Book contents
- Frontmatter
- PREFACE
- Contents
- ART. 79 On the Determination of the Ohm [B. A. Unit] in Absolute Measure
- ART. 80 Experiments to Determine the Value of the British Association Unit of Resistance in Absolute Measure
- ART. 81 On the Specific Resistance of Mercury
- ART. 82 The Use of Telescopes on Dark Nights
- ART. 83 On a New Form of Gas Battery
- ART. 84 Acoustical Observations. IV
- ART. 85 Further Observations upon Liquid Jets, in Continuation of those recorded in the Royal Society's ‘Proceedings’ for March and May, 1879
- ART. 86 Address to the Mathematical and Physical Science Section of the British Association
- ART. 87 On the Tension of Mercury Vapour at Common Temperatures
- ART. 88 On the Absolute Measurement of Electric Currents
- ART. 89 On the Duration of Free Electric Currents in an Infinite Conducting Cylinder
- ART. 90 On the Equilibrium of Liquid Conducting Masses charged with Electricity
- ART. 91 On an Instrument capable of Measuring the Intensity of Aerial Vibrations
- ART. 92 Comparison of Methods for the Determination of Resistances in Absolute Measure
- ART. 93 On the Dark Plane which is formed over a Heated Wire in Dusty Air
- ART. 94 Experiments, by the Method of Lorenz, for the Further Determination of the Absolute Value of the British Association Unit of Resistance, with an Appendix on the Determination of the Pitch of a Standard Tuning-Fork
- ART. 95 On the Mean Radius of Coils of Insulated Wire
- ART. 96 On the Invisibility of Small Objects in a Bad Light
- ART. 97 On Maintained Vibrations
- ART. 98 The Soaring of Birds
- ART. 99 Distribution of Energy in the Spectrum
- ART. 100 Investigation of the Character of the Equilibrium of an Incompressible Heavy Fluid of Variable Density
- ART. 101 On the Vibrations of a Cylindrical Vessel containing Liquid
- ART. 102 On the Crispations of Fluid resting upon a Vibrating Support
- ART. 103 On Porous Bodies in Relation to Sound
- ART. 104 Suggestions for Facilitating the Use of a Delicate Balance
- ART. 105 On the Imperfection of the Galvanometer as a Test of the Evanescence of a Transient Current
- ART. 106 On Laplace's Theory of Capillarity
- ART. 107 On the Measurement of Electric Currents
- ART. 108 On the Circulation of Air observed in Kundt's Tubes, and on some Allied Acoustical Problems
- ART. 109 The form of Standing Waves on the Surface of Running Water
- ART. 110 Acoustical Observations.—V
- ART. 111 On the Measurement of the Electrical Resistance between Two Neighbouring Points on a Conductor
- ART. 112 On the Electro-Chemical Equivalent of Silver, and on the Absolute Electromotive Force of Clark Cells
- ART. 113 Presidential Address
- ART. 114 A Lecture Experiment on Induction
- ART. 115 On Telephoning through a Cable
- ART. 116 On a Galvanometer with Twenty Wires
- ART. 117 On Clark's Standard Cells
- ART. 118 On the Constant of Magnetic Rotation of Light in Bisulphide of Carbon
- ART. 119 Optics
- ART. 120 Über die Methode der Dämpfung bei der Bestimmung des Ohms
- ART. 121 On the Theory of Illumination in a Fog
- ART. 122 A Monochromatic Telescope, with application to Photometry
- ART. 123 Self-induction in Relation to Certain Experiments of Mr Willoughby Smith and to the Determination of the Ohm
- ART. 124 Professor Tait's “Properties of Matter”
- ART. 125 A Theorem relating to the Time-Moduli of Dissipative Systems
- ART. 126 On the Accuracy of Focus necessary for Sensibly Perfect Definition
- ART. 127 On an Improved Apparatus for Christiansen's Experiment
- ART. 128 Optical Comparison of Methods for Observing Small Rotations
- ART. 129 On the Thermodynamic Efficiency of the Thermopile
- ART. 130 On Waves propagated along the Plane Surface of an Elastic Solid
- ART. 131 On Prof. Himstedt's Determination of the Ohm
- ART. 132 On the Clark Cell as a Standard of Electro-motive Force
- ART. 133 Testing Dynamos
- ART. 134 The Reaction upon the Driving-Point of a System executing Forced Harmonic Oscillations of Various Periods, with Applications to Electricity
- ART. 135 On the Self-Induction and Resistance of Straight Conductors
- ART. 136 On the Colours of Thin Plates
- ART. 137 Notes, chiefly Historical, on some Fundamental Propositions in Optics
- ART. 138 On the Intensity of Light Reflected from Certain Surfaces at Nearly Perpendicular Incidence
- ART. 139 Notes on Electricity and Magnetism. I. On the Energy of Magnetized Iron
- ART. 140 Notes on Electricity and Magnetism. II. The Self-Induction and Resistance of Compound Conductors
- ART. 141 Notes on Electricity and Magnetism.—III. On the Behaviour of Iron and Steel under the Operation of Feeble Magnetic Forces
ART. 107 - On the Measurement of Electric Currents
Published online by Cambridge University Press: 05 December 2011
Book contents
- Frontmatter
- PREFACE
- Contents
- ART. 79 On the Determination of the Ohm [B. A. Unit] in Absolute Measure
- ART. 80 Experiments to Determine the Value of the British Association Unit of Resistance in Absolute Measure
- ART. 81 On the Specific Resistance of Mercury
- ART. 82 The Use of Telescopes on Dark Nights
- ART. 83 On a New Form of Gas Battery
- ART. 84 Acoustical Observations. IV
- ART. 85 Further Observations upon Liquid Jets, in Continuation of those recorded in the Royal Society's ‘Proceedings’ for March and May, 1879
- ART. 86 Address to the Mathematical and Physical Science Section of the British Association
- ART. 87 On the Tension of Mercury Vapour at Common Temperatures
- ART. 88 On the Absolute Measurement of Electric Currents
- ART. 89 On the Duration of Free Electric Currents in an Infinite Conducting Cylinder
- ART. 90 On the Equilibrium of Liquid Conducting Masses charged with Electricity
- ART. 91 On an Instrument capable of Measuring the Intensity of Aerial Vibrations
- ART. 92 Comparison of Methods for the Determination of Resistances in Absolute Measure
- ART. 93 On the Dark Plane which is formed over a Heated Wire in Dusty Air
- ART. 94 Experiments, by the Method of Lorenz, for the Further Determination of the Absolute Value of the British Association Unit of Resistance, with an Appendix on the Determination of the Pitch of a Standard Tuning-Fork
- ART. 95 On the Mean Radius of Coils of Insulated Wire
- ART. 96 On the Invisibility of Small Objects in a Bad Light
- ART. 97 On Maintained Vibrations
- ART. 98 The Soaring of Birds
- ART. 99 Distribution of Energy in the Spectrum
- ART. 100 Investigation of the Character of the Equilibrium of an Incompressible Heavy Fluid of Variable Density
- ART. 101 On the Vibrations of a Cylindrical Vessel containing Liquid
- ART. 102 On the Crispations of Fluid resting upon a Vibrating Support
- ART. 103 On Porous Bodies in Relation to Sound
- ART. 104 Suggestions for Facilitating the Use of a Delicate Balance
- ART. 105 On the Imperfection of the Galvanometer as a Test of the Evanescence of a Transient Current
- ART. 106 On Laplace's Theory of Capillarity
- ART. 107 On the Measurement of Electric Currents
- ART. 108 On the Circulation of Air observed in Kundt's Tubes, and on some Allied Acoustical Problems
- ART. 109 The form of Standing Waves on the Surface of Running Water
- ART. 110 Acoustical Observations.—V
- ART. 111 On the Measurement of the Electrical Resistance between Two Neighbouring Points on a Conductor
- ART. 112 On the Electro-Chemical Equivalent of Silver, and on the Absolute Electromotive Force of Clark Cells
- ART. 113 Presidential Address
- ART. 114 A Lecture Experiment on Induction
- ART. 115 On Telephoning through a Cable
- ART. 116 On a Galvanometer with Twenty Wires
- ART. 117 On Clark's Standard Cells
- ART. 118 On the Constant of Magnetic Rotation of Light in Bisulphide of Carbon
- ART. 119 Optics
- ART. 120 Über die Methode der Dämpfung bei der Bestimmung des Ohms
- ART. 121 On the Theory of Illumination in a Fog
- ART. 122 A Monochromatic Telescope, with application to Photometry
- ART. 123 Self-induction in Relation to Certain Experiments of Mr Willoughby Smith and to the Determination of the Ohm
- ART. 124 Professor Tait's “Properties of Matter”
- ART. 125 A Theorem relating to the Time-Moduli of Dissipative Systems
- ART. 126 On the Accuracy of Focus necessary for Sensibly Perfect Definition
- ART. 127 On an Improved Apparatus for Christiansen's Experiment
- ART. 128 Optical Comparison of Methods for Observing Small Rotations
- ART. 129 On the Thermodynamic Efficiency of the Thermopile
- ART. 130 On Waves propagated along the Plane Surface of an Elastic Solid
- ART. 131 On Prof. Himstedt's Determination of the Ohm
- ART. 132 On the Clark Cell as a Standard of Electro-motive Force
- ART. 133 Testing Dynamos
- ART. 134 The Reaction upon the Driving-Point of a System executing Forced Harmonic Oscillations of Various Periods, with Applications to Electricity
- ART. 135 On the Self-Induction and Resistance of Straight Conductors
- ART. 136 On the Colours of Thin Plates
- ART. 137 Notes, chiefly Historical, on some Fundamental Propositions in Optics
- ART. 138 On the Intensity of Light Reflected from Certain Surfaces at Nearly Perpendicular Incidence
- ART. 139 Notes on Electricity and Magnetism. I. On the Energy of Magnetized Iron
- ART. 140 Notes on Electricity and Magnetism. II. The Self-Induction and Resistance of Compound Conductors
- ART. 141 Notes on Electricity and Magnetism.—III. On the Behaviour of Iron and Steel under the Operation of Feeble Magnetic Forces
Summary
Perhaps the simplest way of measuring a current of moderate intensity, when once the electro-chemical equivalent of silver is known, is to determine the quantity of metal thrown down by the current in a given time in a silver voltameter. According to Kohlrausch the electro-chemical equivalent of silver is in c.g.s. measure 1·136 × 10−2, and according to Mascart 1·124 × 10−2. Experiments conducted in the Cavendish Laboratory during the past year by a method of current weighing described in the British Association Report for 1882 have led to a lower number, viz. 1·119 × 10−2. At this rate the silver deposited per ampere per hour is 4·028 grams, and the method of measurement founded upon this number may be used with good effect when the strength of the current ranges from ampere to perhaps 4 amperes. It requires however a pretty good balance, and some experience in chemical manipulation. [See Art. 112.]
Another method which gives good results and requires only apparatus familiar to the electrician, depends upon the use of a standard galvanic cell. The current from this cell is passed through a high resistance, such as 10,000 ohms, and a known fraction of the electro-motive force is taken by touching this circuit at definite points. The current to be measured is caused to flow along a strip of sheet German silver, from which two tongues project.
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- Scientific Papers , pp. 237 - 238Publisher: Cambridge University PressPrint publication year: 2009First published in: 1900