Our readers will find in another column an advertisement of this new building material which is now attracting much attention in the West, and of which we have received very favorable reports. It has been recently tested in Chicago with the result we are informed of fully establishing its utility. It is said that a house twenty-two feet long, sixteen wide, and fourteen high, can be covered on the outside for less than $9; and a house thirty-six feet by twenty-two, and twenty feet high, for $20. The building can be done at any season, and can be finished with great speed, and there are said to be numerous other advantages connected with the use of the paper. It differs from ordinary paper in consistency, compactness and solidity. In the manufacture it is subjected to a pressure of hundreds of tuns, which squeezes out the liquid matter, leaving a substance of the right thickness. It is said to be proof against damp and gnawing of vermin, and it being an excellent non-conductor of heat, must make a warm dwelling in winter and a cool one in summer. It is used in the place of plastering for inside walls. * * * * * The Prussian Government has military maps of every foot of its territory so complete that every hill, ravine, brooklet, field, and forest is delineated with perfect accuracy. It is a common boast of Prussian military men, that within the space of eight days 848,000 men can be concentrated to the defense of any single point within the kingdom, and every man of them will be a trained and well-equipped soldier. * * * * * Improved Muzzle-Pivoting Gun. We are indebted for the following able description and criticism of this Prussian gun to our able contemporary, _The Engineer_. Viewed as a piece of mechanism, nothing can well be more beautiful in mutual adaptation of parts to the fulfillment of given and rather recondite movements, and in point of execution, than this muzzle-pivoting arrangement of Herr Gruson's; but having said this we are compelled to add, as impartial engineering critics, that it is nothing more. [Illustration: GRUSON'S SYSTEM OF MUZZLE-PIVOTING APPLIED TO MONITORS.]