576 



SCIENCE. 



I Vol. ir., No. Zd- 



resisted the severe tests of winter. Colors may be 

 introduced satisfactorily. — {Les mondes ; Amer. 

 arch., Sept. 1.) c. e. g. [311 



CHEMISTRY. 

 (^General, physical, and inorgmnc.) 



The yelloTV and red plumbic oxides. — A study 

 of the formation and properties of the two forms 

 of plumbic oxide, by A. Geuther, shows that it is di- 

 morphous, the yellow modification crystallizing in 

 rhombic forms, and the red in the tetragonal system. 

 The yellow oxide is changed by pressure and by fric- 

 tion into the red form, which is again transformed 

 into the yellow, when heated to its melting point. — 

 (Ann. cliem., ccxix., 56.) c. p. m. [312 



Artificial reproduction of barite, celestite, and 

 anhydrite. — A. Gorgeu finds that the sulphates of 

 barium, strontium, and calcium dissolve freely in the 

 melted chlorides of various metals at a red heat. On 

 cooling, they separate in well-defined crystals which 

 resemble closely the natural sulphates. From the 

 results of his experiments, M. Gorgeu concludes that 

 the minerals barite, celestite, and anhydrite must 

 have been deposited from a solution of their amor- 

 phous sulphates in some metallic chloride. — ( Comptes 

 rendus, xvi. 1734. ) c. F. M. [313 



A modification of V. Meyer's apparatus for 

 vapor density determinations. — In order to ob- 

 tain a uniform temperature, H. Schwarz surrounds 

 the tube containing the substance with a jacket which 

 serves as an air-bath. The required temperature 

 is obtained by placing the apparatus in an ordinary 

 combustion-furnace. — (Berichte deutsch. chem. r/e- 

 sellsch., xvi. 1051.) c. f. m. [314 



METEOROLOGY. 



Barometric laws. — The weather review issued 

 by the Deutsche seewarte contains not only summa- 

 ries of the weather canditions in each month, and of 

 the work of the bureau in connection with them, but 

 also occasional articles of scientific value, based irpon 

 the observations. The number for the year 1SS2 con- 

 tains a valuable paper entitled Typixche xoitteriings- 

 erscheinungen, the object of which is to discuss the 

 laws governing the velocity and direction of the 

 movement of areas of low pressure, and their attend- 

 ant phenomena, deduced from European observa- 

 tions between 1876 and ISSO. The low areas during 

 this period are groujied into five classes, according to 

 the directions of the paths which they pursued. The 

 accompanying charts exhibit, for each of three posi- 

 tions of the storm-centre (the entrance, middle posi- 

 tion, and departure, as regards the territory of western 

 Europe), six attendant phenomena, — the distribution 

 of pressure and temperature, barometric changes in 

 the preceding twenty-four hours, temperature depar- 

 tures from the normal, amount of precipitation, and 

 cloud-phenomena. Tables are also given showing the 

 distribution of the storm-tracks, with respect to the 

 time of year, the average depth of the depressions, and 

 their velocity. 



The discussion to which the charts and tables have 



been .subjected bring* out various empirical laws, 

 which are of special aid to the officers of the seewarle 

 in their weather forecasts, as well .as of scientific in- 

 terest. Several of these may be mentioned : 1°. The 

 depressions usually advance in the direction of the 

 strongest winds. 2°. The line of advance of the de- 

 pression forms an angle with the line of greatest in- 

 crease of temperature, which generally lies between 

 45° and 90°, the highest temperature lying at the 

 right of the path of the minimum. In summer the 

 angle is greater than in winter, often reaching 90°. 

 Both of these laws conform to the principles laid 

 down in 1S72 by Ley. They may be combined into 

 one as follows: "The onward movement of the de- 

 pressions follows approximately in the direction of 

 the preponderating movement of the whole mass of 

 air in the vicinity of the depression." The impor- 

 tance of cloud-studies, especially of the upper clouds, 

 consists in the fact that their direction of movement ■ 

 foreshadows, in a general way, the direction of move- 

 ment of the depression. On the other hand, their 

 distribution in advance of the depression is so irregu- 

 lar that their indications cannot be relied upon alone, 

 but must be combined with the distribution of press- 

 ure and other meteorologiGal conditions. 



The most interesting part of the discussion relates 

 to the distribution of presstire at the height of 2,500 

 metres. The barometric readings are reduced to this 

 height (in addition to the usual reduction to sea- 

 level) by means of Koppen's formula, published in 

 1SS2 ; the first use of this method which has yet been 

 published, as far as known. At this height the mini- 

 ma are not so closely enclosed by the isobars as is 

 indicated by the charts; and it is shown, that "the 

 rotary motion is limited to the lower atmospheric 

 strata, in which the axis of the vortex is inclined 

 towards the left and apparently somewhat forward."' 

 It seems that an advance in our knowledge of baro- 

 metric movements might be made by further atten- 

 tion to this method of research, which enables us to 

 investigate the extent of a depression in a vertical 

 direction as well as in the horizontal direction, to 

 which investigation has hitherto been limited. — 

 (Monatl. iibersichtwitteruwj,lS%i.) w. u. [315 



GEOGRAPHY. 



{Arciic.) 

 Polar stations. — The Austrian ste.amer Pola 

 reached Jan Mayen, Aug. 3, and found the party 

 in excellent health and spirits. We have already an- 

 nounced their safe return to Vienna. Some account 

 of the wintering is given in Nature, from which we 

 learn, that, in 1882, the autumn storms began with a 

 heavy snowfall about the end of August. Septem- 

 ber was fine and warm ; October again stormy. The 

 polar night began Nov. 12, and ended Jan. 30. Au- 

 rora was constant and of great brilliancy during the 

 winter. The greatest cold (—63° l'\) was observed 

 in January, but March had the lowest average tem- 

 perature. Terrible snow-storms occurred at inter- 

 vals; the ice, which first formed around the island in 

 December, being frequently broken up, and the salt 

 spray carried a long distance inland. The ice dis- 



