The principal floor of this design is elevated three feet above the surface of the ground, and is approached by the front steps leading to the platform. The height of the first floor is eleven feet, the second ten feet, and the cellar six feet six inches in the clear. The porch is so constructed that it can be put on either the front or side of the house, as it may suit the owner. The rooms, eight in number, are airy and of convenient size. The kitchen has a range, sink, and boiler, and a large closet, to be used as a pantry. The windows leading out to the porch will run to the floor, with heads running into the walls. In the attic the chambers are 10x10 feet, 13x14 feet, 12x13 feet, 10x10½ feet, and a hall 6 feet wide, with large closets and cupboards for each chamber. The building is so constructed that an addition can be made to the rear any time by using the present kitchen as a dining room and building a new kitchen. [Illustration: A MANSARD ROOF DWELLING. First Floor.] [Illustration: A MANSARD ROOF DWELLING. Second Floor.] These plans will prove suggestive to those contemplating the building of a new house, even if radical changes are made in the accompanying designs.--_American Cultivator_. [Illustration: A MANSARD ROOF DWELLING. Front Elevation.] * * * * * THE HISTORY OF THE ELECTRIC TELEGRAPH. [Footnote: Aug. Guerout in _La Lurmière Electrique_.] An endeavor has often been made to carry the origin of the electric telegraph back to a very remote epoch by a reliance on those more or less fanciful descriptions of modes of communication based upon the properties of the magnet. It will prove not without interest before entering into the real history of the telegraph to pass in review the various documents that relate to the subject. In continuation of the 21st chapter of his _Magia naturalis_, published in 1553, J. B. Porta cites an experiment that had been made with the magnet as a means of telegraphing. In 1616, Famiano Strada, in his _Prolusiones Academicæ_, takes up this idea, and speaks of the possibility of two persons communicating by the aid of two magnetized needles influenced by each other at a distance. Galileo, in _Dialogo intorno_, written between 1621 and 1632 and Nicolas Caboeus, of Ferrara, in his _Philosophia magnetica_, both reproduce analogous descriptions, not however without raising doubts as to the possibility of such a system. A document of the same kind, to which great importance has been attached is found in the _Recreations mathematiques_ published at Rouen in 1628, under the pseudonym of Van Elten, and reprinted several times since, with the annotations and additions of Mydorge and Hamion and which must, it appears, be attributed to the Jesuit Leurechon. In his chapter on the magnet and the needles that are rubbed therewith, we find the following passage.