. . . .
"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."