I AM anxious to give in these lectures a statement, as clearly and as judicially as I can, of the discussions which have been going on since these results were published, to show what holes have been picked in the new views, and what new truths may be gathered from the new work which has now been brought to bear upon the old, so that as a result the place I have given to the sun among its fellow stars may be justified or withdrawn. These lectures will be different from the former ones, inasmuch as I then attempted to give you a piece of quiet history of several regions of fact and knowledge which had been well surveyed and mapped, and had become part and parcel of the common property of mankind. But now I shall have, in considering the discussion, rather to take you with me into the forefront of those who are fighting the battles on the confines of the unknown. I have to bring you news from the front, something like that which we are promised to-morrow or the next day from Port Arthur. I have to show, how the battle is waging, who has lost, what positions have been occupied, and what things new and true and beautiful have been wrested from the unknown region; and I am the more anxious to do that because it enables me to bring before you the enormous advantages under which such work is now carried on; advantages in that now, when any question is put to any part of the heavens, we know that there are many good workers employed under the best possible conditions to get the particular information that we want; besides these advantages, in every branch of inquiry we find advances gigantic, marvellous, almost beyond belief.