Meanwhile, whatever may be the future achievements of this new _supermarine_ wireless telegraphy conducted over long distances, there can be no question as to its enormous utility and present value for intercommunication between ships on the ocean and ships and the shore. At the present time, there are some forty or more of the transatlantic ocean liners and many other ships equipped with this Hertzian wave wireless telegraph apparatus on the Marconi system. Provided with this latest weapon of applied science, they are able to chat with one another, though a hundred miles apart on the ocean, with the ease of guests round a dinner table, to exchange news or make demands for assistance. Ships that pass in the night, and speak each other in passing-- Only a signal shown, and a distant voice in the darkness; So, on the ocean of life, we pass and speak one another, Only a look and a voice, then darkness again, and a silence. Abundant experience has been gathered to show the inexpressible value of this means of communication in case of accident, and it can hardly be doubted that before long the possession of this apparatus on board every passenger vessel will be demanded by the public, even if not made compulsory. Although the privacy of an ocean voyage may have been somewhat diminished by this utilisation of ether waves, there is a vast compensation in the security that is thereby gained to human life and property by this latest application of the great energies of nature for the use and benefit of mankind. GEO. TUEKER, PRINTER, SALISBURY COURT, FLEET STREET, LONDON. [1] This series of articles is based on the Cantor Lectures delivered before the Society of Arts, London, in March, 1903. The lectures were attended by many of the leading British scientific men and electrical engineers, and attracted wide attention as the most complete and authoritative statement hitherto made of wireless telegraphy. In writing the articles for the "Popular Science Monthly," the author has omitted advanced technicalities in order that the substance may be suitable for the general reader.--EDITOR. [2] For a more detailed account of this hypothesis, the reader is referred to an article by the present writer, entitled "The Electronic Theory of Electricity," published in the "Popular Science Monthly" for May, 1902. [3] See J. J. Thomson, "Recent Researches in Electricity and Magnetism," chap. I., p. 16. [4] See O. Heaviside, "Electromagnetic Theory," Vol. I., p. 54. [5] Wiedemann's _Annalen_, 36, p. 1, 1889; or in his republished Papers, "Electric Waves," p. 137, English translation by D. E. Jones. [6] The fraction 7/22 here denotes a stranded wire formed of seven strands, each single wire having a diameter expressed by the number 22 on the British standard wire gauge. [7] G. Marconi, "Syntonic Wireless Telegraphy," _Journal_ of the Society of Arts, Vol. XLIX., p. 501, 1901.