It is a far cry to the third new factor: Exploitation of the air. We were warned, by Sir Hiram Maxim about 1910 that a year or so of war would do more for the conquest of the air than many years of peace. It has. We hear of a man flying 260 miles in 90 minutes; of the Atlantic being flown in 24 hours; of airships which will have a lifting capacity of 300 tons; of air mail-routes all over the world. The time will perhaps come when we shall live in the air, and come down to earth on Sundays. I confess that, mechanically marvellous as all this is, it interests me chiefly as a prime instance of the way human beings prefer the shadow of existence to its substance. Granted that we speed up everything, that we annihilate space, that we increase the powers of trade, leave no point of the earth unsurveyed, and are able to perform air-stunts which people will pay five dollars apiece to see――how shall we have furthered human health, happiness, and virtue, speaking in the big sense of these words? It is an advantage, of course, to be able to carry food to a starving community in some desert; to rescue shipwrecked mariners; to have a letter from one’s wife four days sooner than one could otherwise; and generally to save time in the swopping of our commodities and the journeys we make. But how does all this help human beings to inner contentment of spirit, and health of body? Did the arrival of motor-cars, bicycles, telephones, trains, and steamships do much for them in that line? Anything which serves to stretch human capabilities to the utmost, would help human happiness, if each new mechanical activity, each new human toy as it were, did not so run away with our sense of proportion as to debauch our energies. A man, for instance, takes to motoring, who used to ride or walk; it becomes a passion with him, so that he now never rides or walks――and his calves become flabby and his liver enlarged. A man puts a telephone into his house to save time and trouble, and is straightway a slave to the tinkle of its bell. The few human activities in themselves and of themselves pure good are just eating, drinking, sleeping, and the affections――in moderation; the inhaling of pure air, exercise in most of its forms, and interesting creative work――in moderation; the study and contemplation of the arts and Nature――in moderation; thinking of others and not thinking of yourself――in moderation; doing kind acts and thinking kind thoughts. All the rest seems to be what the prophet had in mind when he said: ‘Vanity, vanity, all is vanity!’ Ah! but the one great activity――adventure and the craving for sensation! It is that for which the human being really lives, and all his restless activity is caused by the desire for it. True; yet adventure and sensation without rhyme or reason lead to disharmony and disproportion. We may take civilisation to the South Sea Islands, but it would be better to leave the islanders naked and healthy than to improve them with