From Alan Gibb
Your reader’s comment on a chicken perch solution to London’s “swinging”
Millennium Bridge reminded me of something
(Feedback, 7 April).
In the early part of the 20th century, a number of isolated electric power
systems were set up in towns throughout New Zealand. In one of these, the local
authority responsible decided to utilise the “free” energy available at night
from the local hydro-based electricity scheme to run street lighting. However
there were numerous complaints about the forgetfulness of the official
“lamplighter”, as well as the switch-on and switch-off times being out of sync
with the vagaries of the weather and the seasons.
The young electrical engineer responsible for the operation of the plant was
asked to devise an automatic system to avoid the problems. His solution was to
go into his chicken house where he prised up the end of the roost and connected
a spring and an electrical switch to it. These were adjusted to switch on in the
evening when about half of his chickens had roosted as it got dark, and to
switch off in the morning when it got light. It worked perfectly whatever the
weather and season.
Porirua, New Zealand
