All these objections are overcome by the invention of stone-paper. The material advantages of it are as follows: (1) The cost is much smaller than that of a stone of equal size. (2) The weight is inconsiderable; a plate of letter-sheet size weighs scarcely four ounces. (3) Hundreds of such plates piled on each other require scarcely as much space as a single stone, and can, therefore, be stored or shipped easily. (4) They resist the most powerful press better than do stone, copper, and even iron plates. Their inner elasticity supports the most extreme pressure without alteration if only they are handled properly. (5) The application of fatty inks, and also engraving with the steel graver is easier. Indeed, because of the great toughness of the stone-paper, the engraving process approaches copper engraving more closely. (6) Inking and printing are easier, and demand no such powerful pressure, because the artificial stone receives and imparts color more readily, than does the natural stone. (7) Finally, they are so excellent for all methods of printing that it is possible to reproduce the original plates at will merely by transferring a fresh imprint to another plate. And this can be done with such accuracy that none of these plates can be distinguished from the original, so that the stone-paper surely must become of enormous importance for stereotyping in the book-printing trade. These advantages, and others to be described on suitable occasion, elevate this invention unquestionably to the highest importance in the art of chemical printing, despite all that may have been said recently by a certain writer whose lack of knowledge forbade correct judgment. The matter already has attained a degree of perfection that makes every further improvement unnecessary, nay, almost impossible. My many employments, mostly caused by the publication of this text-book, thus far have prevented the erection of my own manufactory for making these artificial stone-plates or stone-paper. I hope to do it soon, and then everybody can convince himself of the truth of my assertions, if he will use the material according to my instructions. This invention will facilitate the introduction of lithography in all places, because one can make the stones himself. However, lithography has expanded very considerably in its present form, and has been brought into use in the foremost cities of Europe. For instance, it was introduced into France and England, first by Herr Andre, in latter days by the Count von Lasterie in Paris and Herr Ackermann in London, being utilized for many kinds of printed work. In Berlin, Herr Major von Reiche has erected a great institution. In Petersburg the art has existed for some years, and is being especially well cultivated now by Freiherr von Schilling. The art has entered even Philadelphia, and, more extraordinarily, Astrakan, and, so far as I can learn, has been welcomed heartily.