This is a transcript of the handwritten lab notes produced by
Tesla between June 1, 1899 and Jan. 7, 1900. The book gives the reader a day by day
account of the months which culminated Tesla's decade long investigation into the
fundamental principals of wireless propagation. His dedication to creating a refined
system was astounding, with daily progress being made until a high degree of satisfaction
was achieved. Following the work recorded here, Tesla returned to the East confident that
high quality wireless communications to any point on the globe could be achieved with the
equipment he had just perfected.
. . . investigation outside and
such use. The synchronized coil was wound in one instance around a drum
10" in diam. and about 4 feet high from the ground and carrying on
top a board for placing the box with the instruments and supporting a
light rod for air or capacity wire. In another form of apparatus the
synchronized coil was wound on drum of 2 foot diam. and 18" high,
which was supported on a tripod of photographic outfit. These two
connections illustrated in Diagrams 1. and 2. were found best suitable.
The small condenser around secondary s comprised only a few sheets of mica
and tinfoil sufficient to let the currents of a frequency of 50,000 per
sec. pass through easily.
Sept. 18, 1899
Experiments were resumed with all transformers in place, high speed break
and connection in multiple arc of West. Transformer. The object was to
further test the intensity of the vibrations produced particularly without
spark. The connection was as in diagram. It was though that in this
arrangement, which was dwelt upon before, the disturbances were produced
more economically than when using a spark discharge. The experiments fully
confirm this. In the tests the capacity of the two balls of 18" diam.
did not very materially derange the adjustment and period of the circuit.
This is to be expected; as for the secondary the capacity was far too
smaIl and on the other hand the independent vibration of the extra coil
could not be materially interfered with since the condenser formed by the
two balls and zinc plate allowed free passage of currents to earth. Now
the important thing was to decide whether it is better to make length of
extra coil one half or one quarter of wave as before. This to be
thoroughly investigated. The working was excellent with 1/4 wave length.