SCIENTIFIC AMERICAN

of great value and interest.

The Editors are assisted by many of the ablest American and European

Writers, and having access to all the leading Scientific and

Mechanical Journals of the world, the columns of the SCIENTIFIC

AMERICAN are constantly enriched with the choicest Information.

An Official List of all the Patents Issued is published Weekly.

The Yearly Numbers of the SCIENTIFIC AMERICAN make two splendid

Volumes of nearly ONE THOUSAND PAGES equivalent in size to FOUR

THOUSAND ordinary book pages.

Scientific American, Volume XXIV., No. 12, March 18, 1871 A Weekly Journal of Practical Information, Art, Science, Mechanics, Chemistry, and Manufactures. · 第 192 / 194 题