Abstract

SYNOPSIS

A thermopile consisting of 50 couples is made from 6Au-40Pd with 90Pt-10Rh wire 0.0016 inch in diameter, by electrically fusing the junctions. Alternate junctions are attached to, but electrically insulated from, two thin concentric copper rings. The inner ring has its upper surface painted black; the outer ring, white. Details of construction are given.

When exposed to solar radiation, the excess in temperature of the junctions attached to the blackened ring over those attached to the whitened ring produces an electric current, the voltage of which is very nearly proportional to the intensity of the solar radiation. With a solar radiation intensity of one gram-calory per minute per square centimeter of surface the current generated has a voltage of between 9 and 10 millivolts.

A Type RM Engelhard recording voltmeter is employed to obtain continuous records of the solar radiation intensity. A sample record and illustrations of the thermopile are given.

© 1923 Optical Society of America

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References

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  1. Knut. ÅngströmThe absolute determination of the radiation of heat with the electric compensation pyrheliometer, with examples of the application of the instrument. Astrophysical Journal, 9, pp. 332–346.
  2. G. G. Abbot, F. E. Fowle, and L. B. AldrichAnnals of the Astrophysical Observatory of the Smithsonian Institution. 4, pp. 65–76.
  3. C. DornoProgress in radiation measurements. Mo. Weather Rev., Oct.1922,  50, pp. 515–521.
    [Crossref]
  4. A. Ångström and C. DornoRegistration of the intensity of sun and diffused sky radiation. Monthly Weather Review, March, 1921,  49, pp. 135–138.
    [Crossref]
  5. loc. cit. p. 516.
  6. H. H. KimballNocturnal radiation measurements. M. W. R., Feb., 1918,  46, pp. 56–70.
    [Crossref]
  7. Dorno (loc cit. p. 517) refers to this same deterioriation of magnesium oxide with excended exposure.
  8. See Fig. 1. Marvin pyrheliometer and auxiliary apparatus. Mo. Weather Rev.Nov., 1919,  47, opp. p. 769.
  9. Eric R. MillerInternal reflection as a cause of error in the Callendar bolometric sunshine receiver. Monthly Weather Review, 43:264–266.

1922 (1)

C. DornoProgress in radiation measurements. Mo. Weather Rev., Oct.1922,  50, pp. 515–521.
[Crossref]

1921 (1)

A. Ångström and C. DornoRegistration of the intensity of sun and diffused sky radiation. Monthly Weather Review, March, 1921,  49, pp. 135–138.
[Crossref]

1919 (1)

See Fig. 1. Marvin pyrheliometer and auxiliary apparatus. Mo. Weather Rev.Nov., 1919,  47, opp. p. 769.

1918 (1)

H. H. KimballNocturnal radiation measurements. M. W. R., Feb., 1918,  46, pp. 56–70.
[Crossref]

Abbot, G. G.

G. G. Abbot, F. E. Fowle, and L. B. AldrichAnnals of the Astrophysical Observatory of the Smithsonian Institution. 4, pp. 65–76.

Aldrich, L. B.

G. G. Abbot, F. E. Fowle, and L. B. AldrichAnnals of the Astrophysical Observatory of the Smithsonian Institution. 4, pp. 65–76.

Ångström, A.

A. Ångström and C. DornoRegistration of the intensity of sun and diffused sky radiation. Monthly Weather Review, March, 1921,  49, pp. 135–138.
[Crossref]

Ångström, Knut.

Knut. ÅngströmThe absolute determination of the radiation of heat with the electric compensation pyrheliometer, with examples of the application of the instrument. Astrophysical Journal, 9, pp. 332–346.

Dorno,

Dorno (loc cit. p. 517) refers to this same deterioriation of magnesium oxide with excended exposure.

Dorno, C.

C. DornoProgress in radiation measurements. Mo. Weather Rev., Oct.1922,  50, pp. 515–521.
[Crossref]

A. Ångström and C. DornoRegistration of the intensity of sun and diffused sky radiation. Monthly Weather Review, March, 1921,  49, pp. 135–138.
[Crossref]

Fowle, F. E.

G. G. Abbot, F. E. Fowle, and L. B. AldrichAnnals of the Astrophysical Observatory of the Smithsonian Institution. 4, pp. 65–76.

Kimball, H. H.

H. H. KimballNocturnal radiation measurements. M. W. R., Feb., 1918,  46, pp. 56–70.
[Crossref]

Miller, Eric R.

Eric R. MillerInternal reflection as a cause of error in the Callendar bolometric sunshine receiver. Monthly Weather Review, 43:264–266.

M. W. R. (1)

H. H. KimballNocturnal radiation measurements. M. W. R., Feb., 1918,  46, pp. 56–70.
[Crossref]

Mo. Weather Rev. (2)

See Fig. 1. Marvin pyrheliometer and auxiliary apparatus. Mo. Weather Rev.Nov., 1919,  47, opp. p. 769.

C. DornoProgress in radiation measurements. Mo. Weather Rev., Oct.1922,  50, pp. 515–521.
[Crossref]

Monthly Weather Review (1)

A. Ångström and C. DornoRegistration of the intensity of sun and diffused sky radiation. Monthly Weather Review, March, 1921,  49, pp. 135–138.
[Crossref]

Other (5)

loc. cit. p. 516.

Knut. ÅngströmThe absolute determination of the radiation of heat with the electric compensation pyrheliometer, with examples of the application of the instrument. Astrophysical Journal, 9, pp. 332–346.

G. G. Abbot, F. E. Fowle, and L. B. AldrichAnnals of the Astrophysical Observatory of the Smithsonian Institution. 4, pp. 65–76.

Eric R. MillerInternal reflection as a cause of error in the Callendar bolometric sunshine receiver. Monthly Weather Review, 43:264–266.

Dorno (loc cit. p. 517) refers to this same deterioriation of magnesium oxide with excended exposure.

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Figures (4)

Fig. 1
Fig. 1

Details of thermopile.

Fig. 2
Fig. 2

Tool employed in fusing thermocouples.

Fig. 3
Fig. 3

Thermoelectric pyrheliometer.

Fig. 4
Fig. 4

Solar radiation record.

Tables (1)

Tables Icon

Table 1 Comparison of Thermopile No. 5, with Marvin Pyrheliometer No. 3

Equations (1)

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E = 32.975 t + .03881 t 2