Page:Popular Science Monthly Volume 5.djvu/282

268 Fig. 8 is a part of Rosse's drawing made with the six-foot telescope.

It will be seen that the number of small stars above and west of the trapezium is very small, but a reference to the original drawing would show that the nebula was traced very far away from the central star: we see from these facts that the famous Rosse telescope is surpassed by several other telescopes in definition, but its enormous surface, when in good condition, is a great light-gatherer, and a faint nebulosity is distinguished in it more easily than in most other instruments—Lassell's reflector, for example.

Bond, however, has surpassed, by the aid of the 15-inch refractor at Cambridge, the work of Lord Rosse's assistants in every way, even in regard to the very points for which the reflector was best fitted. We must, however, attribute this, in no small degree, to the skill and assiduity of Bond himself.

We have thus traced the history of the nebula of Orion, as developed by the telescope alone, from its discovery to the present time. This has been done only imperfectly, on account of the impossibility of presenting complete engravings of the drawings made by the different observers, to whose work reference has been made. Several other astronomers of note have worked on this subject—notably Lamont and Secchi—but the results of their telescopic work are included in the preceding account.

The necessary conclusions as to the resolvability and change of the nebula have been indicated, as well as the strong probability that the nebula and the stars in the neighborhood are physically connected, which inference is mainly drawn from the recession of the nebula spoken of by Herschel.

The progress of telescopic research is well shown by the additions made year by year to our knowledge of this beautiful object, and we have no reason to be ashamed of it. The spectroscope has been busy on this nebula, as with others; but of its work it is not our purpose to speak. The desideratum in the study of these faint objects seems to be the extension of photography to their delineation. Until that is accomplished, we may rest content with such work as Bond and Struve have left us.