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KEVV GARDENS. 
also the whole retinue and army of the Persian king for four 
months in the year; that one of the Satraps owned 16,800 
horses, and that his dogs were so numerous that four large 
villages were excused from all other taxes on condition of 
supplying them with food. He says that the soil of the 
Babylonian plain was so fertile that of wheat it yielded a 
return of two or three hundredfold, that millet and sesamum 
grew to a great size, and that over the whole plain the date 
palm flourished, bearing fruit abundantly. Now for centuries 
the plain has been a sandy desert, without any regularly- 
settled inhabitants, and the visitor sees only a few Arab tents 
and frail reed-huts, furnishing an impressive contrast to the 
ruins of the great walls and temples; the only trees now a 
few willows and tamarisks along the river, and here and there 
a spiny acacia scattered over the sand. 
Recent Changes in Area of Growth of Common 
Economic Plants. 
About the plants that have been cultivated for many 
centuries, such as the vine and the hop, the cereal grasses 
and the common fruits and timber trees of the north tem¬ 
perate zone, the farmers, gardeners, and foresters, who have 
been working at them for generations under every phase of 
growth and every modification of soil and climate know far 
more about their different varieties and the situations they 
need in order to be grown successfully than botanists, whose 
attention is not concentrated upon the plants which are 
specially valuable from an economic point of view, which do 
not number more than perhaps one hundred species out of 
the one hundred thousand with which the botanist has to 
deal. But even of most of these during the last generation, 
as population has increased and the carrying trade has been 
completely revolutionised by steam and electricity, the 
countries in which they are grown have been changed very 
materially. The total amount of foreign food imported into 
Great Britain in 1864 was an average of twenty-five shillings 
per head. In 1883 it amounted to sixty-nine shillings per 
head, the difference representing a lump sum of seventy-seven 
millions of pounds per annum. In 1864 the total amount of 
foreign grain and flour imported into the country was worth 
twenty millions of pounds sterling. In 1883 it cost seventy 
millions, an increase of fifty millions in twenty years. 
Before the war of secession in the United States, the 
Southern States had almost a monopoly of the trade in raw 
