Page:Popular Science Monthly Volume 42.djvu/736

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THE POPULAR SCIENCE MONTHLY.

fore-and-aft schooner. The expedition is expected to start in the spring. It will try to make the farthest possible point north in open water, and, when it can get no farther, will run into the ice at the most favorable spot, and from there trust entirely to the current running across the polar region. The possibility of the ship being, after all, crushed by the ice is provided against by having two boats aboard, with which the men will move with their provisions upon the ice and camp there. Thus the journey would be continued, with the only difference that there would be two small ships standing on the ice instead of the big one lying between the floes. When they emerged into the open sea on this side of the pole there would not be any great difficulty in the boats; such a thing had been done many times before. The chief difficulty would be to get duly into the current north of Siberia; when this was done, they must be carried some where northward. Whether he succeeded or not, the author was convinced that this was the way in which the unknown regions would some day be crossed. Possibly the current would not carry them exactly across the pole, but it could not easily be very far off; and the principal thing was to explore the unknown polar regions, not to reach exactly that mathematical point in which the axis of our globe has its northern termination.

 

Terra Cotta Roofing Tiles.—In his very interesting study of that subject, Prof. Morse mentions it as a noteworthy fact that the earliest type of terra cotta roofing tile ever exhumed still forms the roof covering of the greater mass of mankind to-day. The enduring nature of these objects, he adds, will ultimately enable one to trace the paths followed by tile-making races in their various migrations. The roofing tile has a considerable antiquity, for its appearance in Greece dates back to the earliest dawn of Greek art; and yet before this, in Asia Minor, there was a time when the tile was not, for, though in Schliemann's Ilios many other kinds of pottery were found in great abundance, there was no trace of tiles. It is probable that the roofing tile was introduced into Greece from the East fully developed. The sloping roof must have preceded the roofing tile by many thousands of years; at the outset, bark, straw, thatch, rough stones, and similar substances were used until better devices were made, which finally terminated in the terra cotta roofing tile. The shape of the earliest form of tile—a normal tile, as Prof. Morse calls it—suggests its derivation from the bark thatch. It consists of a wide under piece (tegula) slightly curved, and a narrow semi-cylindrical piece (imbrex), which was placed in an inverted position so as to cover the junction of two adjacent tegulæ. So, in roofing with bark, we would put down two pieces, concave side up, and cover the crack between them with a piece concave side down. A second type of tile is the pan tile or S-tile, which has a double flexure, forming in section a figure like that of the letter S laid upon its side (S-laid.svg). This is an evident adaptation from the normal tile, in which the two elements, imbrex and tegula, are combined in one piece. A third type, the flat tile, or plain tile, has no genetic relation to the other forms, but is simply a shingle in terra cotta. With few exceptions, the normal tile is the only form used in Asia, Asia Minor, Greece, Italy, Sicily, Spain, the countries bordering the southern shores of the Mediterranean, and all the Spanish and Portuguese countries and colonies in both hemispheres. The pan tile, or Belgic tile, prevails in the countries around the North Sea and the Baltic; and the flat tile in France and central Europe, away from the Mediterranean.

 

The Disinclination to meditate.—A suggestive essay is published in the London Spectator on the Dread of Thought, in which, remarking upon the necessity of people having something with which to occupy their minds—a book, for instance—when left to themselves, the writer asks the questions: "Why is it natural for a man to dread being thrown back upon his own thoughts? Why should he find meditation so unnatural, and reading so natural? "The writer believes that the dread of thought (a little too strong a term, for it is really rather a neglect or ignoring of thought) "in a great measure comes from lack of habit. All children pass a good deal of time in thinking, but men, in the press of business and pleasure, forget how to think, and grow to regard reading as the only possible way of passing the time quietly. . . . We venture to think, however,