Sir David Brewster dare not venture to suggest that they are inhabited, or in any condition to become so, any more than meteoric stones, which modern science regards as masses of matter, moving, like the planets, in the celestial spaces, subject to the gravitating attraction of the Sun; the Earth encountering them occasionally, either striking directly upon them, or approaching to them so closely that they are drawn by the terrestrial attraction, first within the atmosphere, and afterwards to the earth’s surface.[68] Here our Essayist gives a thrust at his Pluralist opponent not to be parried, asking him why he shrunk from asserting the planetoids and meteoric stones to be inhabited? If it be because of their being found to be uninhabited, or of their smallness, then “the argument that they _are_ inhabited _because_ they are planets fails him.”[69] “There is, then,” says elsewhere the wary Essayist,[70] “a degree of smallness which makes you reject the supposition of inhabitants. But where does that degree of smallness begin? The surface of _Mars_ is only one-fourth that of the Earth. Moreover, if you allow all the planetoids to be uninhabited, those planets which you acknowledge to be probably uninhabited far outnumber those with regard to which even the most resolute Pluralist holds to be inhabited. The majority swells every year; the planetoids are now thirty. The fact of a planet being inhabited, then, is, at any rate, rather the exception than the rule; and therefore must be proved, in each case, by special evidence. Of such evidence I know not a trace!” We may add, also, that Dr Lardner, vouched by Sir David Brewster, as we shall soon see, to be a thoroughly competent witness, gives up the planetoids as seats of habitation for animal life.[71]