the North Star is; if you do not want to measure the
North Star, you may take any star when it is just to
north of you, and measure its height; wait twelve hours,
and if you can find it, measure its height again. Split
the difference, and that is the altitude of the pole, or
the latitude of you, the observer.

"Of course we know this," says the graduating world.
"Do you suppose that is what we borrow your book for, to
have you spell out your miserable elementary astronomy?"
At which rebuff I should shrink distressed, but that a
chorus of voices an octave higher comes up with, "Dear
Mr. Ingham, we are ever so much obliged to you; we did
not know it at all before, and you make it perfectly
clear."

Thank you, my dear, and you, and you. We will not
care what the others say. If you do understand it, or do
know it, it is more than Mr. Charles Reade knew, or he
would not have made his two lovers on the island guess at
their latitude, as they did. If they had either of them
been educated at a respectable academy for the Middle
Classes, they would have fared better.

Now about the longitude.

The latitude, which you have found, measures your
distance north or south from the equator or the pole. To
find your longitude, you want to find your distance
east or west from the meridian of Greenwich. Now, if any