We give herewith an account of an aerial steam machine designed by Joseph M. Kaufmann, a Glasgow engineer, an account of which we. condense from Engineeriig of March 6, 1868. Only about two ninths of the wings, which are long and narrow, are represented in our engraving. From this remark the reader will understand they were of great length, and we may add that they were pointed somewhat like the wing of a swallow. The actual machine, which the model was constructed to represent, was designed to be of the following dimensions : From stem to stern, 12 feet ; from stem to tip of tail, 14 feet 11 inches ; greatest depth, 4 feet 6 inches ; greatest width, 5 feet 1 inch; length of each wing, 35 feet; area of each wing, 221 square feet ; length over the " gies," 17 feet 3 inches ; Length of pendule, 40 feet ; weight at end of pendule, 85 lbs.; total weight of machine, 7,000 lbs.; nominal power, 40-H. P.; intended speed, 40 miles per hour, the tank or tender taking a supply of oil and water sufficient for five hours. As will be inferred from the engraving, it is intended that progress should be gained by flapping the wings, these wings being driven in such a manner that their motion resembles that of the wings of a bird as closely as possible. It is intended that when the machine is rising, the wings should make 120 strokes per minute. The pendule, which can be raised and lowered as desired, is for the purpose of keeping the machine in a horizontal position. The machine represented is exclusively for flying over land, and it is furnished with wheels on which it can run when on the ground ; Mr. Kaufmann states, however, that by a few simple alterations it can be made available for traveling over water, and in case of its alighting be converted into a boat furnished with paddle wheels. The model, to which we have already referred, weighed, complete, 42 lbs.; and during the experiments with it, its boiler, owing to its small size, was not fired, steam being supplied from an independent boiler. The model was made entirely to prove the correctness of the inventor's theory, and to ascertain if the connections to the wings could be made strong enough to withstand the violent twisting and bending strains to which they are exposed. In the model the motive power consists cf a single vertical steam cylinder fitted with a piston in the usual way, the piston rod carrying a cross-head which is coupled by links directly to the wing beams. The wing beams are fitted to shafts which run for about three fourths the length of the machine. To these shafts are also connected the "regulators" by which the feathering motion of the wings is governed. Each wing is secured in four places, and has its center of oscillation directly opposite its working beam. The " gies " can be moved alternately so as to steer the machine either to the right or left without disturbing its horizontal position. I During the trial the model was securely fastened down and loaded with a considerable weight to prevent it from moving, it being at the same time raised on supports so that its wheels were clear of the ground. Steam at a pressure of 150 lbs. was then turned on, when the wings made a short series of furious flaps ; but, through imperfect workmanship, the left wing suddenly gave way about two feet from its base, when the other wing, being subjected to extra strain, failed also. Mr. Kaufmann states that these accidents were in a great measure caused by the wings having been lengthened three feet previous to the trial, and being thus exposed to a greater strain than they were constructed to resist. The wings having been removed the machine was put to thp filial test of be- ing run at a speed of 1,500 double strokes per minute, and it was found to be quite uninjured by this experiment. Altogether, Mr. Kaufmann considers the trials to have been satisfactory, and since the trial referred to he has been engaged in the construction of a larger machine on the same principle, but having the beams worked, through gearing and ecr centrics, by a horizontal engine. This machine is also to be fitted with shifting aero-planes, and is to be accompanied by a tank-car with accommodation for two persons. It is intended that this machine should rise into the air after a short race on terra flrma, drawing behind it the tank-carriage ; it is to be of 120-horse power, and is to weigh 8,000 lbs. complete. The tender is to carry ten hours' supply of fuel and three hours' supply of water ; and with this tender ind three cars the machine is intended to make fifty-six miles per hour.