* * * * * Prof. A. E. Dolbear, of Tufts College, Massachusetts, patented an invention for telegraphing without wires in 1886, which he claims covers all that Marconi is doing. He has sent messages with it for as long distances as five miles. According to his account he invented the system and made successful experiments with it as far back as 1882. He made an application for a patent, which was rejected by the Patent Office with the statement that it was contrary to science and would not work. “But as it did work, the claim was maintained in the office, and four years later, in 1886, a patent for it was issued.” Professor Dolbear does not wish it to be understood that his patent is on the “art of wireless telegraphy,” but that it covers everything that has been so far done in the art. * * * * * On the occasion of the visit of the French Association to the British Association, Prof. J. J. Thomson gave an exposition of the lines of research by which it has been concluded that the atom is not the smallest existing quantity of matter. Electro-chemical phenomena teach us to associate a definite amount of electricity with each atom of matter; but these recent researches indicate that under certain circumstances a much larger quantity of negative electricity may be conveyed by the atom, or else that the negative electrical charge resides on a small detachable portion of the “atom,” which alone is concerned in the experiments. The positive charge seems to be distributed over the whole mass of the atom. * * * * * The merits of two methods of clarifying sewage--by dilution and by bacterial action--are discussed by Mr. Rudolph Hering in articles in the Engineering Magazine. Disposal by dilution in large streams of water is regarded as satisfactory in many places--where the water of the stream is not to be used for drinking or cooking--provided the flow of the stream is always copious enough to dilute and disperse the sewage so widely as to prevent putrefaction and substitute oxidation. For purification by bacterial action no single method is found adapted to all conditions. The method by filtration and aëration is declared practicable only in localities where a sufficient area of porous land is available, upon which the crude sewage can be spread in sufficient quantity, into which it can filter with the proper velocity, and from which it can emerge as a thoroughly purified water. Where these conditions are absent, other methods must be adopted, of which the experiments in artificial filtration by tanks, as practiced at Exeter and Sutton, England, are described. These experiments promise to improve the present method, but perhaps not as greatly as is anticipated by the promoters. The author regards a prior separation of the suspended or dissolved organic matter as essential to permanent success when the amount of land is limited.