This subject is one of great importance— an easy and safe mode for man to go through the air would be productive of immense changes in human society ; and who can doubt that those changes would be beneficial — Among them would probably come free trade, cheapness of food and clothing, extended geographical information, increased intercourse, and dissemination of knowledge, amelioration of all despotic influences,—a contraction, as it were, of the whole earth,—bring all men more fully into communion with each other, and thereby promoting the arts and sciences, and the cause ol freedom, with peaGe and good will among mankind. It may be that God has intended that man should never fly. Of this, however, we are very far from being sure : one thing is certain, which is, he never will fly unless he tries. Ten or a hundred unsuccessful attempts are insufficient to prove his inability so long as there isany reasonable ground on which to build a hope. As yet but little if any systematic or concerted effort ha? been made; now and then an individual, with small means perhaps, makes an experiment hut is soon discouraged. It may be he finds himselt on the wrong track, and gets no thm? but sneers and laughter for his pains Much, the largest portion of men deem it loll) to give the subject any serious thought; hu the present age has shown impossibilities to be both possible and practicable. Why may not our ideas change in regarii to flying? Lt all men who think that they have oi.e or more good thoughts relating to it publish the same; and if concerted measures, by means ol associate bodies or otherwise, are applied in good earnest, success is pretty sure to follow. Why may it not be accomplished in the present age i To make a beginning, the writer of this article will cheerfully submit a proposition of his own. For many years he has believed that balloons must be in part, if not altogether, dispensed with: their great bulk will always make them the sport of the winds. Ot dangerous and expensive materials, a bullet or a spark may easily destroy them, and the difficulty of alighting from them is very great. As something which may answer the purpose, an arrangement as follows is proposed : A Parachute of light and strong materials, made somewhat in the form of an open umbrella. The shaft which supports it to be firmly attached to the car or boat below; but in such a manner as to allow it to turn round easily without turning the boat. The machi-sery in the boat or car to give a rapid motion to the shaft, which, as it turns round, carries the Parachute around with it. Outside of the Parachute wings are to be firmly and immovably fixed, and braeai in meh manner w to cause it—the Parachute and all connected with it—to rise in the air whenever it is turned in the proper direction, with sufficient rapidity. The objects of the wings on the Parachute is merely to raise the apparatus and keep il suspended in the air. A few feet above the heads of the passengers, on each side of the car, are the propelling wings, fashioned, and somewhat like a single turn of a screw (many turns are worse than useless). By these propellers, which are supported from the car, and do not revolve around the shaft, the whole is made to go forward or backwards. In the engraving they are partly hid by the Parachute. The place for passengers may be a light car, or, as in the engraving, a boat. In mild weather the boat may alight and sail along upon the water, from which there would probably be but little difficulty in rising at pleasure. It may be advisable to place an oval screen or covei justabovethe passengers heads, and even to enclose them entirely or in part, to shield them from winds and the sight ot whirling motions. If left open on the sides such cover would also assist the Parachute In descending. The shaft should be a stout hollow tube, having a strong rope running through it, inside, from top to bottom, tense, and well tastened to it at each end, so that il the shaft at any time should break, the rope will still hold the Parachute and car together. The Parachute will let the car gently down to the earth if the machinery should stop, or the wings break. A hoop attached to it, inside, ot some little weight, will stiffen it, and alsoanswer the purposeofa fly-wheel. It may be braced, inside, somewhat like an umbrella, by supports so formed as to cut the air, and united firmly to the shaft at a point some distance down it, and just below that point a stout ring (in which the shaft must revolve, and which ring should bear upon an enlarged portion of the shafi),must be placed, from which ring stout rods should extend down to the sides of the boat or car. The boat being much the heaviest part of the apparatus, and firmly fixed below the centre, and parallel with the under part of the Parachute, it cannot upset while in the air. A slow revolu tion of the Paia-.hute would let the car gently down. Some kinds of springs, if desirable, may be fitted to the bottom of the car or boat, so as to ease the jar of alighting. All onoe fairly up in the air, the Parachute would not require a continuance of very rapid motion, because the propelling wings, by their horizontal action, would help to sustain it, particularly when the rudder or tail caused the stern of the boat to be slightly lower than the lorward part. Experience must show the proportionate tizesof the different parts, nd also the best form, number, and position of the wings. The wings must force the air against the surrounding air, and not against any part of the apparatus, as that would injure the desired effect; and, where many are used, do not let all play in the same circle The larger the circle or sweep of the wings, the less rapidity of the shaft is required. II on trial the car is found inclined to a revolving motion a long tail or rudder will probably prevent it. If not, many Parachutes, with their wings, may be placed along the car all worked by the same machinery. This will no doubt prevent such revolving motion, U any; but such arrangement lor a perfectly safe balancing of the car is not so good as when but a single Parachute is used. Now the question is, what power shall be applied? Is there any motive power having in itself sufficient force and durability and yet not requiring too heavy materials to give it life and application ? Experiment must decide this. If no such power is known who will find one? Possibly a crank, with proper gearing, in the hands of a man of good muscular strength, may be sufficient to enable one person thus to fly for a short distance. Use cogwheels for the main shaft, bands and pulleys for the side propellers. The writer has strong belief in the feasibility of this proposition, and would, with pleasure prosecute the subject further if it were not rather inconsistent with his other duties. He has only considered it as a leisure-hour amusement, hoping for useful results; and, being unwilling to cover the invention with let-ten Patent, though it original with himself he opens it to others, and all men are freely at liberty to make and use it if they please. May we not reasonably expect to be able to say shortly and with truth :— 1 See the gay cars in safety fly Majestically through the sky, Now near the earth, now high in air, Birdlike theyre coursing every where. New York. W. D. G. [[t is perfectly impossible for any man to move himself in the air by any known me-chanieal means, without being buoyed up by a gas much lighter than the atmosphere. One cubic foot of hydrogen, the lightest of all gases, willnot buoy up an ounce weight. The atmosphere is composed ot oxygen by weight 23 ; nitrogen, 77 ; their atomic weight, as related to hydrogen, are (23X8) -f- (77X14) — 100=12 62. There is also some carbonic acid gas in the atmosphere, but we may set it do wn at about 13 times lighter than hydrogen gas If one cubic foot of hydrogen cannot buoy up a one ounce weight, no man can force himself into the air by any machine, for if he could he would be able to jump over a mouatain. Some new power must oe discovered before we can fly—such a discovery may be near at hand; we would rejoice to behold it.