I suggest that the propelling wheels be placed in some other position than that given in the said description. From what little knowledge I possess of aerial navigation, I am persuaded that it would take less power to propel the "Aeroport" at a given speed, if the wheels were placed at the rear or front portion of the flying ship. My reason for being thus persuaded is, that as the forward and aft halves of the float are cone-shaped--the center being the base, and the front and rear ends being the vertexes--there must be an increased velocity of the atmosphere from front to aft as the aeroport advances. Consequently the driving wheels being placed under the center or largest diameter of the float, they must evidently revolve with greater rapidity in the current of air passing between the float and the saloon, going in opposite direction to that in which the aeroport is flying at a given speed, than they would were they placed in front or behind where the atmosphere is comparatively at rest. I take this view from the fact that steamboats and other vessels proceed with greater speed, with a given power, _down_ stream than they do _up_ stream, mostly on account of the paddles striking against the current flowing in the same direction in which the vessel is rowing. The propelling wheels placed either at the front or rear may have the axle extended through the end of the float to the center, and the cog-wheel, for the chain, placed on the inner end of the axle, and the chain descending through the bottom of the float, and connected to the engine in the same manner as given in your paper. The chain should be inclosed from the float to the saloon below, with a pipe of the same material as the float, and sufficiently large to insure the free action of the chain, and the axle of the propellers should be made tight with suitable packing to prevent the escape of gas. However there may be different arrangements employed for connecting the engine to the wheels. A shaft extending directly under the float, and reaching from the center to the axle supporting the propellers, and connected therewith by means of side cog-wheels, might be used; and as the shaft would necessarily diverge from a straight line with the said axle, the shaft having the chain-wheel on the end directly over the engine and connected therewith in the manner proposed by Mr. Porter, I would suggest further that it would, perhaps, be preferable to place the wheels at the front end, that the rudder might remain in its original position, and the aeroport could swing behind the propellers on encountering side currents of air, and could thus be more easily guided. I firmly believe that Mr. Porter has taken "the right step in the right direction" to accomplish that which has been so long sought, and which evidently will be accomplished at some future time. The air will yet be navigated by numerous flying ships, going from one city to another like those that now cover the broad bosom of our oceans.