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changed so that the path of its shadow will pass farther north or south than before.

There are two series of eclipses remarkable for the long duration of the total phase. To one of these the eclipse of 1868, hereafter mentioned, belongs. This recurred in 1886, and will recur again in 1904. Unfortunately, at the first recurrence, the shadow was cast almost entirely on the Atlantic and Pacific Oceans, so that it was not favourable for observation by astronomers. That of 1904, September 9, will be yet more unfortunate for us, because the shadow will pass only over the Pacific Ocean. Possibly, however, it may touch some island where observations may be made. The recurrence of 1922, September 1, will be visible in northern Australia, where the duration of totality will be about four minutes.

To the other and yet more remarkable series belonged the eclipse of May 7, 1883, and that of May 11, 1901. At the successive recurrences of this eclipse the duration of totality will be longer and longer through the twentieth century. In 1937, 1955, and 1978 it will exceed seven minutes, so that so far as duration is concerned, our successors will see eclipses more remarkable than any their ancestors have enjoyed for many centuries.

About 1863-64 the spectroscope began to be applied to researches on the heavenly bodies. Mr. (now Sir William) Huggins, of London, was a pioneer in observing the spectra of the stars and nebulæ. For several years it did not seem that much was to be learned in this