At the shore station,
there is placed in deviation a galvanoscope, K, whose needle is
deflected. It suffices, then, to take datum points upon the
registering apparatus, upon the wheel, T, and the screw, a, in such
a way as to ascertain the moment at which the stylet, g, is going to
mark 3 meters. At this moment the circuit of the galvanoscope, K, is
closed, and we ascertain whether there is a deviation of the needle.
As the sea generally rises to the height of 3 meters twice a day, it
is possible to control the apparatus twice a day, and this is fully
sufficient.
It always belongs to practice to judge of an invention. Mr. Von
Hefner-Alteneck tells us that two of these apparatus have been set
up--one of them a year ago in the port of Kiel, and the other more
recently at the Isle of Wangeroog in the North Sea--and that both have
behaved excellently since the very first day of their installation. We
shall add nothing to this, since it is evidently the best eulogium
that can be accorded them.--_La Lumiere Electrique.
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