[Illustration: PLAN OF WORKS FOR CARBONIZING WOOL. (Scale 1-200.)]

The mode of work indicated here is called the moist process. It
necessitates the use of a solution of sulphuric acid, but, as this
latter destroys most colors, it cannot be used when it is desired to
preserve the tint of the woolen under treatment. In this case recourse
is had to the dry process, which consists in substituting the vapors of
nitric acid heated to 115° or 125° for the sulphuric acid. The
arrangement of the rooms must likewise be different. The chambers, which
may be in duplicate, as in the preceding case, are vaulted, and are
about three yards long by three wide and three high. The rags are put
into wire cages that have six divisions, and that are located in the
middle of the chamber, where they are slowly revolved by means of
gearings. Under the floor are the heating flues, and upon it is a
reservoir for holding the vessel that contains the acid to be vaporized.
The arrangements for the admission of air and carrying along the vapors
are the same as in the other case. Great precaution should be taken to
have the flues so constructed as to prevent fire.--_Bull, de la Musee de
l'Industrie_.

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APPARATUS FOR EVAPORATING ORGANIC LIQUIDS.


According to Mr. D'A. Bernard, it is especially important, in the dry
distillation of distiller's wash in a closed vessel, for the production