_Father_--"William, speak kindly--tell your sister what this
instrument is, and what you want to do with it."

_William._--(Scientifically.)--"In war, when a besieged
garrison wishes to know all the movements of the enemy, without being
seen, they erect behind the walls, or the ramparts, a mirror, placed
at the end of a long pole, and inclining towards the country. You
understand, then, that everything that takes place outside, is
reflected in the mirror, and can be seen from within, or in another
mirror placed at the bottom of the pole, and sloping inwards. This,
Lucy, is what is called a polemoscope--that is to say, an instrument
for observations in war."

"Thank you, William," said Lucy, "but what are you going to do with
it?"

_William._--"The thing is quite plain. I am going to fasten a
small mirror on a light pitchfork, inclining it downwards. This
pitchfork I shall fasten firmly to pole; then some one will climb,
dear papa, without any danger, as far as the strong branches reach;
from thence he can draw up the pole and its mirror, with a long
string, and by raising the mirror above the nest, he will enable us
to see, with the aid of your telescope, all that the nest contains.
This is my plan, and I think it is not so bad!"

_Father_.--(Smiling.)--"Dear William. It is a great pity,
however, that you are so blind. There are two things you have not
considered. One is, that the branches which cover the nest, are very
thick and tufted. Therefore, your mirror, even if it reached their