It's June 10, 1752, in a field just north of Philadelphia, Pennsylvania.

As a storm bruise in the dark clouds overhead, 22-year-old William Franklin strides toward

a wooden shed at the end of the field.

Walking briskly beside him is his father, 46-year-old Benjamin Franklin, who carries a ball of twine,

a metal key, and a kite, everything he needs to conduct his latest scientific experiment.

William takes the kite from his father and admires the craftsmanship. Unlike a common paper kite,

this one is made of silk, a more durable material, suitable for a flight through a thunderstorm.

And at the top of the kite, a small wooden cross holds a thin handkerchief in a foot-long pointed wire.

The elder Franklin wants to understand the nature of lightning and whether it's caused by

electricity.

His idea is that the electrical charge from the storm clouds will travel down the wire,

through the string, and into the metal key tied at the bottom of the line.

An experiment like this has never been tried before, and it could be dangerous.

But the Franklins are taking precautions.

Kite's handle is coated in ceiling wax,

and they plan to protect themselves from the storm by taking shelter inside the shed.

Reaching the far end of the field, William raises the kite against the growing wind.

His father grips the handle, tells him to let go, and the kite catches a

gust and lifts into the gray electric air. Franklin's take a position just inside the sheds open door.

William grips the top of the handle, his father at the bottom. A few minutes go by with nothing

happening. William hears his father begin to mutter and disappointment. Then suddenly,

the wind picks up and the sky is darkened further. The kite string becomes wet from the rain,

...