Such about will be the coming flying-machine of the near future. The natural elements, so far from presenting barriers and obstacles, as they do to a great extent on land and ocean navigation, seem to be peculiarly inviting to ærostation. Previous to nearly every great discovery, difficulties have been thought to exist which its completion dissolved. In the days of stage-coaching, the expectations held out by those interested in steam transport were considered, even by most competent and intelligent men, as wholly chimerical; yet the locomotive far surpasses the race-horse in speed and endurance. When practice proved and datas could be fixed, that smooth tires met all the requirements on railroads--in place of cogwheels to gear into racks--how easy all calculations on adhesive force and friction then became. So with flight. XX.--WHAT THE CHANGES FOR THE BETTER WILL BE. It is impossible to overestimate the benefits which will accrue to mankind from such a creation. Flying will become a studied art, an amusement, an accomplishment, and inconvenience from sultry heat, or freezing cold, or deadly epidemics will no longer be suffered. Flying will become a business, a trade, and the advantages derived from it for industrial purposes will be wonderfully great. New channels of employment will be opened to thousands, yes, millions of starving fellow-beings. A new era will be inaugurated in history; and great as has been the destiny of our race, it will be quite outlustred by the grandeur and magnitude of coming events. Traveling at a speed of over one hundred miles an hour, distance will become comparatively annihilated. Cutting through the air from San Francisco to New York, for instance, in twenty-four hours, at one-sixth in cost and time; far safer, because of no irregulations nor obstructions of road, no snow-blockades or unnecessary delays; far cheaper, because of no great expense for outfit or maintenance, the ærial carriage will soon become the great means of travel throughout the world. The vast uninhabited but productive regions of this globe will be populated from overcrowded and impoverished communities, because of the extraordinary cheap, safe, and rapid travel by flying machines. New life will again be imparted to enterprise, speculation and labor; and lands will be cultivated and great cities be built in regions where the foot of human being has not trod for ages. The Andes and Rocky Mountains will become as familiar to us as the hills of our own city; and mining and other discoveries will follow each other with wonderful rapidity. The vexing and expensive explorations in the interiors of Africa and Australia, and towards the North Pole, will soon be brought to a speedy and satisfactory conclusion; and some of the wildest dreams of men be realized. XXI.--CONCLUDING REMARKS.