For three days this blinding headache lasted, and he suffered as
wild animals suffer, as it seemed the way on ship to suffer,
without plaint, without sympathy, utterly alone.

This morning, however, on entering his state-room to make the bed
and put things in order, I found him well and hard at work. Table
and bunk were littered with designs and calculations. On a large
transparent sheet, compass and square in hand, he was copying what
appeared to be a scale of some sort or other.

"Hello, Hump," he greeted me genially. "I'm just finishing the
finishing touches. Want to see it work?"

"But what is it?" I asked.

"A labour-saving device for mariners, navigation reduced to
kindergarten simplicity," he answered gaily. "From to-day a child
will be able to navigate a ship. No more long-winded calculations.
All you need is one star in the sky on a dirty night to know
instantly where you are. Look. I place the transparent scale on
this star-map, revolving the scale on the North Pole. On the scale
I've worked out the circles of altitude and the lines of bearing.
All I do is to put it on a star, revolve the scale till it is
opposite those figures on the map underneath, and presto! there you
are, the ship's precise location!"

There was a ring of triumph in his voice, and his eyes, clear blue
this morning as the sea, were sparkling with light.

"You must be well up in mathematics," I said. "Where did you go to