A new and very ingenious method of space telegraphy is discussed at length in an article by Karl Zickler in the Elektrotechnische Zeitschrift. It depends on a phenomenon discovered by Hertz in 1887, viz., the influence of certain short wave-length light rays upon electrical discharges. The ultra-violet waves, which are obstructed by glass but transmitted by quartz, are the most effective. The source of light is an arc lamp. The light is passed through a lens of rock crystal to the receiver. The receiver is a glass vessel partially exhausted of air, one end of which consists of a truly parallel plate of rock crystal. In front of the receiver there is a condensing lens of rock crystal, and within the exhausted chamber are the two electrodes, one of which is an inclined disk and the other a small ball. The electrodes are connected with the secondary portion of an induction coil, and when the ultra-violet rays fall upon the inclined disk and are reflected to the ball, a discharge will be produced which may be read either with a telephone or a coherer. The signals are sent by alternately interposing a plate of glass in front of the rays issuing from the transmitter and removing it therefrom. Herr Zickler has made many experiments to verify his conclusions and appears to have demonstrated the feasibility of his idea in practice.
Mr. Dawson Williams has announced in Nature the discovery in many susceptible persons of a periodicity in the effects that follow a sting. The immediate result, he says, is a small flattened wheal, pale and surrounded by a zone of pink injection. This is attended by itching, but both wheal and itching are gone in less than an hour. About twenty-four hours later the part begins to itch again, and in a few minutes a hard, rounded, deep-red papule appears, and is quickly surrounded by an area of œdematous skin. The formication is intense, and in the affected area, while the ordinary sensations of touch are dulled, those of temperature and painful feelings are exaggerated. In two or three hours the itching diminishes and the œdema disappears, leaving a small, red papule, which itches but little. The phenomena recur, with diminished intensity, in the course of another twenty-four hours, and may return in this way, growing fainter all the time, in four or five daily repetitions. After these returns have ceased, a small, indolent papule may persist for weeks or months. This periodicity is not observed in all subjects, but most generally in those who suffer most.
Among the advantages of Linde's liquid-air process, Prof. J. A. Ewing, speaking at the English Society of Arts, claimed its giving a means of separating more or less completely the oxygen of the atmosphere from its associated nitrogen. After describing a process by which a liquid consisting largely of oxygen may be produced, the author said that the most interesting application of the liquid which had hitherto been tried on a commercial scale was to make an explosive by mixing it with carbon. When liquid air, enriched by the evaporation of a large part of the nitrogen, was mixed with powdered charcoal, it formed an explosive comparable in power to dynamite, and which, like dynamite, could be made to go off violently by using a detonator. The chief advantage of the explosive was its cheapness, the cost being only that of liquefying the air. Even the fact that after a short time the mixture ceased to be capable of exploding might be urged as a recommendation, for if a detonator hung fire, there was no danger of the charge going off accidentally some time after the explosion was due, nor was there any risk of its being purloined or used for criminal purposes.
NOTES.
According to the Tribune de Genève, twenty new hotels were opened in Switzerland in 1897, and twenty-five were enlarged, adding two thousand beds and making the whole number of beds about ninety thousand. The number of nights' lodgings furnished during the season is estimated at ten million. Supposing each guest to spend twelve francs a day, the total revenue from tourists would amount to one hundred and twenty million francs, or twenty four million dollars. Classifying the guests according to nationality, it is estimated that the Swiss constitute eighteen per cent of the whole, Germans thirty-four per cent, English sixteen per cent, French twelve per cent, Americans eight per cent, and those of other nations twelve per cent.
A list of women astronomers, compiled by Herman S. Davis from Ribiere's Les Femmes dans la Science, contains as contemporary workers in the science the names of seventeen American women who have taken part in astronomical computations or are teachers of astronomy, and twelve who are working in the application of photography to astronomy. Of the women in the later list, Miss Ida C. Martin, Miss Dr. Dorothea Klumpke (now in the Paris Observatory), and Mrs. M. P. Fleming have attained distinction for successful original researches.
The object of the Pure Food and Drug Congress, which met in Washington in March, 1898, with Joseph E. Blackburn, of Columbus, Ohio, as president, is declared in its resolutions to be to secure suitable national legislation to prevent the adulteration of food, drink, and drugs, to secure the enforcement of laws, and secure and promote uniformity of State legislation looking to that end; to create and maintain a high public sentiment on these subjects, to sustain public officers enforcing the laws respecting them; and to promote a more general intelligence concerning the injury to health and business interests resulting from food adulteration. In this work all are invited to join. The congress was in session four days, and several important papers were read to it.
The large Atlantic coastal plain beginning with southern New Jersey, Mr. John Gifford affirms, in The Forester, would soon be capable, if protected from reckless devastation, of producing almost limitless quantities of the valuable smooth-bark or short leaf pine. In Northampton and Accomac Counties, Virginia, lying in this plain, the forests are already properly cared for and propagated without the aid of forest laws. This is done by insuring their freedom from fire, which is attended to purely as a matter of present economy. The value of the woods in holding the loose sandy soil and as windbreaks is recognized, and the litter of the pine trees is a precious dressing for the sweet potato fields. This litter, of pine "chats," "needles," or "browse," is carefully raked off every year and spread on the fields, and there is nothing left in which fire can start.
The Lalande prize of the French Academy of Sciences has been conferred upon Prof. S. C. Chandler, of Cambridge, Mass., in recognition of "the splendor, the importance, and the variety" of his astronomical work; the Damoiseau prize upon Dr. George William Hill, of Washington, for his researches in mathematics and astronomy; and the Henry Wilde prize on Dr. Charles A. Schott, of Washington, for his researches in terrestrial magnetism.
Prof. J. Mark Baldwin, of Princeton, author of the books The Development of the Child and the Race, Handbook of Psychology, and The Story of the Mind, has been elected a member of the French Institute of Sociology.