Alexander Wilson used a kite for a meteorological experiments
in Scotland. Wilson attached thermometers to a number of kites
in a train flown from a common line. He was able to detect variations
of temperature at different altitudes. He flew his kites as high
as 3,000 feet.
In June 1752
Benjamin Franklin flew a kite in order to prove that lightning
was the same 'electrical matter' as generated electricity. Franklin
made a kite from silk with a cedar structure in the shape of a
cross. He realised that the kite would need to be made from silk
instead of paper in order to resist the rain and wind. The kite
had a tail, loop and string.
It also had
a very sharp pointed wire, of a foot in length, rising from the
front of the kite. At the end of the twine next to the handle
Franklin attached a piece of silk, which was tied to a metal key.
In his instructions
on how to repeat the experiment Franklin states that the person
holding the handle must stand underneath shelter to protect the
piece of silk from the rain. He even suggested that it was important
that the twine does not touch the frame of the shelter.
how the experiment should work. He understood that the electrical
charge, striking the wire sent a current down the twine making
it electrically charged. The loose filaments of twine would stand
out all along the length and could be attracted towards a finger
if placed near it. Once the rain wet the kite and the line, electrical
current flowed freely. The proof of this was in the key. Franklin
suggested that the electrical current could be felt if a knuckle
of a hand was placed near it.
The key could
be used to light kindling as it generated heat. Electrical experiments
could be experimented using the electrically charged key. These
experiments were usually conducted with a rubbed glass globe or
attempted the experiment but because they used paper kites and
heavy wires they were only able to gain heights of a 1000 feet.