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. 93 - On the Dark Plane which is formed over a Heated Wire in Dusty Air
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
In the course of his examination of atmospheric dust as rendered evident by a convergent beam from the electric arc, Professor Tyndall noticed the formation of streams of dust-free air rising from the summits of moderately heated solid bodies. “To study this effect a platinum wire was stretched across the beam, the two ends of the wire being connected with the two poles of a galvanic battery. To regulate the strength of the current a rheostat was placed in the circuit. Beginning with a feeble current, the temperature of the wire was gradually augmented; but before it reached the heat of ignition, a flat stream of air rose from it, which, when looked at edgeways, appeared darker and sharper than one of the blackest lines of Fraunhofer in the solar spectrum. Right and left of this dark vertical band the floating matter rose upwards, bounding definitely the non-luminous stream of air.”……
“When the wire is white hot, it sends up a band of intense darkness. This, I say, is due to the destruction of the floating matter. But even when its temperature does not exceed that of boiling water, the wire produces a dark ascending current. This, I say, is due to the distribution of the floating matter. Imagine the wire clasped by the mote-filled air. My idea is that it heats the air and lightens it, without in the same degree lightening the floating matter.
- Type
- Chapter
- Information
- Scientific Papers , pp. 151 - 154Publisher: Cambridge University PressPrint publication year: 2009First published in: 1900