IN COMMAND. 95

“ According to all I’ve been able to pick up on the
subject they were unknown in Europe until the end of
the twelfth century; but had been used in China and the
East, generally, before the Christian era. It is said that
the Emperor Hon-aug-ti made an instrument, three or
four thousand years ago, which would indicate the south.”

“T read somewhere that a knowledge of the compass
was brought to Europe by Marco Polo on his return from
Cathay,” Miss Dunham interrupted.

“Ves, I remember that account; but I have seen it
stated that instruments were known to have been used at
sea about the year 300. I wonder if the mariners in
those days were troubled by the variations of the needle
as much as we are now.”

“I should say not, for there was probably less iron
around. Have you seen the compass invented by Sir
William Thomson? By the way, is he a relative of
yours?”

“IT have seen his invention, which is a valuable one, and
am sorry to say that I can’t claim kinship. He spells his
name without a ‘p,’ which is a heinous offence in the eyes
of those who claim such a letter necessary.”

“In what way does his compass differ from the one we
are using?” ,

“ It would take me too long to explain, and I question
if it were possible, no matter how hard I might try. It
has several magnets suspended by silk cords, and is made
of aluminum. The variations cannot be as great with
his instrument, and more easily corrected.”