Irwin 2-4
why build a bridge before levels of commerce
justified it? (p. 32)
- civic pride
- excitement of risk
- economical bridges were a point of pride--
Preservation:
- Henry David Thoreau:
questioned progress and argued for the value of un-managed
nature (published Walden in 1854)
- Frederick Law Olmsted wins the
competition to design Central Park in 1857: managed natural
surroundings will make people more moral and peaceful
- Yellowstone became the first
national park in 1872, protecting a special place from
development
- John Muir: set aside special
places, Yosemite became a state park in 1890 and then a
national park
- Adirondack Forest Preserve
(became a New York state park) 1885 to preserve forests and
water supply
- 1885 New York State
Reservation at Niagara Falls, taking privately owned land,
but how to restore a natural site while managing it for
tourists?
- Olmsted preferred peaceful to
awesome
- industrialization didn't raise
the same issues as tacky tourist attractions
- 1891 Forest Reserve Act
started the National Forest system
- 1916 National Park Service
created
Hydroelectric:
- In the industrial revolution individual
machines were powered from a central water wheel or steam
engine, connected by belts and shafts
- turbines (invented 1849) were more efficient
than waterwheels in using water power but hadn't been designed
for large amounts of water and a large drop
- electric arc lights were used commercially
from the 1870s but were very bright, better for outdoors
- Edison invented a system of incandescent
electric lights suitable for offices and homes, patented in
1879, using direct current
- but direct current motors were inefficient and
the electricity couldn't be transmitted very far
- Westinghouse
developed an alternating current (AC) lighting system in the
late 1880s, showed it off at the World Columbian Exposition
worlds fair, and licensed Tesla's patents for an efficient AC
motor, but the two AC systems were incompatible
- AC can be transmitted long distances (it is
easy to change the voltage and high voltage transmits with
less loss)
- factory use requires efficient polyphase
electric motors and allows a redesign of the factory when each
machine has its own motor
- Tesla's system was installed at Niagara by
Westinghouse because the system was to be oriented towards
factories, with transmission to Buffalo 25 miles away
