Curiously enough, there is a way of explaining how, or rather why, the notion was formed--not unlike the one just given--to be found in the third of Sir George B. Airy's lectures on Popular Astronomy, delivered at Ipswich several years before the final experiments were made at the Harton Colliery. In that lecture, while describing how the Greek Astronomers accounted for the motions of the sun and planets round the stationary earth, he says, "It does appear strange that any reasonable man could entertain such a theory as this. It is, however, certain that they did entertain such a notion; and there is one thing which seems to me to give something of a clue to it. In speaking to-day and yesterday of the faults of education, I said that we take things for granted without evidence; mankind in general adopts things instilled into them in early youth as truths, without sufficient examination; and I now add that philosophers are much influenced by the common belief of the common people." We can agree with Sir George B. Airy in his ideas about education, and now conclude by saying that he has given us a very clear and notable example of a theory being accepted very generally, without being thoroughly examined to the very end, and of how easy it is for such theories to be handed down to future generations for their admiration. CHAPTER II. PAGE 33 The moon cannot have even an imaginary rotation on its axis, but is generally believed to have. Quotations to prove this. 35 Proofs that there can be no rotation. The most confused assertion that there is rotation shown to be without foundations. 37 A gin horse does not rotate on its axis in its revolution. 38 A gin horse, or a substitute, driven instead of being a driver. 38 Results of the wooden horse being driven by the mill. 39 The same results produced by the revolution of the moon. Centrifugal force sufficient to drive air and water away from our side of the moon. 40 That force not sufficient to drive them away from its other side. 41 No one seems ever to have thought of centrifugal force in connection with air and water on the moon. 41 Near approach made by Hansen to this notion. 42 Far-fetched reasons given for the non-appearance of air and water. 44 The moon must have both on the far-off hemisphere. 44 Proofs of this deduced from its appearance at change. 45 Where the evidences of this may be seen if looked for at the right place. The centrifugal force shown to be insufficient to drive off even air, and less water, altogether from the moon. 47 The moon must have rotated on its axis at one period of its existence. 48 The want of polar compression no proof to the contrary. 48 Want of proper study gives rise to extravagant conceptions, jumping at conclusions, and formation of "curious theories."