The bigger the rotor blades, the more energy they can capture from the wind. The giant blades (typically 70 m or 230 feet in diameter, which is about 30 times the wingspan of an eagle) multiply the wind's force like a wheel and axle, so even a gentle breeze is enough to make the outer edges of the blades turn around.he same thing happens in a wind turbine, only the dynamo generator is driven by the turbine's rotor blades instead of by a bicycle wheel, and the lamp is a light in someone's home dozens of miles away. Read more in our main article about generators.
The fur trade is a worldwide industry dealing in the acquisition and sale of animal fur. Since the establishment of a world fur market in the early modern period, furs of boreal, polar and cold temperate mammalian animals have been the most valued.
Trade, or commerce, involves the transfer of goods or services from one person or entity to another, often in exchange for money. A network that allows trade is called a market. The original form of trade, barter, saw the direct exchange of goods and services for other goods and services. Barter is trading things without the use of money. Later one side of the barter started to involve precious metals, which gained symbolic as well as practical importance.