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Congress the army board was unwilling to continue the work. In the meanwhile the Wright brothers had begun their experiments with flying machines and in the year of the trial of the Langley aerodrome accomplished their first flight with a motor. In 1905 they remained in the air for half an hour, but it was not until 1908 that they fully demonstrated the practicability of sustained flight. Langley died on February 27, 1906, at the beginning of the era of mechanical flight to which his researches had so largely contributed.

presided over the recent meeting of the British Association for the Advancement of Science at Portsmouth, and, like many of his predecessors in the chair, made an address that is of very general interest. He gave a clear account of ancient and modern views regarding the chemical elements, laying, as is natural, much stress on the new discoveries in which he himself has taken such a leading part. It is not possible to review the marvelous story of the recent developments of chemistry more concisely than is done in the address. It is of interest to note that fair William Ramsay maintains, though rather incidentally, the validity of his experiments from which he concluded that the metal copper is converted partially into lithium by the energy radiated from radium, and that thorium, zirconium, titanium and silicon are degraded into carbon. It will be remembered that Madame Curie was unable to confirm these results.

Sir William Ramsay passes from the disintegration of the atom to the question of the available supply of energy, especially for Great Britain. He tells us that each Greek freeman had five helots who did his bidding, saving him from manual labor and giving Athens its preeminence in literature and thought, but that people in Great Britain are still better off, each family having twenty helots represented by the consumption of fifty million tons of coal annually. It is this coal which has given England its great wealth and commercial supremacy. At the present rate of increase of consumption the supply will be exhausted within 175 years, and there appears to be nothing