In alluding to the Nebulæ, as subjects of our most powerful telescopic observation, the Essayist speaks in a tone of sarcasm concerning the “_shining dots_,”—the “_lumps of light_” which are rendered apparent amidst them: asking, what are these lumps? (1.) How large? (2.) At what distances? (3.) Of what structure? (4.) Of what use?—adding, he must be a bold man who undertakes to answer the question, that each is a Sun, with attendant systems of planets. Sir David, exceedingly irate, says, “We accept the challenge, and appeal to our readers:”—(1.) The size of the dot, or lump, is large enough to be a Sun. (2.) He cannot answer this, for want of knowing ‘the apparent distance between the centres of the dots.’ (3.) Like our Sun—‘It will consist of a luminous envelope, enclosing a dark nucleus.’ (4.) Of no conceivable use, but to give light to planets, or to the solid _nuclei_ of which they consist. In his turn, he asks the Essayist—what is the size, distance, structure, and use of the dots, upon his hypothesis? The Essayist, he observes, is silent;[120] but in his Essay, he had said, distinctly enough, “Let us not wrangle about words. By all means let these dots be stars, if we know about what we are speaking: if a star mean, merely, a luminous dot in the sky. But that these stars shall resemble, in their nature, Stars of the First Magnitude, and that such stars shall resemble Our Sun, are surely very bold structures of assumption, to build on such a basis. Some nebulæ are resolvable into distinct points: but what would it amount to? That the substance of all nebulæ is not continuous; separate, and separable into distinct luminous elements:—nebulæ are, it would then seem, as it were of a curdled or granulated texture; they have run into _lumps_ of light, or been formed originally of such lumps.” And then follow some very ingenious and refined speculations, into which we have not space to enter; and indeed we may be well content with what we have done, having travelled from a tolerable depth in the crust of our own little planet, past planet after planet, star after star, till we reached the nebulous “outskirts of creation;” accompanied by two Mentors of Infinitude,—whispering into our ear—one, that life, animal, intellectual, moral, was swarming around us at every step; the other, that that life ceased with our own Earth, as far as we were able to detect its existence, and giving us very solemn and mysterious reasons why it should be so.