SPRING 



5509 



SPRINGBOK 



springs are merely outlets of some underground 

 streams, while others bubble up from a small 

 opening. Some very large springs are the 

 surface outlets of underground rivers. Most 

 springs flow constantly except in seasons of 

 severe drought, but occasionally we find those 

 which flow periodically, sometimes at intervals 

 of a few minutes or hours, and sometimes at 

 longer periods. These are called periodic or 

 intermittent springs. The flow of some of 

 these springs is accounted for by the varying 

 amount of water in the ground. They become 

 active after a heavy fall of rain and usually 

 flow during the spring, when the melting snow 

 has saturated the ground. The flow of others 

 is not understood. 



The temperature of springs is nearly the 

 same as that of the underground rock over 

 which the water flows. Cool springs have deep 

 sources, whose temperature is not affected by 

 climatic changes. The temperature of these 

 springs varies but little throughout the year. 

 On the other hand, a spring whose source is 

 near the surface will be much warmer in sum- 

 mer than in winter. In volcanic regions the 

 water may come in contact with hot layers of 

 rock, and when this occurs a hot, or thermal, 

 spring is found. 



Water, in filtering through the ground, dis- 

 solves carbonate of lime and various other 

 minerals. Springs whose waters contain these 

 substances in solution are known as mineral 

 springs. Various gases, such as carbon dioxide', 

 sulphureted hydrogen and nitrogen, are also 

 found in the water of these springs. Some min- 

 eral springs have become noted health resorts 

 because of the curative properties of their 

 waters. Saratoga Springs, N. Y., the springs at 

 Carlsbad, Germany, and the hot springs at 

 Las Vegas, N. M., are good examples of such 

 springs. W.F.R. 



Consult Schlicter's Motion of Underground 

 Water,, in United States Geological Survey Bulle- 

 tin No. 67. 



Related Subjects. The reader is referred to 

 the following articles in these volumes : 

 Artesian Well Thermal Springs 



Mineral Waters Water 



SPRING, that quality of a material by virtue 

 of which it can "spring back," or resume a posi- 

 tion from which it has been forced by tension. 

 It is a characteristic of such materials as steel 

 wire or rods, India rubber, whalebone or wood. 

 The term spring is also applied to various de- 

 vices and mechanisms. 



In carriages, automobiles and other vehicles 

 springs are used between the axles and the 



body of the vehicle to decrease concussion. In 

 watches and clocks they are used to produce 

 motion, being wound rather tightly around a 

 central post, then gradually unwinding and im- 

 parting power to the mechanism. Springs may 

 return to their natural position slowly, as in 

 the case of the mainspring of a watch, or 

 quickly, as in a gun or rifle, in which the 

 spring is suddenly released from high tension, 

 setting in motion the hammer, or pin, which 

 explodes the charge. The quick action of a 

 spring also occurs when a bow is bent and the 

 cord is released. In the familiar spring-balance 

 scales used in stores, the spring causes an indi- 

 cator to move according to the tension. The 

 weight of the article on the scale is ascertained, 

 and when this is removed the spring resumes its 

 normal position. 



SPRING 'BOK, or SPRING 'BUCK, a species 

 of South African antelope, the nearest ally of 

 the true gazelles, so named from its habit of 

 springing upward when alarmed or at play. 

 Among the Dutch settlers it is known as trek- 



THE SPRINGBOK 



bokken, or traveling buck. Large herds travel 

 through the country, clearing the plains of 

 grass, and seemingly guided by instinct to seek 

 those sections where rains have caused the 

 vegetation to spring up again. These animals 

 are a source of anxiety to farmers, whose flocks 

 of sheep and goats they often kill. The spring- 

 bok is exceedingly graceful, and the most slen- 

 derly built of all antelopes. Its coat is close 

 and short, of a dull brown color, with a white 

 stripe extending the length of the back. The 

 horns curve in' the shape of a lyre, and in the 

 female are shorter and not so deeply ringed as 

 in the male. The skin is valuable, and when 

 in good condition the flesh is said to be excel- 

 lent for food. 



