NOTES. 



H3 



trical apparatus, where it would have to 

 withstand a white heat. Mr. Dudley under- 

 took the removal of the phosphorus, and 

 found that this could be effected perfectly 

 by heating the metal with lime in an elec- 

 tric furnace. The manufactured metal will 

 then resist as much heat without fusion as 

 the native metal. Iridium is sawed by a 

 copper disk between four inches and eight 

 inches in diameter, making twenty-five hun- 

 dred revolutions a minute, and dipping into 

 a bath of cotton-seed oil and corundum or 

 diamond-dust. Many new uses are open- 

 ing for it since it has been possible to 

 melt and cast it. It is used for draw-plates, 

 to replace the ruby plate, in the manufacture 

 of gold and silver wire; for knife-edges 

 for scales and balances ; for tipping hypo- 

 dermic needles; for the negative poles of 

 arc-lamps; and for many other purposes. 

 One of the most important applications is 

 for the contact-points of telegraphic instru- 

 ments. These points outlive many platinum 

 contacts, and do not oxidize or stick. Mr. 

 Dudley is making experiments, with a fair 

 promise of reaching commercial success, in 

 the electric deposition of iridium. 



The Chaldean Lunar Cycle. M. Oppert 

 recently read a paper before the Academy 

 of Inscriptions and Belles-Lettres on an As- 

 syrian inscription concerning lunar cycles. 

 More than twenty years ago he discovered 

 in the inscriptions of King Sargon allusions 

 to a great lunar cycle one of the revolutions 

 of which terminated in the year b. c. 712. 

 He was afterward convinced that this cycle 

 was the period of 1805 years, after which 

 the series of lunar eclipses recur in the same 

 order. The knowledge of this period sup- 

 poses continuous astronomical observations 

 among the Chaldeans already of many cent- 

 uries' duration. They began the calcula- 

 tion of the period from the year 11,542 be- 

 fore our era. This is also the year in which 

 the Sothiac periods (of the Egyptians) of 

 1460 years begin, one of which ended b. c. 

 139. These two cycles of 1460 years and 

 1805 years play an important part in the 

 chronological computations of the ancient 

 East. Twelve of each of them form re- 

 spectively 17,520 and 21,660 years, or 292 

 and 561 sixties of years, numbers which oc- 

 cur in the Bible, according, to M. Oppert, to 



express the length of time between the Flood 

 and the birth of Abraham, and from the 

 birth of Abraham to the end of the history 

 in Genesis. 



NOTES. 



Thirty years ago pines were planted in 

 the Sologne, a tract of waste land near Blois, 

 France. Fifteen years afterward, as the 

 pines were cut away, oaks sprang up spon- 

 taneously to take their places, thus tending 

 to restore what history tells was the ancient 

 vegetation of the country. M. Emile Hau- 

 sen-Blangstcd states, in illustration of the 

 struggle for existence among trees, that the 

 pine is dislodging the larch in the Grisons, 

 while there and in the Jura the beech pre- 

 vails over both. In Switzerland generally 

 the beech gains the place of the oak, fir, and 

 birch, and in Prussia the pine encroaches 

 on the oak and the birch. Birches and the 

 ash are extending themselves in the pine- 

 forests of Russia, and the birch is dislodg- 

 ing the aboriginal pines in Siberia. 



Mr. Frederick Ransome is making a 

 cement from blast-furnace slag and lime, 

 much superior to the cements previously 

 made from this refuse matter. He uses 

 lime from the gas-works, gets rid of the 

 sulphur by calcination with coal or coke, 

 and then dissipates it in the form of sul- 

 phureted hydrogen. While Portland ce- 

 ment breaks under a load of 818 pounds, 

 this cement, under the same circumstances, 

 exhibits a power of cohesion up to 1,170 

 pounds. 



The Convallaria pob/gonatum, whose 

 name indicates its relation to the lilies- 

 of-the-valley, may fairly be described as a 

 traveling plant. It has a root formed of 

 knots, by which it annually advances about 

 an inch from the place where the plant was 

 first rooted. Every year another knot is 

 added, and this drags the plant farther on ; 

 so that in twenty years' time the plant will 

 have traveled about twenty inches from its 

 original place. 



The continued publication of the " Index 

 Medicus" has been undertaken, after ar- 

 rangement with the editors and the rep- 

 resentatives of the late Mr. F. Leypoldt, 

 the former publisher, by Mr. George S. 

 Davis, of Detroit. The first number of the 

 journal for the current year, having been 

 necessarily delayed, will comprise the lit- 

 erature of January, February, and March. 

 Further publication will be made monthly as 

 usual. At the end of the year, in addition 

 to the usual index of names, subscribers 

 will be furnished with an index of subjects 

 to the volume. 



