A New Industrial Age. Chapter 14. Part I - The Expansion of Industry. Before the 1860’s, the US was mostly agricultural. By the 1920’s, it was the most industrialized nation on Earth. How?. This was due to several factors… a wealth of natural resources government support for business
to today’s technology.
like carbon. iron – impurities = steel.
The device consisted of a coil of wire, a magnetic arm and a taut
membrane. Any sound caused the membrane, and hence the magnetic
arm, to vibrate. The movement of the magnet induced a fluctuating
electric current in the coil. This electrical signal could be reconverted
into sound by an identical apparatus at the other end of the circuit.