112 CLASSICS OF MODERN SCIENCE 



When Dr. H. pursued these researches, he was in the situation of a 

 natural philosopher who follows the various species of animals and 

 insects from the height of their perfection down to the lowest ebb of 

 life; when, arriving at the vegetable kingdom, he can scarcely point 

 out to us the precise boundary where the animal ceases and the plant 

 begins ; and may even go so far as to suspect them not to be essentially 

 different. But recollecting himself, he compares, for instance, one 

 of the human species to a tree, and all doubt of the subject vanishes 

 before him. In the same manner we pass through gentle steps from 

 a coarse cluster of stars, such as the Pleiades, the Praeserpe, the milky 

 way, the cluster in the Crab, the nebula in Hercules, that near the 

 preceding hip of Bootis, the 17th, 38th, 41st of the 7th class of his 

 catalogues, the loth, 20th, 35th of the 6th class, the 33d, 48th, 213th 

 of the I St, the 12th, 150th, 756th of the 2d, and the i8th, 140th, 

 725th of the 3d, without any hesitation, till we find ourselves brought 

 to an object such as the nebula in Orion, where we are still inclined 

 to remain in the once adopted idea, of stars exceedingly remote, and 

 inconceivably crowded, as being the occasion of that remarkable 

 appearance. It seems, therefore, to require a more dissimilar object 

 to set us right again. A glance like that of the naturalist, who casts 

 his eye from the perfect animal to the perfect vegetable, is wanting 

 to remove the veil from the mind of the astronomer. The object 

 mentioned above is the phenomenon that was wanting for this pur- 

 pose. View, for instance, the 19th cluster of the 6th class, and 

 afterwards cast your eye on this cloudy star, and the result will be 

 no less decisive than that of the naturalist alluded to. Our judgment 

 will be, that the nebulosity about the star is not of a starry nature. 

 But that we may not be too precipitate in these new decisions, let 

 us enter more at large into the various grounds which induced us 

 formerly to surmise, that every visible object, in the extended and 

 distant heavens, was of the starry kind, and collate them with those 

 which now offer themselves for the contrary opinion. It has been 

 observed, on a former occasion, that all the smaller parts of other 

 great systems, such as the planets, their rings and satellites, the 

 comets, and such other bodies of the like nature as may belong to 

 them, can never be perceived by us, on account of the faintness of 

 light reflected from small opaque objects: in the present remarks, 

 therefore, all these are to be entirely set aside. 



