200 



SCIENCE. 



[Vol. I., No. 7. 



barium peroxide, lieat is evolved: Ba02 + 2HC1 = 

 BaCl, + HiOj, + 11 cal. — (Comptes rendus, xcvi. 

 88.) c. F. M. [425 



Electric conductivity of silver chloride, bro- 

 mide, and iodide. — W. Kolilrausch finds that silver 

 salts of the halogens offer less resistance to an electric 

 current than sulphuric acid. In the order of their 

 conducting-power, the chloride stands first, the iodide 

 last, and the bromide occupies an intermediary posi- 

 tion. — (^'Inii. c/ii'ii. p/)?/s., xxvii. 612.) c. P. M. [426 



Antiseptic character of carbonic-dioxide gas. 



— In an atmosphere of this gas, H. Kolbe finds that 

 the quality of fresh beef can be preserved for several 

 weeks, even in a warm room. Fish, game, mutton, 

 and veal begin to decay after a few days. — (Journ. 

 Pralct. chem., n.f. xlvi. 249.) c. F. M. [427 



Investigations on uranium. — For the atomic 

 weight of uranium, the values 120, ISO, and 2-40 have 

 been proposed, the latter appearing in Mendelejeff's 

 classification. In order to decide which of these 

 values is correct, C. Zimmermann determined the 

 vapor density of the tetrabromide and tetrachloride, 

 and the specific gravity and specific heat of the metal. 

 Vapor density of the tetrabromide obtained, 19.46; 

 calculated for UBrj (U = 240), 19.36: of the tetra- 

 chloride obtained, Vi.S ; calculated for UCI4 (U = 240), 

 13.21. The metal was prepared by ignition of a mix- 

 ture of the chloride with sodium covered with salt. 

 Specific gravity, 18.7; atomic volume. 12.84; specific 

 heat of the melted metal, 0.0276.5. This value mul- 

 tiplied by the atomic weight (240) gives, as the atomic 

 heat, 6.64; the law of Dulong and Petit requiring 

 6.64. Uranium must therefore occupy a position in 

 the sixth group of the periodic system with chromium, 

 molybdenum, and tungsten. — {Ann. der chem., 216, 

 1.) c. F. M. [428 



Heat of formation of volatile organic bodies. 



— The heat of formation of such compounds as car- 

 bon tetrachloride, chloroform, and perchlorethylen 

 has not been determined, on account of the great 

 difficulty of obtaining complete combustion. In the 

 combustion of compounds of chlorine and carbon 

 containing a small percentage of hydrogen, Julius 

 Thomsen obtains accurate results by burning the 

 volatile substance, mi.Ked with hydrogen, in a special 

 form of apparatus, which he has devised for this pur- 

 pose. Thomsen concludes from his results, that car- 

 bon possesses an equally strong affinity for hydrogen 

 and chlorine. The heat of formation of ethylen and 

 perchlorethylen are nearly the same; and, assuming 

 14,l;W cal. as the most probable value of the double 

 bond between the carbon atoms, the affinity of a 

 hydrogen atom for carbon would be 15,080 cal., and 

 that of a chlorine atom, 14,:i30 cal. — (Berickte deutscli. 

 chem. yesellsch.jXV. 2'Mi.) c. F. M. [429 



Constitution of carbonic acid. — Since a solu- 

 tion of carbonic dioxide in water di.^solves magnesium 

 with evolution of hydrogen, M. Ballo concludes that 

 it contains the liydrated aciil HXO:,. As a further 

 proof, he mentions the fact that potassium aiul sodi- 

 um bicarbonates dissolve magnesium, forming the 

 carbonate MgCO.v 311.^0. Tlie formation of mag- 

 nesium sulphite, by the action of SO.2 in solution 

 upon the metal, indicates the hydrated acid H2SO3. 



— (Berichf.e deulsch. chem. gesellsch., xv. 300:!.) 

 C. F. M. [430 



MINERALOGY. 

 Jade. — Two specimens, — one from the Karakash 

 valley, southern Turklstan, from a mine formerly 

 worked by the Chinese ; the other from Nevv Zealand, 



— upon analysis, gave G. L. Allen results agreeing with 

 amphibole. — {Chem. news, xlvi. 216.) s. l. p. [431 



Cryolite. — A review of the history of the fluorine 

 minerals, especially those occurring with cryolite from 

 Greenland, is given by P. Groth along with results of 

 renewed crystal lographic and chemical investigation. 

 Crystals of cryolite, after having been identified and 

 measured, were given over for chemical analysis to J. 

 Brandl, whose results agreed very closely with the 

 composition expressed by the formula 3 NaF, Al F3. 

 The results of the renewed crystallographic measure- 

 ments prove the mineral to be monoclinic with the 

 axial relation a:b: c = 0.9662 : 1 : 1.3882. /3 = 89° 

 49'. The optical deportment of the mineral also indi- 

 cates its monoclinic character. — {Zeitschr. kryxt., 

 vii. 375. ) s. I,, p. [432 



HomeSite. — Accompanying nagyagite from Nag- 

 yag, M. E. Bertrand has identified crystals of a pale 

 rose color, very soft, and easily cleavable in one direc- 

 tion, which, upon chemical examination, proved to be 

 a hydrated arseniate of magnesia containing a little 

 calcium and manganese. The mineral is supposed to 

 be identical with the hornesite described by Haidin- 

 ger. — {Bull. soc. min., v. 306.) s. L. P. [433 



PHYSICAL GEOGRAPHY. 



Former great tides. — Prof. R. S. Ball, in a 

 second lecture on this question, reviews the criti- 

 cisms of his previous statements, and repeats his 

 belief that the accumulation of the oldest stratified 

 rocks was very probably aided by this newly dis- 

 covered and very important agent; namely, the 

 stronger tides produced by the moon when not so far 

 from "the earth as it now is. — (Nature, Dec. 28, 1882. ) 

 w. M. D. [434 



Gulf-Stream. — Commander Bartlett's recent 

 measures on the coast-survey steamer Blake show 

 that the current off Florida, where the channel is 48 

 miles wide, and the deepest point 439 fathoms, has a 

 cross-section of 429,526,240 a feet; a velocity from one 

 to five, averaging three miles an hour; a discharge of 

 51,000,000,000,000 gallons an hour; and a temperature 

 varying fi-om 78° to 83° at the surface, and from 57° 

 to 44° at the bottom. Farther along our coa<t, the 

 current flows over an even plateau, narrowing toward 

 Cape Hatteras, about 400 fathoms deep, and suddenly 

 dropping off to over 2,000 fathoms at its eastern edge. 

 In the stronger parts of the stream, the bottom is swept 

 clean, and consists of firm coral rock, hard enough to 

 dent the brass cylinder of the sounding-apparatus. 

 Where fine deposits occur, south of Charleston, they 

 are of pteropod ooze, characteristic of the Caribbean 

 and Gulf of Mexico; farther north, globigerina ooze 

 becomes more common, as it is in the open north At- 

 lantic. The division between these two deposits is 

 considered the boundary of the cold, aictic current 

 which follows down our shore from the north, passing 

 under the Gulf-Stream off Hatteras, where the shal- 

 low plateau forces it out. No warm and cold bands or 

 bifurcations were fouiul in the surface-waters till off 

 Hatteras, and no distinct ' cold wall.' Near shore the 

 current was much influenced by winds. A brief de- 

 scription is given of the Siemens deep-sea thermome- 

 ter, based on the variation of electrical resistance in 

 metals with change of temperature. Measures made 

 with this and with the Miller-Casella thermometer 

 show almost absolute agreement, even at consiilerable 

 depths. — {Bull. Amer. (jeotir. soc, 1882, 69. Further 

 account of Bartlett's work may be found in Proc. 

 U.S. naval inst., vii. 1881, 25; viii. 1882, 221.) 

 w. M. D. [435 



GEOGRAPHY. 

 (J^iirope.) 



French census of 1881. — After deducting the 

 number of foreigners temporarily resident in France, 



