108 NATURAL HISTORY OF THE FARM 
this. The horse was kept for use in war mainly. Some 
peculiarities of his mental make-up seem to fit him for the 
parade ground. He seems to love excitement. He enters 
into a race with great zest. He steps high in public and 
wears the trappings of war with all the proud disdainfulness 
of a Cavalier. He has given his name to one ostentatious 
period of our history, the Age of Chivalry. 
To the Greeks we probably owe an invention of the first 
order, that has adapted the horse more fully to our needs: 
the iron shoe, to fit his foot for continuous travel over hard 
roads. The cloven foot of the ox could not be so equipped. 
It was adapted for soft ground and could not endure hard 
roads. The horse gradually took the place of the ox, first on 
the roads and later in the furrow. The horse was both 
swifter of foot and stronger. Do we not still measure the 
energy used for heavy work in horse-power? 
To our welfare sheep have contributed of their flesh and 
their wool. The latter is their unique gift to us. Man’s 
earlier clothing of skins was heavy and unadaptable and 
unhygienic. Sheep’s wool is finely adapted to be spun into 
threads and woven into cloth; and, so treated, it makes the 
strongest and best of clothing. The discovery of this art 
wrought one of the greatest advances in the comforts of life 
for people in temperate climes. Sheep do not belong to the 
tropics. They are adapted to life in rough, hilly, semi- 
agricultural districts. They are less exacting as to forage 
than are cattle, and being strictly gregarious, the flocks 
are more easily herded and guarded from the attack of wild 
beasts. They are quicker of growth than cattle, and more 
prolific, and less capital is required to make a beginning at 
sheep-raising. 
The pig has served us mainly as a supplementary food 
supply. He puts on flesh quickly and is very prolific. 
Hence, the meat supply can be more quickly increased by 
