An object may not only contain stars, but also nebulosity not composed of them. - William Herschel

Nebulæ can be selected so that an insensible gradation shall take place from a coarse cluster like the Pleiades down to a milky nebulosity like that in Orion, every intermediate step being represented. This tends to confirm the hypothesis that all are composed of stars more or less remote.

I compared it to H Geminorum and the small star in the quartile between Auriga and Gemini, and finding it so much larger than either of them, suspected it to be a comet.

In future... we shall look upon those regions into which we may now penetrate by means of such large telescopes, as a naturalist regards a rich extent of ground or chain of mountains containing strata variously inclined and directed, as well as consisting of very different materials. The surface of a globe or map therefore will but ill delineate the interior parts of the heavens.