186

CONJECTURE.

bra ? And is not this consonant to that pro-perty of a spot mentioned in the first article;for would it not hence follow that every spot,having a nucleus, should also have an umbrasurrounding that nucleus, a natural accountbeing at the same time suggested, for the bound-ary betwixt the nucleus and umbra being alwaysdistinctly defined. Although we may never havea competent notion of the nature and qualitiesof this shining and resplendent substance, or ofthe means by which the excavations in it areformed ; we, however, discover in their produc-tion the agency of some mighty though unknowncause which is there often exerting itself. Al-though we manifestly behold its effects, yet themode of its operations may perhaps remain un-searchable. But if we were here to venture aconjecture, might we not suppose, that the lu-minous matter is so disturbed, and the excava-tions in it occasioned by the working of somesort of elastic vapour which is generated withinthe dark globe ? And might not this elasticprinciple by its expansion swell into such avolume, as to reach up to the surface of the lu-minous matter, which would thereby be separated