any publication can make that can entitle it to public favor is, that it educates its readers. If it does not accomplish this it is a failure, unworthy of public patronage. I Whatever its scope may be, whether scientific, purely literary, or amusing, it should still educate, or it is worthless. More than this it should educate in the right way, or it is mental poison. The scientific press of the country claim more than any other department to instruct the masses, and the demand for popular scientific instruction is largely increasing in this country. Our own paper, which is the oldest of its kind published in the United States, has without doubt been largely instrumental in developing the present popular taste for scientific information, and its success is an evidence that it has supplied satisfactorily the public demand in this regard. The Journal of the Franklin Institute, the oldest monthly scientific periodical in this country, and SiUiman's American Journal of Science, the oldest quarterly scientific periodical, respectively fill places in American scientific literature which is occupied by no other. The SCIENTIFIC AMBEICAN also fills another and distinct place, and notwithstanding the many attempts which have been made, and are making, to compete with it, its progress is steady, and its circulation larger than at any former period of its history. The more recent publications devoted to scientific and industrial matters are the American Builder, Chicago; Sloan's ArcJdtectaral Eeviev), Philadelphia; Journal of Chemistry Boston; Industrial American, Manufacturer and Builder, American Artisan, Inventors' and Manufacturers' Gazette, New York; and Van Nostrand's Eclectic Magazine—a monthly which consists of articles copied from the current scientific literature of this country and Europe. The two numbers of this monthly already issued are well supplied, and the articles generally are selected with considerable care. We are happy to record a growing interest on the part of our people for a greater knowledge of scientific subjects.A Mechanical WhaleThe ingenuity. of man often manifests itself in curious shapes, a recent instance of which was brought to light in one of our city courts. It appearsthat a German,by the name of Gebhard, was employed by one of his countrymen to con struct a whale, to be exhibited as a veritable monster at liis " natatorium," or swimming tank, at the foot of Sixty-sixth street, on the East river. Gebhard set to work, and applied all his inventive and mechanical skill to produce a whale rivaling in appearance the famous creature which swallowed up Jonah. A nice mechanical contrivance was introduced inside the whalejwhereby it might be "vivified" and made to enact the part of the genuine thing. Gebhard then placed flaming advertisements in the newspapers, announcing himself as an eminent doctor and traveler who had just arrived from the Pacific ocean, where he had captured a monster whale, which would be exhibited on such a day at his " natatorium." 'Phis advertisement drew a large crowd of persons to the place designated on the day set down for the exhibition. But the amazement and delight of the people, who had paid to see the sight, were destined to be of short duration; for on the return of the whale to the " natatorium " one or two parties, who had secreted themselves for the purpose, saw four modern Jonahs emerge from his capacious belly, and a further inspection revealed the fact that the whole operations of his whaleahip in the water had been managed by machinery. The nonplussed Gebhard had to beat a speedy retreat, or he would have received rough treatment at the hands of the incensed crowd, who vented their chagrin on the now inanimate whs.le, and almost tore it to pieces. The party who employed Gebhard's skill, brought suit against him to recover sixty-seven dollars, the amount paid for constructing the animal, and, strange to say, the judge encouraged the swindle by giving judgment to the plaintiff.Carbon Printing by a Single TransferSome months ago M. Soulier submitted to the French Photographic Society numerous proofs (some of which were of very large dimensions) obtained by the carbon process. These proofs were on very thin but tough films, which remained perfectly flat during the development of the image, and could afterwards be applied to the cardboard with great exactness. There is no occasion to transfer the proof twice, as in Swan's process. M. Soulier operates as follows: He spreads on glass a very thin collodion; when this has been effected he covers it with a very thin layer of gelatin which is afterward rendered insoluble. On these two layers adhering together, he spreads, lastly, the sensitive mixture in which the image should afterward appear. After desiccation the film is easily detached from the glass and is sufficiently rigid to be handled. The exposure is made in the usual way as in Swan's process, and the washings are proceeded with afterward in the ordinary manner. When this is done nothing further remains but to paste the pellicule on the cardboard. M. Soulier showed by numerous specimens what could be achieved by this process, which is very economical and very quick. With the chromatized gelatin are mixed lampblack, carmine, sepia, purple, etc.