es on Garment Dyeing.--The production of blacks on silk and
wool.--Formulas for mordants.

Studies in Pyrotechny.--II. Methods of Illumination.--Continuation
of this valuable treatise.--9 illustrations.

The "Sensim" Preparing Box.--New machine for treatment of
fiber.--An improvement on the ordinary gill box.--3 illustrations.

* * * * *

THE RETIRO VIADUCT.

We give engravings of the viaduct over the river Retiro, Brazil, our
illustrations being reproduced by permission from the Proceedings of the
Institution of Civil Engineers. In a "selected paper" contributed to the
volume of these proceedings just published, Mr. Jorge Rademaker Grunewald,
Memb. Inst. C.E., describes the work as follows:

[Illustration: VIADUCT OVER THE RETIRO, BRAZIL.]

This viaduct was constructed in the year 1875, according to designs
furnished by the author, for the purpose of passing the Dom Pedro Segundo
State Railway over the valley which forms the bed of the river Retiro, a
small confluent on the left bank of the river Parahybuna. It is 265
kilometers (165 miles) from Rio de Janeiro, and about 10 kilometers (6.4
miles) from the city of Juiz de Fora, in the province of Minas Geraes,
Brazil. It has a curve of 382 meters (1,253 ft.) radius, and a gradient of
1 in 83.3. Its total length is 109 meters (357 ft. 7 in.); width between
handrails, 4 meters (13 ft.); and greatest height above the bed of the
river, 20 meters (65 ft. 7 in.).

The viaduct is composed of seven semicircular arches, each end arch being
built of ashlar masonry, and of 6 meters (19 ft. 8 in.) diameter; five
intermediate arches, 15 meters (49 ft. 2 in.) in diameter, are of iron. The
four central piers are of iron erected on pillars of ashlar masonry. The
metallic part of this viaduct is 80 meters (262 ft. 6 in.) long, and is
constructed in the following manner: The arches, and the longitudinal
girders which they support, are made of two Barlow rails riveted together,
with an iron plate 1/2 inch thick placed between them. The spandrels are
formed of uprights and diagonals, the former being made of four
angle-irons, and the latter of one angle-iron. Each pair of arches,
longitudinal girders and uprights, is transversely 3 meters (9 ft. 10 in.)
from center to center, and is connected by cross and diagonal bracing. On
the top of the longitudinal girders are fixed cross pieces of single Barlow
rails, upon w