HIPPOCAMPUS 



2799 



HIPPODROME 



made remarkably accurate observations of the 

 heavens, and on these his fame rests. He pre- 

 pared a catalogue of 1,080 fixed stars, classified 

 according to brightness. Ptolemy later used 

 this catalogue and preserved it for future gen- 

 erations. 



Hipparchus also observed and calculated the 

 exact length of the seasons, the length of the 

 year and the motions of the planets and the 

 moon in their orbits. Not only did he observe 

 all these things, but he was also able to make 

 records of them for those who should follow. 

 In order to do this he had to enter the hitherto 

 unknown sphere of higher mathematics, so he 

 originated what is now known as trigonometry; 

 he also designed the planisphere, a diagram of 

 the heavens with 'a circular cover, which when 

 moved shows the exact positions of the heav- 

 enly bodies at different times. 



HIPPOCAMPUS, hipokam'pus, or SEA 

 HORSE, a genus of oddly-formed sea animals, 

 belonging to the same family as the pipefish 

 (see PIPEFISH). There are about twenty spe- 

 cies, inhabitants of tropical and temperate 

 waters. The name hippocampus, which comes 

 from two Greek words meaning horse and sea 

 monster, was given this animal because of the 



i 



THE HIPPOCAMPUS 



similarity between its head and that of a horse, 

 A hippocampus has a protruding snout, promi- 

 nent eyes and high cranium, and is like a fish 

 only in that it lives in the sea and breathes by 

 gills. Its body, from six to ten inches in 

 length, ends in a long tail which is tightly 

 coiled inward, and the animal is covered with 

 a series of bony plates which have spiny pro- 

 jections along the places of connection. It 

 moves about in an upright position, but is a 



weak swimmer, and usually is found with the 

 tail clinging tightly to bits of seaweed. As is 

 true of the pipefish, the male hippocampus 

 keeps in a pouch on the under side of its body 

 the eggs laid by the female, and they are taken 

 care of there until hatched. 



HIPPOCRATES , hip ok ' ra teez (460-357 

 B.C.), the greatest of the old Greek physicians, 

 often called the "Father of Medical Science," 

 was born on the island of Cos, off the coast of 

 Asia Minor. He was believed by the Grecians 

 to be the descendant o a god, and he became 

 a priest-physician. Hippocrates used temples 

 as hospitals, which had a full measure of pure 

 air, water . and sunshine ; while the patients 

 offered petitions to their heathen gods they 

 were treated for their ailments by Hippocrates 

 and his disciples. One of his discoveries was 

 that certain diseases could be traced by listen- 

 ing to the sounds made in the chest of a per- 

 son, but this knowledge did not become really 

 useful until 2,000 years later. He bound his 

 students' by a solemn promise to behave with 

 honor and never to divulge a sick-room secret. 

 His writings embrace books on epidemics, air 

 and water, and on diet and hygiene. He trav- 

 eled throughout Greece and died at an ad- 

 vanced age in Thessaly. 



HIPPODROME, hip'odrohm, originally a 

 place set apart by the ancient Greeks for horse- 

 and chariot-racing, and later for boxing, 

 wrestling, running, etc. The most famous 

 ancient hippodromes were those of Olympus 

 and Constantinople and the Circus Maximus at 

 Rome. These were of vast proportions, accom- 

 modating from 100,000 to 500,000 spectators. 

 The term has also been applied to race tracks 

 in England and France, to the modern indoor 

 circus and, in particular, to two great amuse- 

 ment palaces, in London and in New York. In 

 the latter city the structure occupies an entire 

 block on Sixth Avenue, between 43rd and 44th 

 streets; it was begun on July 1, 1904, and 

 completed in five months. It is the largest 

 playhouse in the world, having a seating 

 capacity of 5,200, and cost $1,750,000. Many 

 interesting and novel features are connected 

 with the stage mechanism. The stage, which 

 will easily accommodate 500 people in a single 

 action, is circular, and while one half is before 

 the audience the other half is being prepared 

 for the scene to follow. An immense tank in 

 front of the stage, a part of the stage acces- 

 spries, capable of accommodating over twenty 

 rowboats, can be filled with water in five min- 

 utes. 



