 ,  ,  |
Voltmeter- Amperemeter R. Seifert & Co |
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Voltometer |
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Voltometer |
 ,  ,  ,  ,  |
Voltometer- Amperemeter |
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Vril contact breaker |
 ,  ,  ,  |
W.B. Nicoloson's apparatus for the determination of the Earth's magnetic field |
 ,  ,  ,  |
Water level |
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Water pump |
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Water turbine |
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Water turbine |
