mented on by Prof. ZUNTZ. 11461

IX. SANITATION.--On Purification of Air by Ozone--with an Account
of a New Method.--By Dr. B. W. RICHARDSON.--A very important
subject treated in full, giving the past attempts in the
utilization of ozone and a method now available. 11460

X. TECHNOLOGY.--Alkali Manufactories.--Present aspect of the
Leblanc process and the new process for the recovery of
sulphur from its waste. 11457

Dried Wine Grapes.--The preparation of the above wine on a
large scale in California, with full details of the process
adopted. 11461

The Production of Ammonia from Coal.--By LUDWIG MOND.--A
valuable review of this important industry, with actual
working results obtained in carrying out a retort process.--2
illustrations. 11454

Nature, Composition, and Treatment of Animal and Vegetable
Fabrics.--The history of fabrics and fibers in the vegetable
and animal world, their sources, applications, and
treatments. 11453

Walnut Oil.--By Thomas T. P. BRUCE WARREN.--An excellent oil
for painters' use, with description of a simple method for
preparing it on a small scale. 11462

* * * * *

THE NAVAL FORGES AND STEEL WORKS AT ST. CHAMOND.

With the idyls and historic or picturesque subjects that the Universal
Exposition gives us the occasion to publish, we thought we would make
a happy contrast by selecting a subject of a different kind, by
presenting to our readers Mr. Layraud's fine picture, which represents
the gigantic power hammer used at the St. Chamond Forges and Steel
Works in the construction of our naval guns. By the side of the
machinery gallery and the Eiffel tower this gigantic apparatus is well
in its place.

[Illustration: UNIVERSAL EXPOSITION--BEAUX ARTS--MARINE IRON AND STEEL
WORKS AT SAINT CHAMOND--PRESENTATION OF A PIECE OF ORDNANCE UNDER THE
VERTICAL HAMMER.--PICTURE BY M. JOSEPH LAYRAUD.]

The following is the technical description that has been given to us
to accompany our engraving: In an immense hall, measuring 260 ft. in
length by 98 ft. in width, a gang of workmen has just taken from t