It was observed that antennae were electrified during heavy snowfalls and that their potential reached to several thousands of volts at Mt. Teine. The electrification of the antennae was observed also during rainfalls at Sapporo. From further observations and experiments, it was concluded that the falling snow particles or rain drops play the part of an ion collector.

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Recently, with the increasing frequency ship-wrecks by the driftice on the North Pacific Ocean contained the Okhotsk Sea and the adjacent sea of Kurile Islands, the establishment of ice-area navigation has become a matter of urgent necessity.
For purpose to preserve these wrecks, it is intended in the present study to details a practical method to passage through ice-area over this sea-region, based on the lessons brought those shipwrecks and the experimences for many years of the navigators.
In chapter 2 details of the methods to foretell an existance of ice-area at outside of the field of vision, make use of the atmospheric phenomena (ice-blink, water-sky and mirrage of drift-ice, etc.), sea state, distribution of sea surface temperature and radar, etc.…
The practical method of ice-area navigation breaking through the ice-strips lied between the open waters, and the requisite measures in the case of beseted into very close ice-area (for example, quotating the exploding technics of hummocked ice-floes carried out at the entrance of Abashiri harbor in 1956) are discussed in chapter 3.
In chapter 4 mentions the counter-measures ought to take for ice-area navigation before the departure.
Finally, it is explained that the adoption of reconnaissance flight is very efficacy to ice-area navigation. (chapter 5)

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