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THE POPULAR SCIENCE MONTHLY. 



fore-and-aft schooner. The expedition is ex- 

 pected to start in the spring. It will try to 

 make the farthest possible point north in 

 open water, and, when it can get no far- 

 ther, will run into the ice at the most favor- 

 able 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 north- 

 ward. 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 prin- 

 cipal thing was to explore the unknown polar 

 regions, not to reach exactly that mathemat- 

 ical 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. E. S. 

 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 en- 

 during nature of these objects, he adds, will 

 ultimately enable one to trace the paths fol- 

 lowed by tile-making races in their various 

 migrations. The roofing tile has a consider- 

 able 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 

 Schliemami's Ilios many other kinds of pot- 

 tery 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 sub- 

 stances 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 

 (tcffula) 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 tcgulce. So, in roof- 

 ing 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 sec- 

 tion a figure like that of the letter S laid 

 upon its side (m ). This is an evident adap- 

 tation 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 sug- 

 gestive essay is published in the London 

 Spectator on the Dread of Thought, in which, 

 remarking upon the necessity of people hav- 

 ing 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 ig- 

 noring 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, 



