Ecru:
Continue the foregoing operation for blue by passing the goods through
a solution of prussiate of potash.
MOTION OF WAVES.--The progressive motion of a wave on the water
exactly corresponds in speed with that of a pendulum whose length is
equal to the breadth of the wave; the same law, gravity, governs both.
LIGHT OF THE SUN.--A photometric experiment of Huygens, resumed by
Wollaston, a short time before his death, teaches us that 20,000 stars
the same size as Sirius, the most brilliant in the firmament, would
need to be agglomerated to shed upon our globe a light equal to that
of the sun.
Land Cultivation in Japan.--The entire arable land of the Japanese
empire is officially put at only 11,215,000 acres; but it is so
fertile and thoroughly cultivated that it feeds a population of
37,000,000, about that of France. Rice is one of the principal crops,
and of this some 200,000,000 bushels are raised annually.
Old London Bridge.--As early as the year 978 there was a wooden bridge
where London bridge now stands. This was replaced by another in 1014,
and another in 1209. The present London bridge was erected in 1831,
and may be considered the oldest existing bridge over the river.
The Shortest Method of Removing Silver from Plated Ware Before
Replating.--Dip the article in nitric acid; this will remove the
silver.
A Formula for White Metal.--Copper, 69.8 parts; nickel, 19.8 parts;
zinc, 5.5 parts; cadmium, 4.7 parts. It takes a fine polish.
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