discoveries.

* * * * *

ELECTRICITY APPLIED TO THE MANUFACTURE OF VARNISH.

Messrs. Muethel & Luetche, of Berlin, recommend the following process for
the manufacture of varnish: The oils are treated by gases or gaseous
mixtures that have previously been submitted to the action of electric
discharges. The strongly oxidized oxygenated compounds that are formed
under such circumstances give rise, at a proper elevation of temperature,
to compounds less rich in oxygen, and the oxygen that is set free acts
upon the fatty acid that it is proposed to treat. A mixture of equal
parts of chlorine and steam may be very advantageously employed, as well
as anhydrous sulphuric acid and water, or oxygen, anhydrous sulphuric
acid and protoxide of nitrogen, nitrogen, oxygen, and hydrogen, protoxide
of nitrogen and air, or oxygen, and so on.

The apparatus is shown in section in the accompanying engraving; a is a
steam-pipe running from the boiler to the motor. From this pipe branch
conduits, b, that enter the vessels, B, in which the treatment is
effected, and that run spirally through the oil. At the lower part of the
vessel, B, there is tube wound into a flat spiral, and containing a large
number of exceedingly small apertures.

The oxidizing apparatus is shown at p. The gaseous mixture enters through
the tube, n, traverses the apparatus, p, and enters the vessel, B,
through the tubes, g and D. Fig. 2 gives the details of the oxidizing
apparatus, which consists of two concentric glass tubes, A and F,
soldered at x. A is closed beneath and held in a cylinder, C; F contains
a small aperture through which passes a tube, E. The gaseous mixture
enters through the latter, traverses the annular space between the tubes,
A and F, and then makes its exit through H, whence it goes to a similar
apparatus placed alongside of the other. The shaded parts of the
engraving represent bodies that are good conductors of electricity and
that communicate with the two poles of any electrice source whatever.

[Illustration: FIGS. 1 AND 2.]

The operation is as follows: After opening the tube, e, linseed oil is
introduced into the vessel, B, until the latter is half full, and, after
this, e is closed and the worm, S, is allowed to raise the temperature to
between 60 deg. and 80 deg.. Then the cock of the tube, d, which communicates
with an air pump, is opened, and the pressure is diminished to about 730
mm. of m