filling the box, and the same time for the preliminary lashing. It is
found, however, that three-quarters of a minute is sufficient for the
complete hooping of a bale.

[Illustration: COMPOUND HYDRAULIC PRESS. FIGS. 7 and 8.]

Figs. 7 and 8 show a similar press intended for jute pressing. This
has only one box, which is fixed, as the material has to be packed in
an orderly manner. Its speed is sixty bales an hour.--_Engineering._

* * * * *




JET PROPELLERS.--HYDRAULIC PROPULSION OF VESSELS.


Certain mechanical devices appear to exercise a remarkable influence
on some minds, and engineers are blamed for not adopting them, in no
very measured terms in some cases. It is not in any way necessary that
these devices should have been invented by the men who advocate their
adoption, in order to secure that advocacy. The intrinsic attractions
of the scheme suffice to evoke eulogy; and engineers sometimes find it
very difficult to make those who believe in such devices understand
that there are valid reasons standing in the way of their adoption.
One such device is hydraulic propulsion. A correspondent in a recent
impression suggested its immediate and extended use in yachts at all
events, and we willingly published his letter, because the system does
no doubt lend itself very freely to adoption for a particular class of