Then came another flash; and this time, with a tearing crack, a great stanchion of forked lightning snaked down the sky and struck close by the towers of Notre Dame. And as Thomas imagined the stone figures up there, staring out at the storm while the lightning crashed around them, their faces quite unmoved, he smiled to himself.

The storm was coming swiftly toward them now, over the rooftops, over the canals. Luc called out that they’d better seek shelter, but Thomas didn’t want to. Ever since he was a little boy, he had loved the electric excitement of thunderstorms. He didn’t know why. The rain began to pour down on them and Luc stood under the temple arches in a futile attempt to keep dry, but Thomas stayed where he was, standing on a slab of rock, letting the rain pound on his head. The rain was coming so hard that he couldn’t see the park below. The storm was directly above the park now. A huge bang shook the air as lightning struck a tree not a hundred paces away, but while Luc cringed, Thomas kept his feet planted, testing himself, proving that a poor young man in workman’s boots could dare the gods of the storm to strike him down, like a romantic hero.

Ten full minutes passed before the rain slackened a little and Thomas and Luc descended the hill and began their walk home. It was raining all the way, and Luc complained, but Thomas trudged firmly on, knowing that he must make a man of his brother.

So he was quite annoyed when, the next morning, he woke with a sore throat. By noon, he was shivering.

The illness of Thomas Gascon lasted many weeks. At first they thought it was the flu. Then they feared tuberculosis.

When pneumonia finally set in, and a fever racked his body, and he became delirious, the doctor told his parents that he might survive, because he was young and strong.

By November, he was past the worst; by December he was resting. But in January the doctor warned his parents that his lungs were compromised.

It was his father who found an answer: a charcuterie at the bottom of the hill of Montmartre, and run by a widow he knew, named Madame Michel, who had a daughter. It wasn’t a bad place. Unwillingly, Thomas worked there through the early months of 1887.

But he still dreamed of working on Monsieur Eiffel’s tower, and one February day, when the weather was mild and he had the afternoon off, he decided to go down to look at the site.