790 



HORROCKS 



HORSE 



Horrocks. JEREMIAH, an astronomer of re- 

 markable genius, generally known as the first 

 observer of the transit of Venus, an account of 

 which phenomenon he has given in a Latin treatise 

 entitled Venus in Sole visa. He was born at Tox- 

 teth, near Liverpool, apparently in 1619 ; he entered 

 Emmanuel College, Cambridge, May 18, 1632; was 

 appointed in 1639 to the curacy of Hoole. Lanca- 

 shire, in which village he made his famous observa- 

 tion (November 24, 1639, O.S.), while a mere youth. 

 He died suddenly on January 3, 1641, the day 

 before an intended journey, having promised to 

 visit his chief friend, William Crabtree. Dr Wallis, 

 his contemporary, informs us that Horrocks at the 

 time of his death ' had not completed his twenty- 

 third year.' Newton, in the Principia, bears 

 honourable testimony to the value of Horrocks's 

 astronomical work, especially commending his 

 lunar theory as the most ingenious yet brought 

 forward, adding, ' and, if I mistake not, the most 

 accurate of all. ' Horrocks is frequently mentioned 

 by the scientific men of the 17th century ; the 

 observation of the transit being by no means re- 

 garded as his sole astronomical achievement, as he 

 added to our knowledge of the physical cause of 

 celestial motions, deduced the solar parallax, cor- 

 rected the solar diameter, and made tidal observa- 

 tions. Hevelius printed the Venus in Sole visa, 

 which first appeared in Germany ( 1662) ; a transla- 

 tion of this work, with memoir by Whatton, ap- 

 peared at London in 1859. In 1678 Horrocks's frag- 

 mentary works were published under the auspices 

 of the Royal Society, being edited by Dr Wallis, 

 with the title Jeremice Horroccii Opera Posthuma, 

 &c. The name of Jeremiah Horrocks, long for- 

 gotten except by astronomers, is now, ' after the 

 lapse of more than two centuries,' engraven on 

 marble in Westminster Abbey. 



Horse (Equus), an ungulate or hoofed mammal 

 of the order Perissodactyla, characterised toy hav- 

 ing an odd number of toes ; the family Equidse 

 formed the group Solidungula of old writers, owing 

 to the presence of only a single hoof, which marks 

 them off quite sharply from all allied animals. 

 The English name is found in Anglo-Saxon as hors, 

 and is cognate with the Icelandic hross, German 

 ross; it is sometimes referred to Sanskrit root 

 hresh, ' to neigh,' but, according to some, with more 

 probability, to a Teutonic root har, ' to run,' cog- 

 nate with Latin currere. The Latin name is no 

 doubt from the root ak, conveying the idea of 

 swiftness ; Sanskrit aq va ; Gr. hippos or hikkos ; 

 Lat. equus. 



The existing species of the genus Equus are 

 about half a dozen in number : ( 1 ) The Horse (E. 

 caballus) is characterised by the tail being furnished 

 with long hairs quite from its base ; by the long 

 and flowing mane ; by the possession of a bare 

 callosity on the inner surface of the hind as well as 

 of the fore legs ; and by the head and ears being 

 smaller and the limbs longer than in the other 

 species. (2) The Ass (E. asinus) is almost as 

 widely distributed as the horse ; it is probably of 

 African origin, being almost certainly conspecific 

 with the Abyssinian form, E. tceniopus. (3) The 

 Asiatic Ass ( E. hemionus ) differs from the common 

 ass in being of a more reddish colour, in the absence 

 of the shoulder stripe, and in having smaller ears. 

 By some zoologists it is split up into three species 

 the Syrian Wild Ass (E. hemippus), the Onager 

 (E. onager), and the Kiang or Dziggetai, to which 

 the term E. hemionus then becomes restricted. 

 ( 4 ) The Quagga ( E. quagga ) has dark stripes upon 

 the head and shoulders on a brown ground ; it 

 is said to be now extinct. (5) BurchelFs Zebra 

 (E. Burchelli) is white, with stripes on the 

 body and the upper parts of the limbs ; it 

 extends from the Orange River to Abyssinia. 



(6) The Mountain Zebra (E. zebra) is white, 

 with long black stripes reaching down to the 

 feet. It is limited to the Cape Colony, and 

 is rapidly disappearing. These last three are 

 sometimes united into a special genus, Hippotigris. 



(7) The explorations of the Russian traveller 

 Przhevalski (Prejevalsky ) in 1881 added another 

 species to the list of Asiatic forms, which has been 

 called after him. The long hairs of the tail begin 

 only half-way down it ; the mane is short and 

 erect, and there is no forelock ; the head is large 

 and heavy ; the ears smaller than those of the 

 ass. It inhabits the dry sultry regions of the 

 Dzungarian Desert, living in companies of fifteen 

 to twenty, each led by a stallion. Only two herds 

 were observed, and only one specimen was secured. 

 The resemblance which this species presents to the 

 horse of early sculptures has been pointed out by 

 several observers. 



Horse, witli names of parts : 



1, crest ; 2, withers ; 3, croup ; 4, hamstring ; 6, hock ; 6, 

 cannon ; 7, fetlock ; 8, pastern ; 9, hoof ; 10, coronet ; 11, 

 arm ; 12, gullet ; 13, muzzle. 



The anatomical structure of the horse has toeen 

 the subject of many elaborate treatises, and only 

 a very brief outline of its more salient features can 

 be offered here. The skull is remarkable for its 

 great length, especially as regards the bones of the 

 Face, which occupy an extent twice as great as 

 those of the cranium. The orbit is approximately 

 circular and complete behind, a fact which dis- 

 tinguishes the horse from the tapir and rhinoceros, 

 as well as from its fossil allies. The co-operation 

 of the zygomatic process in the formation of the 

 lower part of the orbit is an unusual if not a 

 unique feature. The great cheeks are formed 

 mainly of the maxillary bones, though the lachry- 

 mal and malar bones occupy a considerable area in 

 the upper portion. The nostrils are roomy, pro- 

 vided with extensive turbinal bones, and roofed 

 in by the nasal bones, which are broad behind, 

 pointed in front. In the naked skull the anterior 

 openings of the nostrils extend far back at either 

 side between the nasal and premaxillary bones. 

 The palate, like the floor of tne cranium, is long 

 and narrow, forming a kind of valley between the 

 two rows of elevated molar teeth. Below the 

 brain-case there is a distinct canal through the 

 alisphenoid bone for the internal maxillary artery. 

 In the region of the ear the tympanic and periotic 

 bones are fused together, but are loose from the 

 skull, being held in position only by the descend- 

 ing process of the squamosal bone. The hyoid 

 bone is well developed, especially as regards its 

 anterior arch, and the basal segment sends a 

 process forward into the tongue. The rhinoceros 

 and tapir have a similar, but smaller, process. 

 The mandible is very large, and the lower and 

 hinder part is expanded into a broad flat plate for 

 the attachment of the masseter muscle. The verte- 

 bral column is made up of seven cervical, eighteen 



