Oscillograph records of speech (Rankin Kennedy, Electrical Installations, Vol II, 1909).jpg
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Oscillograph records of speech (Rankin Kennedy, Electrical Installations, Vol II, 1909), Oscillographs, Scans from 'Rankin Kennedy, Electrical Installations, Vol II', 1909, Scans from 'Rankin Kennedy, Electrical Installations, Vol II', 1903/undescribed
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演説録録
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oscillograph rankin electrical work electrical