POPULAR SCIENCE MONTHLY.
it. We have no evidence of definite space or time limits; quite the contrary. Every advance of knowledge only opens up new vistas into a remoter past and discloses further depths of immensity teeming with worlds."
Thus the truth urged against me is that we can not know anything about these ultimate physical principles in their application to the ultra-visible universe. But, unhappily for Professor Ward's criticism, I entered this same caveat long ago. Demurring to that doctrine of the dissipation of energy to which he now demurs, I wrote:—
"Here, indeed, we arrive at a barrier to our reasonings; since we can not know whether this condition is or is not fulfilled. If the ether which fills the interspaces of our Sidereal system has a limit somewhere beyond the outermost stars, then it is inferable that motion is not lost by radiation beyond this limit; and if so, the original degree of diffusion may be resumed. Or supposing the ethereal medium to have no such limit, yet, on the hypothesis of an unlimited space, containing, at certain intervals. Sidereal Systems like our own, it may be that the quantity of molecular motion radiated into the region occupied by our Sidereal System, is equal to that which our Sidereal System radiates; in which case the quantity of motion possessed by it, remaining undiminished, it may continue during unlimited time its alternate concentrations and diffusions. But if, on the other hand, throughout boundless space filled with ether, there exist no other Sidereal Systems subject to like changes, or if such other Sidereal Systems exist at more than a certain average distance from one another; then it seems an unavoidable conclusion that the quantity of motion possessed, must diminish by radiation; and that so, on each successive resumption of the nebulous form, the matter of our Sidereal System will occupy a less space; until it reaches either a state in which its concentrations and diffusions are relatively small, or a state of complete aggregation and rest. Since, however, we have no evidence showing the existence or non-existence of Sidereal Systems throughout remote space; and since, even had we such evidence, a legitimate conclusion could not be drawn from premises of which one element (unlimited space) is inconceivable; we must be forever without answer to this transcendent question." (First Principles, § 182, pp. 535-6.)
See, then, how the case stands. After urging against me the argument of "two eminent physicists" as fatal to my conclusions, he thereupon expresses dissent from the premises of that argument; and the reasons he gives for dissenting are like those given by me before he was out of his teens!
It is not always easy to disentangle misrepresentations; especially when they are woven into a fabric. For elucidation of this matter there needs another section. It may fitly begin with an analogy. An astronomer who "saw reason to think" that the swarm of November meteors this year would be greater than usual, would be surprised if the occurrence of a smaller number were