approaches the single wind pipe and recedes from it. No matter how
slight this deviation is, every sound given by a single circle is heard
with periodical intensities which complicate the phenomenon. This
inconvenience could be avoided by placing several wind-pipes around the
circle; but while we can extend the period of the holes in two circles
(whose difference is 1) around the whole circle by blowing through a
single wind tube, we would be compelled to limit it to the distance
between two wind tubes, and it would become too short; for, when the
disk rotates with a velocity sufficient to produce notes high enough and
intense enough, the beats become too numerous to be easily perceived.

Besides these provisions, which sufficiently illustrate the points to
which we desire to call especial attention, Koenig also furnishes two
more disks.

The seventh contains 8 circles having 48, 54, 60, 64, 72, 80, 90, and
96 holes respectively. The 1st, 3d, 5th, and 8th will produce a perfect
chord when the air is admitted through the 11 holes in the wind chest;
with one wind tube the entire gamut may be obtained.

Finally the eighth disk contains 8 circles of holes, whose numbers are
in the ratio of 1:2:3:4, etc., and which may be used to illustrate
harmonics. C. F. K.

* * * * *




THE MOTIONS OF CAMPHOR UPON THE SURFACE OF WATER.