Lecture 9: Measurement Of Light And Radiation
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Source Metadata
Section titled “Source Metadata”| Field | Value |
|---|---|
| Source | Radiation, Light and Illumination |
| Year | 1909 |
| Section ID | radiation-light-and-illumination-lecture-09 |
| Location | lines 8511-9388 |
| Status | candidate |
| Word Count | 6669 |
| Equation Candidates In Section | 15 |
| Figure Candidates In Section | 6 |
| Quote Candidates In Section | 0 |
Opening Source Excerpt
Section titled “Opening Source Excerpt”LECTURE IX. MEASUREMENT OF LIGHT AND RADIATION. 74. Since radiation is energy, it can be measured as such by converting the energy of radiation into some other form of energy, as, for instance, into heat, and measuring the latter. Thus a beam of radiation may be measured by having it impinge on one contact of a thermo-couple, of which the other contact is maintained at constant temperature. A galvanom- eter in the circuit of this thermo-couple thus measures the voltage produced by the difference of temperature of the two contacts of the thermo-couple, and in this manner the temper- ature rise produced by the energy of the incident beam of radia- tion is observed. Probably the most sensitive method of measuring even very small amounts of radiation is the bolometer. The beam of the radiationSource-Located Theme Snippets
Section titled “Source-Located Theme Snippets”Radiation / light
Section titled “Radiation / light”LECTURE IX. MEASUREMENT OF LIGHT AND RADIATION. 74. Since radiation is energy, it can be measured as such by converting the energy of radiation into some other form of energy, as, for instance, into heat, and measuring the latter. Thus a beam of radiation may be measured by having it impinge on one conta ...Magnetism
Section titled “Magnetism”... AND RADIATION. 177 nometer, can be secured by using gray print on white back- ground, and lights of different colors thereby compared over a wide range of illuminations. With a luminometer chart of gray letters, of albedo a, on white background, the illumination or light flux density, at which the luminometer readings are made as described above, is: where i0 is the illumination or light flux density when using black print on white background. 81. Since light is a physiological effect, the measurement of this effect requires a physiological ...Waves / transmission lines
Section titled “Waves / transmission lines”... e temper- ature rise produced by the energy of the incident beam of radia- tion is observed. Probably the most sensitive method of measuring even very small amounts of radiation is the bolometer. The beam of the radiation (or after dissolving the beam into a spectrum, the wave length of which the power is to be measured) impinges upon a narrow and thin strip of metal, as platinum, and thereby raises its temperature by conversion of the radiation energy into heat. A rise of temperature, however, produces a rise of electric resistance, and the latte ...Ether references
Section titled “Ether references”... arts still much more from that of the tungsten lamp. Instead of amyl acetate, pentane has been used and is still used. It gives a somewhat whiter flame, but the pentane lamp is not as constant. However, the Hefner lamp, while universally used as pri- mary standard, is altogether too inconvenient for general pho- tometric use, and, for this purpose, usually incandescent lamps are employed which have been compared with, and standard- ized by, the Hefner lamp. In reality, from these standard incandescent lamps, by comparison, other incandescent lamps ...Chapter-Local Concept Hits
Section titled “Chapter-Local Concept Hits”| Concept Candidate | Hits In Section | Status |
|---|---|---|
| Light | 143 | seeded |
| Radiation | 70 | seeded |
| Illumination | 39 | seeded |
| Wave length | 8 | seeded |
| Photometry | 6 | seeded |
| Arc lamp | 5 | seeded |
| Spectrum | 5 | seeded |
| Ether | 2 | seeded |
| Light flux density | 2 | seeded |
Chapter-Local Glossary Hits
Section titled “Chapter-Local Glossary Hits”| Term Candidate | Hits In Section | Status |
|---|---|---|
| candle-power | 8 | seeded |
| wave length | 8 | seeded |
| flux of light | 6 | seeded |
| ether | 2 | seeded |
| light flux density | 2 | seeded |
| mechanical equivalent of light | 1 | seeded |
| ultra-red | 1 | seeded |
| ultra-violet | 1 | seeded |
Equation Candidates
Section titled “Equation Candidates”| Candidate ID | OCR / PDF-Text Candidate | Source Location |
|---|---|---|
radiation-light-and-illumination-eq-candidate-0276 | 74. Since radiation is energy, it can be measured as such | line 8514 |
radiation-light-and-illumination-eq-candidate-0277 | of resistance of 1 in a million and, with very sensitive measure- | line 8541 |
radiation-light-and-illumination-eq-candidate-0278 | 1 deg. cent, produces a resistance change of about 0.4 per cent, | line 8543 |
radiation-light-and-illumination-eq-candidate-0279 | logical effect exerted on the human eye by 5 sq. mm. of melting | line 8618 |
radiation-light-and-illumination-eq-candidate-0280 | as a calibrated or standardized 16-cp. incandescent lamp, and | line 8716 |
radiation-light-and-illumination-eq-candidate-0281 | L -T- S = x2 -T- 7/2, where x and y are the two distances of the | line 8720 |
radiation-light-and-illumination-eq-candidate-0282 | where i0 is the illumination or light flux density when using | line 9037 |
radiation-light-and-illumination-eq-candidate-0283 | 81. Since light is a physiological effect, the measurement of | line 9040 |
Figure Candidates
Section titled “Figure Candidates”| Candidate ID | OCR / PDF-Text Candidate | Source Location |
|---|---|---|
radiation-light-and-illumination-fig-055 | as shown diagrammatically in its simplest form in Fig. 55, the FIG. 55. two white screens A and B are illuminated, the one, A, by the light, L, which is to be tested, the other,… | line 8712 |
radiation-light-and-illumination-fig-057 | accuracy. FIG. 57. 78. When comparing lamps giving light of the same color, as incandescent lamps of the same filament temperature, that is, | line 8797 |
radiation-light-and-illumination-fig-058 | MEASUREMENT OF LIGHT AND RADIATION. 175 FIG. 58. the photometer may be used as far as it agrees with the lumi- | line 8928 |
radiation-light-and-illumination-fig-059 | Fig. 59, is the distribution curve in one meridian, it is the same FIG. 59. in every other meridian, and for photometric test of the illumi- nant it is sufficient to measure the… | line 9197 |
radiation-light-and-illumination-fig-060 | the former, giving a horizontal or equatorial distribution of FIG. 60. light intensity about as shown in Fig. 60. In this case the horizontal distribution curve may also be dete… | line 9242 |
radiation-light-and-illumination-fig-061 | side — minimum — intensity. Such curves are shown in Fig. 61. FIG. 61. This, however, carried out for every angle in the meridian, makes arc-light photometry rather laborious, e… | line 9306 |
Hidden-Gem Quote Candidates
Section titled “Hidden-Gem Quote Candidates”| Candidate ID | Candidate Passage | Source Location |
|---|---|---|
| No chapter-local candidates yet | - | - |
Modern Engineering Reading Prompts
Section titled “Modern Engineering Reading Prompts”- Radiation / light: Compare the chapter’s radiation vocabulary with modern electromagnetic radiation, spectral frequency, wavelength, absorption, and illumination engineering.
- Magnetism: Track flux, reluctance, permeability, magnetizing force, and loss language against modern magnetic-circuit terminology.
- Waves / transmission lines: Map Steinmetz’s wave and line language onto modern distributed constants, propagation velocity, standing waves, and reflections.
- Ether references: Verify exact wording before drawing conclusions. Ether language must be separated from later interpretive systems.
Ether-Field Interpretive Boundary
Section titled “Ether-Field Interpretive Boundary”- Radiation / light: Radiation and wave language can invite ether-field comparison, but source wording, modern radiation theory, and speculative synthesis must stay separated.
- Magnetism: Centrifugal/divergent magnetic-field readings are interpretive overlays, not automatic historical claims.
- Waves / transmission lines: Standing/traveling wave passages may support richer field interpretations; the page keeps those readings separate from verified Steinmetz wording.
- Ether references: If Steinmetz mentions ether, quote only the verified source words first; any broader ether-field synthesis belongs in a labeled interpretive layer.
Promotion Checklist
Section titled “Promotion Checklist”- Open the full source text and the scan or raw PDF.
- Verify the chapter boundary and surrounding context.
- Promote exact quotations only after checking the source image.
- Move mathematical candidates into canonical equation pages only after formula typography is corrected.
- Move diagram candidates into the diagram archive only after image extraction, crop verification, and manifest creation.
- Keep Steinmetz wording, modern translation, and ether-field interpretation in separate labeled layers.