720 



THE POPULAR SCIENCE MONTHLY. 



mon or diluted acid, but the cause of the 

 property has not hitherto been satisfactorily 

 explained. M. Louis Varenne reported re- 

 cently 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 pro- 

 tected 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 at- 

 tacked. 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, there- 

 fore, chiefly composed of the deutoxide of 

 nitrogen. 



NOTES. 



The Berlin Geographical Society recent- 

 ly celebrated the birthday anniversary of 

 Carl Ritter, the famous German geographer. 

 He founded the society in 1828, and pre- 

 sided over it until 1860. The university, 

 the army, and various German societies, 

 were largely represented, and handsome 

 subscriptions were announced for a memo- 

 rial to the hero of the evening. 



The death is announced, on the 19th of 

 December last, of Francis Boll, Professor 

 of Comparative Physiology in the Univer- 

 sity of Rome. Though young. Professor 

 Boll had contributed effectively to the ad- 

 vance of medical science by his physiologi- 

 cal researches. 



It 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. Re- 

 cent researches by M. Defresne seem to 

 prove that saliva is rendered entirely inac- 

 tive in pure gastric juice ; but that in gas- 

 tric juice combined only with organic acids 

 the conversion of starch into sugar proceeds 

 as in the mouth. 



It is announced that Leibnitz's calculat- 

 ing 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, sub- 

 tract, multiply, and divide. It early be- 

 came 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 Gottingen to be 

 repaired. Through the efforts of Dr. Bode- 

 mann it has again come into the possession 

 of the Public Library at Hanover. 



The " Pall Mall Gazette " is authority for 

 the statement that California whalers return- 

 ing to San Francisco report the death by star- 

 vation 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 hun- 

 dred thousand a year, it is said, having been 

 killed by them. 



Mr. Billin, in a paper on the preserva- 

 tion of timber, read lately before the En- 

 gineers' 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, Eng- 

 land, 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 w ere 

 not creosoted. 



M. J. Bernath writes to " Nature " that 

 our knowledge of the mineral waters of Hun- 

 gary is altogether fragmentary and imper- 

 fect in kind. In the" interest of truth he 

 points out that a work, bearing the title 

 "Les Eaux Minerales de la Hongrie," pub- 

 lished under the auspices of the Hungarian 

 i Commission of the last Paris Exhibition, is 

 altogether unrehable, and, in support of this 

 opinion, states that the book enumerates less 

 than forty per cent, of the localities in Hun- 

 gary 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 be- 

 ing entirely omitted. 



John Meaks, F. R. S., whose botanical re- 

 searches in South America, begun over fif- 

 ty 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 con- 

 tributed many interesting and valuable bo- 

 tanical papers to the '' Transactions of the 

 Linna;an Society." He bequeathed his her- 

 barium of South American plants, number- 

 ing over 20,000 sheets, original drawings 

 and manuscripts of his published works, and 

 also some unpublished manuscripts, to the 

 British Museum. 



