direction and at any angle to the surface. For this purpose I placed
five smaller bars, passing through the roof and four sides, connected,
like the main conductor, with the receptacle or apergion, but so that
they could revolve through a much larger angle, and could at any
moment be detached and insulated. My steering apparatus consisted of a
table in which were three large circles. The midmost and left hand of
these were occupied by accurately polished plane mirrors. The central
circle, or metacompass, was divided by three hundred and sixty fine
lines, radiating from the centre to the circumference, marking as many
different directions, each deviating by one degree of arc from the
next. This mirror was to receive through the lens in the roof the
image of the star towards which I was steering. While this remained
stationary in the centre all was well. When it moved along any one of
the lines, the vessel was obviously deviating from her course in the
opposite direction; and, to recover the right course, the repellent
force must be caused to drive her in the direction in which the image
had moved. To accomplish this, a helm was attached to the lower
division of the main conductor, by which the latter could be made to
move at will in any direction within the limit of its rotation.
Controlling this helm was, in the open or steering circle on the right
hand, a small knob to be moved exactly parallel to the deviation of
the star in the mirror of the metacompass. The left-hand circle, or
discometer, was divided by nineteen hundred and twenty concentric
circles, equidistant from each other. The outermost, about twice as
far from the centre as from the external edge of the mirror, was
exactly equal to the Sun's circumference when presenting the largest
disc he ever shows to an observer on Earth. Each inner circle
corresponded to a diameter reduced by one second. By means of a
vernier or eye-piece, the diameter of the Sun could be read off the
discometer, and from his diameter my distance could be accurately