That there is a portion of truth at the bottom of all this, we should be the last to deny. No respect is due to any employment of the intellect which does not tend to the good of mankind. It is precisely on a level with any idle amusement, and should be condemned as waste of time, if carried beyond the limit within which amusement is permissible. And whoever devotes powers of thought which could render to Humanity services it urgently needs, to speculations and studies which it could dispense with, is liable to the discredit attaching to a well-grounded suspicion of caring little for Humanity. But who can affirm positively of any speculations, guided by right scientific methods, on subjects really accessible to the human faculties, that they are incapable of being of any use? Nobody knows what knowledge will prove to be of use, and what is destined to be useless. The most that can be said is that some kinds are of more certain, and above all, of more present utility than others. How often the most important practical results have been the remote consequence of studies which no one would have expected to lead to them! Could the mathematicians, who, in the schools of Alexandria, investigated the properties of the ellipse, have foreseen that nearly two thousand years afterwards their speculations would explain the solar system, and a little later would enable ships safely to circumnavigate the earth? Even in M. Comte’s opinion, it is well for mankind that, in those early days, knowledge was thought worth pursuing for its own sake. Nor has the “foundation of Positivism,” we imagine, so far changed the conditions of human existence, that it should now be criminal to acquire, by observation and reasoning, a knowledge of the facts of the universe, leaving to posterity to find a use for it. Even in the last two or three years, has not the discovery of new metals, which may prove important even in the practical