Annals of the Astrophysical Observatory of the Smithsonian Institution (1900)
Washington : Government printing office · leaf 187
rranged in average number recorded in 1947 was 151.6, a larger number groups of increasing sunspot numbers as shown in table 18. than in any year since 1778 when the average was 154.4. Figure 10 shows the relationship between solar-constant The next largest average was 139.1 in 1870. Thus the… … Figure io. — Sunspots versus solar constants, 1940 through 1950. 165
Infrared spectra · Solar radiation
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