314 



THE CENTURY BOOK OF FACTS. 



Dyeing is attributed to the Tyrians, about 

 1500 B. C. The P^nglish are said to have 

 sent fine goods to be dyed in Holland till the 

 'art was brought to them, probably in 1608. 

 A statute against abuses in dyeing passed in 

 1783. The art has been greatly improved by 

 chemical research. Among the most promi- 

 nent names connected with the art of dyeing 

 is that of Dr. Stenhouse, who in 1848 invented 

 a number of beautiful dyes, mauve, magenta, 

 red, green, black. 



Dynamite. As generally manufactured, 

 dynamite consists of infusorial earth, porce- 

 lain earth, coal-dust, siliceous ashes or the 

 like, saturated with about three times its 

 weight of nitro-glycerine, a compound which 

 is produced by the action of a mixture of 

 strong nitric and sulphuric acids on glycerine 

 at low temperatures, though the proportions 

 vary with different makers. According to its 

 elements, it is to the eye a grayish-brown, 

 reddish, or blackish powder, damp and greasy 

 to the touch, and without smell. Its explo- 

 sive power is about eight times greater than 

 that of gunpowder. The manufacture of dyna- 

 mite is attended with great danger, owing to 

 the proneness of nitro-glycerine to explosion 

 even at the slightest shock. .The explosive 

 force of the latter substance, which has the 

 appearance of common oil, is about ten times 

 greater than that of gunpowder. 



Dynamite Gun. The nitro-gelatine or 

 dynamite gun, known as the " Zalinski gun," 

 was the invention of Lieutenant Zalinski and 

 Captain Bartlett of the United States army. 

 It is a long tube made of wrought iron, lined 

 with seamless brass tubing one eighth of an 

 inch thick. The projectile used is shaped like 

 a huge rocket, five or six feet in length. The 

 stick of the rocket has a wooden or metal base 

 large enough to fill the bore of the gun, and 

 against this base the pressure of the air (the 

 propelling force being compressed air) 1,000 

 pounds to the square inch is exerted. The 

 head of the rocket contains from fifty to sixty 

 pounds or more of nitro-gelatine, a new 

 explosive made of nitro-glycerine and gun- 

 cotton. The projectile, being shot from the 

 gun, is exploded, after reaching its mark, by 

 electricity. A small battery is fixed in the 

 head of each shot^ and the discharge is effected 

 by concussion if the shot strikes, or by action 

 of water on a sensitized surface if the shot 

 lights in the sea. It is thought that a sub- 

 marine explosion within 100 feet of a ship will 

 be disastrous in eight cases out of ten. The ! 

 gun is from 40 to 75 feet in length, and of cal- j 

 iber from 6 to 10 inches. The mechanical ar- 

 rangement for compressing the air in the gun 

 and discharging the piece is said to be taken 



i from an invention of B. T. Babbitt, patented 

 in 1878. 



Earth's Surface, The. The earth's 

 surface covers an area of about 197,000,000 

 i square miles, of which only about one fourth 

 is land. 



- Lowland* are tracts, either level or diversified 

 by hill and vale, not elevated more than 1,000 

 feet above sea-level. Deserts are extensive 

 tracts destitute of water, and, consequently, of 

 vegetation and animal life. 



Silvas are forest plains. Plains that produce 

 grass, but not trees, are known in North Amer- 

 ica as prairies ; in South America as //</>/o.vand 

 pampas ; in Asia and Southeastern Europe as 

 steppes. 



The desert of Sahara, as far as known, con- 

 sists partly of table lands and partly of low 

 plains. It is interspersed with oases, or fertile 

 spots, which are generally lower than the sur- 

 rounding country ; some of these are of con- 

 siderable extent and well populated. 



A mountain is an elevation of land exceed- 

 ing 2,000 feet in height. A hill is less than 

 2, 000 feet in height. 



A mountain chain is a long, elevated ridge, 

 or several mountains extending in a line. 



Mountains are of great use to man. They 

 attract the clouds, condense their moisture, 

 and store up in reservoirs the water received 

 from them, sending it forth again in streams, 

 from thousands of springs, to fertilize the soil. 

 They increase the surface of the earth, giving 

 variety to its vegetable productions. They 

 protect the adjacent countries from cold and 

 piercing winds, and thus exert a favorable in- 

 fluence on their climate. 



An avalanche is a large mass of snow, ice, 

 and earth, sliding or rolling down a mountain. 

 A water shed is the mountain chain or ridge. 

 of land which separates one basin from 

 another, and from which the .rivers flow. 



A mountain /in** is an elevated road crossing 

 a mountain chain through a natural opening 

 or depression. 



Glaciers are immense masses of ice formed 

 by the accumulated snows upon the mountain 

 tops. They fill in vast valleys, and have an 

 onward motion throughout like a liquid or 

 semi-liquid body. Their course down the 

 slopes is very slow, but, like rivers, they now 

 faster in the middle than at the bottom and 

 sides. The lower extremities are constantly 

 melting, forming torrents and mountain 

 streams, while the upper parts are fed by the 

 snows. Rocks of immense size are torn off 

 and carried down by glaciers. They occur in 

 the greatest numbers in the Alps. When a 

 glacier reaches the ocean large fragments are 

 broken off and float away as icebergs. 



