he moons:

Naval Observatory, Washington, D.C.,
March 4th, 1878.

EDITOR ST. NICHOLAS: The periods (of revolution) of the satellites
of Mars are as follows,--Deimus being the outer satellite, and
Phobus the inner one:

Period of Deimus, 30 hours, 18 minutes, 0 seconds.
" " Phobus, 7 " 39 " 16 "

These values are very nearly correct, and will be changed in the
final calculation only a few seconds, if at all.--Yours truly,

A. HALL.

* * * * *

The following are extracts from the letters of a young girl now
traveling in Europe:

Berlin, 1877.

DEAR ST. NICHOLAS: We were in the Auer Cathedral, Munich, looking
down the long nave, when troops of little children, boys and girls,
each with a little knapsack strapped between the shoulders, leaving
the hands and arms free for play, came hastening in by twos and
threes, till the whole church seemed full. They all knelt down,
whispered a few words of prayer, and remained for a brief space,
silent and motionless, bowed down in devotion; then they quietly
arose and went out. I shall not soon forget Auer Cathedral with its
little worshipers.

We have been settled at Berlin for a month. Being the residence of
the Emperor and Court, it is very gay with balls, theaters, etc.,
and the streets are bright and lively with fine uniforms, prancing
horses, and carriages full of richly dressed ladies, their escorts
riding on horseback at the side. It presents a lively contrast with
Munich in these respects, but, as to sunlight, it is a gloomy
place. Thus far we have had only four pleasant days, and on those
the sun set between three and four in the afternoon. Some days we
thought it did not rise at all! We realize now, for the first time,
how far north Germany is.

We improved one of our pleasant days by a trip to Potsdam, where is
the summer palace of the kings of Prussia. Here are the rooms of
Frederick the Great, just as he arranged them. His library is
chiefly of French books, and fills the shelves, which are
everywhere, from floor to ceiling--upon the doors, even, so that,
when they are shut, one feels imprisoned in books!

At the opposite end of the palace are the rooms once occupied by
Voltaire. The walls are covered with painted wood carvings of cats,
dogs