These arguments are based on the belief that Nature never makes a mistake; that she made the bird to fly, and therefore the bird must be the most perfect model for the successful flying machine. But the truth is, the bird was not made primarily to fly, any more than man was made to walk. Flying is an incident in the life of a bird, just as walking is an incident in the life of a man. Flying is simply a bird’s way of getting about from place to place, on business or on pleasure, as the case may be. Santos-Dumont, in his fascinating book, _My Air-Ships_, points out the folly of blindly following Nature by showing that logically such a procedure would compel us to build our locomotives on the plan of gigantic horses, with huge iron legs which would go galloping about the country in a ridiculously terrible fashion; and to construct our steamships on the plan of giant whales, with monstrous flapping fins and wildly lashing tails. Sir Hiram Maxim says something akin to this in his work, _Artificial and Natural Flight_: “It appears to me that there is nothing in Nature which is more efficient, or gets a better grip on the water, than a well-made screw propeller; and no doubt there would have been fish with screw propellers, providing Dame Nature could have made an animal in two pieces. It is very evident that no living creature could be made in two pieces, and two pieces are necessary if one part is stationary and the other revolves; however, the tails and fins very often approximate to the action of propeller blades; they turn first to the right and then to the left, producing a sculling effect which is practically the same. This argument might also be used against locomotives. In all Nature we do not find an animal travelling on wheels, but it is quite possible that a locomotive might be made that would walk on legs at the rate of two or three miles an hour. But locomotives with wheels are able to travel at least three times as fast as the fleetest animal with legs, and to continue doing so for many hours at a time, even when attached to a very heavy load. In order to build a flying machine with flapping wings, to exactly imitate birds, a very complicated system of levers, cams, cranks, etc., would have to be employed, and these of themselves would weigh more than the wings would be able to lift.” As with the man-contrived locomotive, so the perfected airship will be evolved from man’s understanding of the obstacles to his navigation of the air, and his overcoming of them by his inventive genius. This will not be in Nature’s way, but in man’s own way, and with cleverly designed machinery such as he has used to accomplish other seeming impossibilities. With the clearing up of wrong conceptions, the path will be open to more rapid and more enduring progress.