Stars, first observations of the, 4, 5, 6, 7; first maps of, 8; observations of Autolycus, Euclid, and Posidonius, 8, 10; first catalogues of, 19; latitude and longitude of, 24, 30; positions tabulated by Hipparchus, 30; Tycho Brahe’s catalogue and map of, 42, 44; stars in Gemini seen through a large telescope, 155; nebula of Orion, 157; Orion and its neighbourhood, 156; double, as defined by telescopes of different power, 162, 164, 167, 167; distance of stars from the earth, 159; facilities for observing Orion, its stars, a test for power of telescopes, 164; stellar photography, 172, 465, 466, 467, 478; their rising and setting as measurers of time, 176; double, measurement of, 359, 361, 362; spectrum of red star, 433 Star-clusters, double and multiple stars, 351 Star-spectra, from Father Secchi’s observations, 433; photographs of, 479 Star spectroscopes, at Cambridge (U.S.), 430; direct vision, 431 Star-time (_see_ Sidereal Time) Steinheil, improvement of specula, 117 Stellar day, 256 Stereographs of the moon, 465, 466 Sternberg, Tycho Brahe’s Observatory, 38 Stewart (Prof. Balfour), spectrum analysis, 402; solar photography, 471 Stokes (Prof.), experiments with phosphatic glass, 123; spectrum analysis, 402, 410 Stone, thermopile at Greenwich, 384 Strontium in the sun, 419 Struve, transit instrument, 285; double stars, 362; star magnitudes, 381 Sun, The; in Ptolemy’s system, 3; first determination of its yearly course, 8, 15; course in the zodiac, described by Autolycus, 9; altitude determined by the gnomon, 16, 18; and the Scarphie, 19, 20; telescopes for observing, 114; “mean sun,” 256; as a telescopic object, 349; presence of sodium in, 412, 415; vapour of other metals, 417; absorption spectrum, 418; telespectroscopic observations, 436; of the chromosphere, 437; sun-storms, 438, 439; photographs, 459, 469, 470 Sun-dials, 18 Sun-spots observed by Galileo and Scheiner, 78; examined by the position micrometer, 358; spectra of, 415, 435 Sunderland time signals, 278 T. Talcott, zenith telescope designed by, 285 Taurus, its position in the zodiac, 34 Telegraph wires, their application in determining “local time,” 281 TELEPOLARISCOPE, THE (Chap. XXX.), 441-453 Telespectroscope, 426 TELESCOPE, THE (Book II.), 55-172 TELESCOPE, THE EQUATORIAL (Book V.), 293-368