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  or diluted acid, but the cause of the property has not hitherto been satisfactorily explained. M. Louis Varenne reported recently to the French Academy of Sciences that he had remarked that passivity was destroyed and the metal could be made to yield to the solvent action after a shock or jar was given to it, or a current of carbonic acid or hydrogen gas was passed over it. He was led to believe that an envelope of gas was formed around the metal which protected it, and, on examining some passive iron, found that it was actually covered with a layer of gas. The metal was then placed in a receiver and a vacuum was produced, with care not to touch the iron or disturb it in any way, after which it was plunged into the diluted acid, when it was readily attacked. The nature of the protecting gas was ascertained by introducing a little air into the exhausted receiver, when the orange color characteristic of the nitrous vapors was observed. The gaseous sheath is, therefore, chiefly composed of the deutoxide of nitrogen.

 

Berlin Geographical Society recently celebrated the birthday anniversary of Carl Ritter, the famous German geographer. He founded the society in 1828, and presided over it until 1860. The university, the army, and various German societies, were largely represented, and handsome subscriptions were announced for a memorial to the hero of the evening.

death is announced, on the 19th of December last, of Francis Boll, Professor of Comparative Physiology in the University of Rome. Though young, Professor Boll had contributed effectively to the advance of medical science by his physiological researches.

has been a mooted question among physiologists whether saliva is destroyed in the gastric juice, or whether it continues its activity upon starch in the stomach. Recent researches by M. Defresne seem to prove that saliva is rendered entirely inactive in pure gastric juice; but that in gastric juice combined only with organic acids the conversion of starch into sugar proceeds as in the mouth.

is announced that Leibnitz's calculating machine has been found. During his stay in Paris, in 1672, Leibnitz invented and constructed this machine, which was the wonder of the time. It can add, subtract, multiply, and divide. It early became the property, of the Hanover Public Library, but long since disappeared from its treasures. Nothing was known of its whereabouts, except that it had been sent to an instrument-maker at Göttingen to be repaired. Through the efforts of Dr. Bodemann it has again come into the possession of the Public Library at Hanover.

"Pall Mall Gazette" is authority for the statement that California whalers returning to San Francisco report the death by starvation of large numbers of Esquimaux in the vicinity of Behring's Strait. This is ascribed to the scarcity of walrus-meat, caused by the indiscriminate destruction of these animals by American whalemen—as many as a hundred thousand a year, it is said, having been killed by them.

in a paper on the preservation of timber, read lately before the Engineers' Club of Philadelphia, stated that creosoted ties in use for twenty and twenty-two years in England were still in as good a state of preservation as when first laid down. Creosoted piles driven at Portsmouth, England, forty-two years ago, were now as good above as below the water-line, and have out-lasted sixteen sets cut from the same timber, and driven in the same work, but which were not creosoted.

writes to "Nature" that our knowledge of the mineral waters of Hungary is altogether fragmentary and imperfect in kind. In the interest of truth he points out that a work, bearing the title "Les Eaux Minérales de la Hongrie," published under the auspices of the Hungarian Commission of the last Paris Exhibition, is altogether unreliable, and, in support of this opinion, states that the book enumerates less than forty per cent, of the localities in Hungary at which mineral springs occur; and, of the analyses published in the book, only those made twenty or thirty years ago find a place, the more recent and valuable ones being entirely omitted.

F.R.S., whose botanical researches in South America, begun over fifty years ago, gave him a distinguished place among the botanists of England, died in London, October 17, 1879, aged ninety-one years. In 1825 he published "Travels in Chili and La Plata," and in later years contributed many interesting and valuable botanical papers to the "Transactions of the Linnæan Society." He bequeathed his herbarium of South American plants, numbering over 20,000 sheets, original drawings and manuscripts of his published works, and also some unpublished manuscripts, to the British Museum. 