Humboldt Library of Science Volume 49

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1883 Excerpt: ...at eleven years, and calculating back from the minimum of spots in the year 1610, we get four years of minimum solar disturbance, 1599, 1588, 1577, and 1566. We should have obtained the same result if we had used the more exact period, eleven one-ninth years, and had taken 1610.8 for the epoch of least solar disturbance (1610.8 meaning about the middle of October, 1610). Thus the year 1567 was a year of few Sun-spots, probably, occupying almost exactly the same position in the Sun-spot period as the year 1878. Clavius's observation, then, is in favor of our theory. But another observation between Clavius's and Kepler's may here be noticed. Jensenius, who observed the eclipse of 1598 at Torgau in Ger many, noticed that, at the time of mid-totality, a bright light shone round the moon. On this occasion, remarks Gra-t, the phenomenon was generally supposed to arise from a defect in the totality of the eclipse, though Kepler strenuously contended that such an explanation was at variance with the relation between the values of the apparent diameters of the Sun and Moon as computed for the time of the eclipse by aid of the solar and lunar tables. The corona, then, must have resembled that seen by Clavius, and since the year 1598 must have been very near the time of fewest spots, this observation accords with the theory we are examining. The next observation is that made by Wyberd during the eclipse of 1652. Here, there is a difficulty arising from the strange way in which the Sun-spots behaved during the interval from 1645 to 1679. According to M. Wolf, whose investigation of the subject has been very close and searching, there was a maximum of Sun-spots in 1639 followed by a minimum in 1645, the usual interval of about six years having elapsed; but there ca...