During recent years, a considerable amour of work has been done in attempting to solv the problem of artificial flight, and in the mai this work has been very successful. One by on the difficulties which beset the problem have been overcome, and now apparently there : only one difficulty which stands between us an the solution of the problem—namely, the diffculty of balancing the machine. In the follow ing paper an attempt is made to further tb solution of this difficulty, by showing that it : capable of mathematical treatment.

We have not attempted to deal exhaustivel with the question ; we have confined ourselve to the consideration of simple forms of glider and the chief object of the paper is to draw the attention of all interested in the problem artificial flight to the capabilities of this method.

A memoir of the late Mr. James Glaisher, F.R.S., appeared in the April number of the Aeronautical Journal, so it seems hardly necessary for any further reference to be made to him. But since that time the instruments and apparatus used by him in his famous balloon ascents have, by the courtesy of his son, Dr. J. W. L. Glaisher, F.R.S., come into the possession of the Royal Meteorological Society.

Your Secretary, Mr. E. S. Bruce, was very desirous that these instruments should be exhibited at a meeting of the Aeronautical Society, and thought that it would be interesting to most of the members if a brief account of Mr. Glaisher's balloon ascents was given at the same time. I could not refuse this request, as Mr. Glaisher was for some time my chief at the Royal Observatory, Greenwich, although I think a more interesting account might have been prepared by someone else.

In commencing the paper which I am about to read I would like, first of all, to make a few remarks as to what has been done towards solving the difficult, yet extremely fascinating problem of aerial flight.

In recent years much has been attempted, but, when all is weighed in the balance, I venture to think that comparatively nothing of any value has yet been accomplished, and the successful flying machine has yet to come. A debt of gratitude is due to M. Santos Dumont. M. Lebaudy, and other pioneers, for breaking down, as they have, prejudice against the subject; but, after all, do his or their machines embody any new principle ? Only by careful attention to certain mechanical details and a combination of mechanism already in existence have they accomplished what they have.

It is unnecessary for me to go into details of the defects of navigable air-ships. Most students of aeronautics are, I think, agreed that the flying machine of the future will be one which is heavier than the atmosphere and presents the least surface of resistance when travelling horizontally.