Ekholm and one other male
assistant, besides a lady who does the telegraphic and some of the
computing work.
The main building contains a commodious office, with a small library
and living apartments for the assistant. The principal instrument room
is a separate pavilion in the garden. Here is located Thiorell's
meteograph, which records automatically every quarter of an hour on a
slip of paper the height of the barometer, and the readings of the wet
and dry thermometers. Another instrument records the direction and
velocity of the wind.
This meteograph of Thiorell's is a very remarkable instrument. Every
fifteen minutes an apparatus is let loose which causes three wires to
descend from rest till they are stopped by reaching the level of the
mercury in the different tubes. When contact is made with the surface
of the mercuries, an electric current passes and stops the descent of
each wire at the proper time. The downward motion of the three wires
has actuated three wheels, each of which carries a series of types on
its edge, to denote successive readings of its own instrument.
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