APSIDES 



distinctive feature of April is its showers. 

 Changes from flashing sunlight to pouring rain 

 are frequent, and William Watson's lines- 

 April. April, 



Laugh thy golden laughter, 



But, the moment after, 



Weep thy golden tears ! 



give as good a picture of the month as can be 

 expressed in words. 



April has played a curious part in United 

 States history, for nearly every war in which 

 the country has been involved has begun in 

 this month the Revolution, the Mexican War, 

 tlu- War of Secession, the Spanish-American 

 War, and the War of the Nations. This last 

 war did not begin in that month, but in April 

 the United States entered it. 



Special Days. April has several special 

 days. The first day is April Fools' Day, or 

 All Fools' Day (which see) ; it is not a holiday, 

 but a time dear to children by reason of the 

 sanction it gives to mischievous, harmless 

 pranks. Almost always Easter falls in April, 

 and fittingly, too, for it is the symbol of that 

 broader new life of which April represents one 

 phase. Canada has no fixed days in this month 

 for celebration, but many states in the Amer- 

 ican Union have set aside one day for the 

 planting of trees and have called it Arbor Day 

 (which see). 



APSIDES, ap'sideez, in astronomy, two 

 points in the orbit of a heavenly body, one 

 farthest away from, the other nearest to the 

 body about which it revolves. This is most 

 clearly illustrated by the point at which the 



304 AQUAPLANING 



earth). The earth is in perihelion (meaning 

 around or near the sun) when nearest the sun; 

 in aphelion (meaning away from the sun), 

 when at its extreme distance from it. The line 

 of apsides has a slow forward and westward 

 motion in the plane of the orbits of all planets, 

 except in that of Venus, when the motion is 

 reversed. This is due to what is called pre- 

 cession (see PRECESSION OF THE EQUINOXES). 

 APTERYX, a bird about the size of u hen, 

 without wings or tail and having a long, slender 

 beak, with nostrils near the tip. Its plumage, 

 of a grayish brown color, is more like hair 

 than feathers. It is a very timid bird, hiding 



APSIDES 



moon is at its greatest distance from the earth 

 and the point at which it is nearest. An imag- 

 inary line drawn between these two points is 

 called the line oj apsides. The accompanying 

 diagram shows the apsides at a a. 



When the moon is at its nearest approach 

 to the earth it is said to be in perigee (mean- 

 ing around or near the earth) ; when most 

 distant, in apogee (meaning away from the 



THE APTERYX 

 It is about seven inches in height. 



by day and feeding at night on worms, insects 

 and seeds. In a burrow it scratches a nest, 

 where it lays two large, white eggs. The 

 natives of New Zealand call it kiwi-kiwi, on 

 account of its peculiar cry. It is fast becoming 

 extinct, as it breeds very slowly and great 

 numbers are destroyed by natives, who are 

 particularly fond of its flesh. 



AQUAMARINE, a fine and transparent 

 variety of beryl much prized as a gem, of a blue 

 or sea-green color. The stone is found in 

 Siberia and Brazil, and in the United States in 

 Colorado and North Carolina. According to 

 an old superstition the aquamarine was worn 

 to counteract the effects of poison. With the 

 bloodstone it is a birth gem for March. See 

 BERYL. 



AQUAPLANING, ak' wa play n ing, a new 

 and exhilarating sport enjoyed by water en- 

 thusiasts who desire something more exciting 

 than swimming. The aquaplane is a small 

 raft attached by a rope to the stern of a 

 swiftly-moving motor boat. Another rope, the 

 ends of which are fastened to the front corners 

 of the raft, serves as a driving rein and sup- 



