Author Description

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. 1856 Excerpt:... 94, right ascension, 183 18', north polar distance 84 35', where they are of irregular size and condensation. In all those examples the components are joined together by the surrounding Debulosity, but in some cases the two nebulae are quite distinct, as in Fig. 95, right ascension 342 48', north polar distance 103 43'. In these cases, Herschel imagined he perceived symptoms of the gradual formation of a double star, the nebulous matter of which they are formed condensing towards two centres of attraction. It will appear from this that the nebula, properly so called, according to Herschel's ideas, were far from being such important objects as the clusters, the latter being great agglomerations of stars, the nebulae only the material of a single, or, at most, a double star. But it would be hazardous to say that any particular nebula was irresolvable. The gigantjc telescope of Lord Rosse has shown that many such, hitherto deemed of this nature, consist of innumerable stars, very different from the single individual star which Herschel thought it was probable it would finally become. The suppositions relative to this nebulous substance, which Herschel thought to be so plentifully scattered through space, and the changes which he surmised that it underwent in the course of time, led the celebrated astronomer Laplace to form a similar hypothesis on the formation of the solar system, and the progressive development of the bodies of which it is composed, from one single and primitive mass of nebulous matter. He supposed that the sun was originally included among the nebulae, which extended as far as the most distant planet, and was endowed with a rotatory motion round the centre; and that in the course of ages this gaseous substance became more condensed towards...