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2. The terms “strong light”, “bright light” and “ordinary light” mean lights of intensities conforming intensities according to the provisions of referred to in Annex 5 to these regulations;

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6. The term “three-tone signal” means a signal repeated three times, of three blasts of different pitch with no interval between them lasting about two seconds in all. The frequency of the blasts shall be within the range 165 to 297 Hertz and the difference between the highest and the lowest blasts shall be at least two full notes. Each series of three blasts shall begin with the lowest and end with the highest note.

7. The term “peal of a bell” means two strokes of a bell.