There are bumps, too, from sources other than these land shoals. Areas of cool air and warm disturb the flow of aerial rivers through which the plane moves. The “highs” and “lows” familiar to the meteorologists—the areas of high and low barometric pressure—are forever playing tag with each other, the air from one area flowing in upon the other much as water seeks its own level, creating fair weather and foul, and offering interesting problems to the students of avigation, not to mention variegated experiences to the flyer himself. The nautical boys have an advantage over the avigators. Constant things like the gulf stream can be labeled and put on charts and shoals marked. But one can’t fasten buoys in the atmosphere. Flyers can only plot topography. Air, like water, gives different effects under different conditions. The pilot must learn that when the wind blows over a hill from one direction, the result is not the same as that when it blows from another. Water behaves similarly. The shoals of the air seem a little more elusive, however, because their eddies are invisible. If one could see a downward current of air or a rough patch of it, avigating might be easier sometimes. “Bumpiness” means discomfort, or a good time for strong stomachs, in the air just as rough water does in ocean voyaging. There is no reason to suppose, however, if one isn’t susceptible to seasickness or car-sickness, that air travel will prove different. Some of the air-sickness experienced is due to the lack of proper ventilation in cabin planes. Many are not adequately ventilated for with the opening of the windows, the heat and sometimes the fumes of the motors are blown in. Adequate ventilation is one of the amenities which the plane of the future will have to possess. Perhaps the greatest joy of flying is the magnificent extent of the view. If the visibility is good, the passenger seems to see the whole world. I have spoken of the effect of height in flattening the landscape, always a phenomenon in the eyes of the air novitiate. Even mountains grow humble and a really rough terrain appears comparatively smooth. Trees look like bushes, and automobiles like flat-backed bugs. A second plane which may be flying a few hundred feet above the ground, as seen from a greater altitude looks as if it were just skimming the surface. All vertical measurement is fore-shortened. The world seen from the air is laid out in squares. Especially striking is the checkerboard effect wherever one looks down on what his brother man has done. Country or city, it is the same—only the rectangles are of different sizes. The city plays its game of checkers in smaller spaces than the country, and divides its area more minutely.