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GB675080A
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Apparatus for indicating percentage change in concentration of a solution
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GB675030A
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Apparatus for the measurement, and comparison, of the conductivity of solutions
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GB686681A
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Apparatus for measuring the conductivity of solutions
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GB649894A
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Improvements in and relating to electrical measuring instruments
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GB612155A
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Improvements in direct reading ph meters
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GB608188A
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Improvements relating to a.c. measuring instruments
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GB606707A
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An improved method of and apparatus for testing thermionic valves
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GB556467A
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Improvements in protective systems and apparatus for circuits utilising rectified orunrectified a.c.
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GB530221A
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A method of and apparatus for electrically indicating the use of seats or other apparatus
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GB525690A
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Improvements in and relating to electric measuring instruments
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GB524618A
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Improvements in counting or indicating devices
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GB480752A
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An improved method and apparatus for testing radio valves
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