The Transit of Venus: By George Forbes

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Macmillan and Company, 1874 - Electronic book - 99 pages
This 1874 text contains descriptions of Venus as imagined by scientists of the time.
 

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Page 97 - These Primers are extremely simple and attractive, and thoroughly answer their purpose of just leading the young beginner up to the threshold of the long avenues in the Palace of Nature which these titles suggest.
Page 75 - De l'Isle, originally fixed upon the following stations : — Alexandria, Sandwich Islands, Rodriguez, Kerguelen's Island, and New Zealand. No alteration has been made in the choice of these stations. Supplementary ones have, however, been added. Thus at Kerguelen's Island there will be two expeditions : one at Christmas Harbour in the north, and the other in the south of the island. In the Sandwich Islands there will be three stations : one at Honolulu, a second on the island of Hawaii, and a third...
Page 46 - ... of a milligramme, he might have a larger percentage error. When we consider how extremely small an angle the solar parallax is, it is astonishing to find so great a concordance between the results of different methods. As to the cause of the phenomenon of the " black drop," Lalande ascribed it to irradiation. Irradiation is that curious phenomenon in virtue of which a star, or any bright object, appears larger than it really is. If a thin platinum wire be intensely heated by the passage of an...
Page 97 - They are wonderfully clear and lucid in their instruction, simple in style, and admirable in plan. "—EDUCATIONAL TIMES. CHEMISTRY — By HE RoscoE, FRS, Professor of Chemistry in Owens College, Manchester. With numerous Illustrations. iSmo. is. New Edition. With Questions. "A very model of perspicacity and accuracy.
Page 50 - Transit of Venus made at Greenwich, the following facts appear : — 1. It requires considerable experience for an observer to appreciate all the definite changes of appearance which occur. 2. When two observers describe a particular phase which they see, and determine to observe this phase together, the times recorded by each are generally accordant within a fraction of a second. 3. The successive phases of an ingress or egress appear to follow each other sometimes rapidly, at other times gradually...
Page 97 - PHYSICS. LESSONS IN ELEMENTARY PHYSICS. By "BALFOUR STEWART, FRS, Professor of Natural Philosophy in Owens College, Manchester. With numerous Illustrations and Chromoliths of the Spectra of the Sun, Stars, and Nebulae.
Page 6 - In this apprehension I coincide with the opinion of the astrologers, because it is confirmed by experience ; but in other respects I cannot help despising their more than puerile vanities.
Page 98 - Primers.) ELEMENTARY LESSONS IN LOGIC ; Deductive and Inductive, with copious Questions and Examples, and a Vocabulary of Logical Terms. New Edition. Fcap. 8vo.
Page 52 - ... of measurement. There are two ways of applying the photographic method. The first is the same as the heliometric method. For this purpose it is necessary to have one station in the north and another in the south. By the other method we do not determine the least distance between the sun and planet, but the actual position of the planet at each observation. In other words, we determine the distance of Venus's centre from the sun's centre, and also the angular distance measured from the north point...
Page 52 - This is due to photogiaphic irradiation. It has been found by Lord Linds"ay and Mr. AC Ranyard to be mainly due to the reflection of light from the back of the glass plate.* It can be almost entirely avoided by wetting the back of the plate, and placing black paper against it. There will still be probably a slight enlargement of the sun's diameter. This will not affect the relative positions of the centres of the sun and Venus : but it will render it extremely difficult to determine the unit of measurement....

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