Eagle River review. [volume] (Eagle River, Wis.) 1890-1927, 1914-07-31

The maximum tides in these pipes did not ex-
coed one-thousandth Of an inch; but so perfect
was the apparatus and accurate the readings
by Professor Nicholson that all the variations in
the tides were accurately determined. Tides are
complex things. Their height varies with the
position and distance of both the sun and the
moon and, therefore, is never the same two days
in succession.
Professor Michelsons experiments revealed 30
Of these variations. which correspondent almost
exactly with the variations obtained theoretically
by computing the variations in the attractive
forces exerted by the and the moon. The
practical correspondence of the actual height OF
the tides with the theoretical height proved that
the earth through and through is as rigid steel
and that it yields to outside forces as perfectly
elastic body and not viscous mass
This experiment reveals the Imagination and
the striking originality of Professor Nicholson.
The II st achievement to bring his name to the
attention of the scientific world was his accurate
determination Of the velocity of light, accom-
plished also after overcoming tremendous expert
mental difficulties Light is the fastest thing IN
nature; it represents the absolute limit of speed.
After four years of work and study, Professor
Nicholson announced that light travels with
velocity of 1s6.33O miles per second. The maxi
error in this figure does not exceed one
fortieth of one per cent
On the subject of spectrum analysis, Professor
Nicholson has devoted many OF the best years Of
his life. Spectrum analyses obtained by
means of the spectroscope. Every substance
when heated emits a characteristic light BY
means Of the spectroscope this light is analysed
and the elements giving of the light are thereby
revealed The spectroscope has enabled SCI
entists to determine the elements in far distant
stars. It has made possible tremendously impor-
tant discoveries concerning the nature of atoms,
the minute particles Of which all matter is COM
posed
The difficulties Of spectrum analysis will be
realized when it Is learned that a single atom OF
sodium emits 8O0,O0O00O,O00 vibrations per sec
ond of two slightly different kinds Of light Pro-
lessor Nicholson engaged in spectrum
analysis very long before he improved the spec
troscope, calling the improved type echelon
spectroscope. This wonderful machine divides
light into its various constituents and makes pos
sible their separate analysis.
The echelon spectroscope uses a glass grating
Ia piece of highly polished glass on which is
ruled from Is 600 to $4,000 straight equally spaced
lines to the inch. To make these gratings Pro
lessor Nicholson invented ruling engine that is
the most accurately constructed mechanical de-
vice in the world. It is operated in room the
temperature OF which is kept constant to within
one-hundredth of degree.
To assist In analyzing the lines of the spectrum
into their fundamental constituents, Professor
machine as complicated and as delicate as the
linotype machine. By It's use assistant can IN
q few minutes make calculations that would take
q skilled computer weeks to accomplish
Scientists have long endeavored to determine
the absolute motion Of the earth through space
II is known that the earth swings around the sun