The cotton-plant requires warmth, moisture, and a long season. It also thrives best near the sea. It grows better, on the whole, in subtropical rather than in tropical regions, and the difference is due probably to the longer days and higher temperature of the subtropical latitudes. In the United States the northern limit is approximately the thirty-eighth parallel. The seeds are planted, as a rule, during the first three weeks of April and the first two of May. The plants bloom about the middle of June; the boll or pod matures during July, and bursts about the first of August. The picking begins in August. [Illustration: COTTON IN THE UNITED STATES] The yield and the quality of the textile depend not only on conditions of the soil, but on locality. In the river flood-plains of the southern United States the yield is about two bales per acre; on the bluff lands it is but little more than one, unless unusual care is taken in the preparation of the land. The islands off the Carolina coast produce a very fine long-staple variety, commercially known as _sea island cotton_. A district in China produces a good fibre of brownish color known as _nankeen_, named for the city of Nanking, whence formerly it was exported. The valley of Piura River, Peru, produces varieties of long-staple cotton that in quality closely resemble silk. The fibre of ordinary American cotton is about seven-eighths of an inch long; it is made into the fabrics commercially known as "domestics" and "prints," or calico. If the fibre averages a little longer than the common grades it is reserved for canvas. Ordinary Peruvian cotton has a fibre nearly two inches long; it is used in the manufacture of hosiery and balbriggan underwear, and also to adulterate wool. The long-staple cotton of the Piura Valley is bought by British manufacturers at a high price, and used in the webbing of rubber tires and hose. Egyptian cotton is very fine and is used mainly in the manufacture of thread and the finer grades of balbriggan underwear. Sea island fibre is nearly two inches long and is used almost wholly in the making of thread and lace. The introduction of cotton cultivation resulted in very far-reaching consequences both from a political as well as an economic stand-point. The invention of the steam-engine by Watt gave England an enormous mechanical power. To utilize this the cotton industry was wrested from Hindustan; the mills were concentrated in Manchester and Lancashire; the cotton-fields were transferred to the United States. As a result, the plains of Hindustan were strewn with the bodies of starved weavers and spinners, but a great industry grew into existence in England. The invention of spinning machinery by Arkwright, Crompton, and Hargreaves, and the gradual improvement of the power-loom, greatly reduced the cost of making the cloth and, at the same time, enormously increased the demand for it. [Illustration: COTTON PRODUCTION]