…
“My boy!” came to me after a few seconds.
…
“We must know how far we are apart.”
…
“That is easy.”
…
“You have your chronometer?”
…
“Yes.”
…
“Well, take it. Pronounce my name, noting exactly the second when you speak. I will repeat it as soon as it shall come to me, and you will observe the exact moment when you get my answer.”
“Yes; and half the time between my call and your answer will exactly indicate that which my voice will take in coming to you.”
…
“Just so, my uncle.”
…
“Are you ready?”
…