t 35.8 "
Difference absorbed 5.64 "
Duty obtained, not including exciting machine 57 per cent.
Duty obtained, including exciting machine 48 "

During the various experiments the current traversing the line varied
from 7.59 amperes to 7.21 amperes. No heating of any kind was observed.

M.J. Bertrand, who communicated a paper to the Academy of Sciences on the
subject, commented on the relatively low speeds. It corresponds to a
linear displacement of the surface armatures, in no case exceeding the
speed of a locomotive wheel. The tension reached 5,500 volts., under very
satisfactory mechanical conditions, and with a current that in no way
endangered the line. This first experiment is certainly encouraging, and
it will be followed by others of a more complete and exhaustive
character. MM. De Rothschild are now embodying a powerful commission of
French and foreign scientists who will follow the subject carefully, and
report upon it. It may be safely predicted that one result of this action
will be the development of a new series of observations of the highest
technical interest and value.--_Engineering._

* * * * *

THE LOCKED AND CORDED BOX TRICK.

The trick with the locked and corded box, I believe, is an old one,
though perhaps not in its present form. In late years it has been revived
with improvements, and popularized by those clever illusionists, Messrs.
Maskelyne & Cook and Dr. Lynn, at the Egyptian Hall. There are several
ways of working the trick or, rather, of arranging the special bit of
mechanism wherein the peculiar features of the box consist. The one I am
about to describe is, I think, the best of those I am acquainted with, or
at liberty to divulge. Indeed, I don't know that any method is better,
and this one has the advantage over most others of allowing the performer
to get into as well as out of the box, without leaving a trace of his
means of ingress. It will be seen the box is paneled, and all the panels
look equally firm and fixed. As a matter of fact, one of the panels is
movable, though the closest scrutiny would fail to discover this if the
box and fittings are carefully made and adjusted. Fig. 1 shows the
general appearance of the box, of which the back is the same as the
front. In the box I describe, the end marked + has a movable panel. The
size of the box should be regulated by the size of the performer; but one