Longitude2000

Sir Edmund Halley:
Don't touch that, boy!

William Harrison:
I didn't, sir, honest, I was just looking.

Sir Edmund Halley:
Do you know what that is?

William Harrison:
To tell the movements of the stars.

Sir Edmund Halley:
How do you know that?

William Harrison:
It's my job at home.

Sir Edmund Halley:
You have one of these at home!?

William Harrison:
No, sir, we use Mr. Johnson next door's chimney.

Sir Edmund Halley:
And, pray, what is it that you learn from Mr. Johnson next door's chimney?

William Harrison:
The time.

Sir Edmund Halley:
How can you tell the time with a chimney?

William Harrison:
If you stand in the right place, you can see Sirius.

Sir Edmund Halley:
Sirius?

William Harrison:
It moves behind Mr. Johnso's chimney 3 minutes and 56 seconds earlier every day. We need the time for our timepiece, to tell if it's true.

Sir Edmund Halley:
And is it?

William Harrison:
It's bloody perfect, sir.