"One: There is a low limit of weight [of about] 50 pounds beyond which it is impossible for an animal to fly. Two: The animal machine is far more effective than any we can hope to make. Three: The weight of any machine constructed for flying, including fuel and engineer, cannot be less than three or four hundred pounds. Is it not demonstrated that a true flying machine, self-raising, self-sustaining, self-propelling, is physically impossible?"