Lectures on astronomical theories . for retaining the theory or thevelocity of light ? It w^as notoriously suggested at firstto supply a cause for a particular effect; and it wasbased upon that but since it now appears that * To sum up the evidence and concisely state the conclusion towhich it has conducted .we find that the so-called eclipses referredto by Roemer (and by those who are supposed to have verified hisobservations) were the obscurations of the planet caused by the-occultations compounded with the eclipses (by the planets shadow.)And that the fact observed by him of
Lectures on astronomical theories . for retaining the theory or thevelocity of light ? It w^as notoriously suggested at firstto supply a cause for a particular effect; and it wasbased upon that but since it now appears that * To sum up the evidence and concisely state the conclusion towhich it has conducted .we find that the so-called eclipses referredto by Roemer (and by those who are supposed to have verified hisobservations) were the obscurations of the planet caused by the-occultations compounded with the eclipses (by the planets shadow.)And that the fact observed by him of the increasing lateness in th«commencement of the successive eclipses, as the earth receded to agreater distance from the planet, are due to the cause mentionedabove and illustrated in fig. 10, viz: variation in ihe angle of occul-tation, subject to which the occultation or compounded eclipse wasviewed, as tlie earth in its orbitad revolution receded from and agaiaadvanced towards the planet. 0 J f s a m f ^ o f e / / 5b«> 9^. VELOCITY-OF-LIGHT THEORY 41 that particular effect is claimed by another cause whichhas a primary right to there any other basisupon which the theory of the velocity of light may besupported ? We opine there is none other, and that thetheory must be pronounced untenable, because unsup-ported by fact. Plate 5, Fig. 5 and 6, may serve as a general represen-tation of the variation in the apparent scale on whicli thephenomena of the satellites eclipse and occultation takeplace, according to whether it is viewed by the terrestrialobserver from the earths most distant or least distantplace in its orbit. Fig. 8, which repeats a part of Fig. 6on a larger scale, illustrates more especially the usualcase of the eclipse compounded with the occultation. Inthis (Fig. 8.) it is evident that the angle subtended bythe arc contained between the outer edge of the shadowon the one side, and the visual ray touching the side ofthe planet on the other, is greate
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Keywords: ., bookcentury18, bookdecade1870, booksubjectastronomy, bookyear1876
