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 presumable globes throughout space, we cannot entertain the supposition that any missile starting from one of them could ever fall down here. I have shown that meteorites cannot be reasonably associated with comets, notwithstanding the undoubted alliance which exists between comets and shooting-stars.

In the search for the body which must be credited with the parentage of the meteorite I have come at last to our own earth. It is true that difficulties have been urged against the view that meteorites have been derived from the globe on which we live. I have endeavoured to remove these difficulties, and I believe I have shown that they are, at all events, far less considerable than those which are experienced when we endeavour to attribute the meteorites to any other source that has been alleged. The objections that are felt to the view of the terrestrial origin of the objects are threefold. They are, firstly, the excessive initial velocity which would be required; secondly, the interference which the resistance of the air exposes to the passage of a meteorite from this globe to outer space; and, thirdly, the circumstance that meteorites do not resemble the more familiar substances recognised as belonging to terrestrial volcanoes. I do not think I am over sanguine in the belief that, serious as these difficulties may seem, they can be overcome.

In the first place, with regard to the initial velocity, I have pointed out that velocities, even one hundred times as great as that which we require, are at this moment occasionally imparted by explosive outbursts of the sun. Why, then, may not eruptions possessing one-hundredth part of the power of those which we see in the sun have taken place in our earth in primeval days,