July 28, 1892] 



NA TURE 



hanging wall of black carbonaceous shale and a foot wall of grey 

 inagnesian limestone, which is probably of lower carboniferous 

 a^re'! The ore is richest and most abundant immediately under 

 the black shales. Other minerals observed are native silver, 

 argentite, galena, sphalerite, siderite, barite, and calcite. — Post- 

 Laramie deposits of Colorado, by Whitman Cross. This paper, 

 published by permission of the director of the United States 

 ( leological Survey, deals with some beds occurring between the 

 lowest eocene and the marine cretaceous deposits, which have 

 hitherto been classed with the Laramie formation of the Rocky 

 Mountains. The age of the firm grey sandstones and coal- 

 measures of the latter has long been doubtful, and they have been 

 variously described as secondary and tertiary. In the Denver 

 region, two beds are found overlying the Laramie unconformably, 

 the one consisting of a pebbly conglomerate, the other of debris 

 of andesitic lavas ; they have been termed the Denver and 

 Arapahoe formations respectively. Their equivalents have been 

 found in various other parts of Colorado. When, after the con- 

 tinental elevation which caused the retreat of the Laramie seas, 

 sedimentation began again, it was in comparatively small seas or 

 lakes. Succeeding the first period of lake-beds came a time of 

 great volcanic outbursts over a large area. The length of geo- 

 logic time occupied may not have been very great, but the extent 

 of country in which eruptions occurred at this time, and the great 

 variety of lavas found in the Denver and Middle Park regions, 

 argue for the decided importance of the event as a dynamic 

 manifestation. The writer wishes to advocate the restriction of 

 the term Laramie, in accordance with its original definition, to 

 the series of conformable beds succeeding the marine Montana 

 cretaceous, and the grouping of the post-Laramie lake beds in 

 another series, to which a comprehensive name shall eventually 

 be given. — On the alkali-metal pentahalides, by H. L. Wells 

 and H. L. Wheeler. With their crystallography, by S. L. 

 Penfield. An account of the preparation and properties of com- 

 pounds of the formula Csl,, CsBrg, CSCI.CI3I, RbCLCljI, 

 KCl.ClsI, NaCl.ClsLaHoO, LiCl.Cl3L4HoO. The first is 

 triclinic, the third, fourth, and fifth are monoclinic, and the Na 

 salt is orthorhombic. — Fossils in the "archaean" rocks of 

 Central Piedmont, Virginia, by N. H. Darton. Remains of 

 crinoids belonging to the upper Ordovician fauna \yere found in 

 the roofing slate of Arvon, Buckingham County, Virginia, which 

 has hitherto been classified as Huronian. — Notes on the Cambrian 

 rocks of Virginia and the southern Appalachians, by Chas. D. 

 Walcott. It is shown that towards the close of middle Cambrian 

 time, and during upper Cambrian time, there was a decided con- 

 tinental movement, resulting in the depression of the interior 

 continental plateau, and that this was accompanied by the for- 

 mation of conglomerates of the older Cambrian rocks in the valley 

 of the St. Lawrence, and by a great deposition of sediments of 

 later Cambrian time in the southern Appalachian region. — 

 Synthesis of the minerals crocoite and phoenicochroite, by C. 

 Ludeking, Ph.D. This was accomplished by exposing for 

 several months to the air a solution of lead chromate in caustic 

 potash in a flat dish. A mixture of the two kinds of crystals 

 resulted, which could be easily sorted by means of a pincette. — 

 A hint with respect to the origin of terraces in glaciated regions, 

 by Ralph S. Tarr. Tracing a resemblance between the flood 

 terraces of the Colorado in Texas, and the glacial terraces of the 

 Connecticut. — Occurrence of a quartz boulder in the Sharon coal 

 of north-eastern Ohio, by E. Orton.— A method of increasing 

 the range of the capillary electrometer, by John Whitmore. An 

 account of some experiinents performed in the Sloane Physical 

 Laboratory of Yale College, with a view towards improving the 

 mercury and sulphuric acid electrometer as constructed by Lipp- 

 mann and Pratt. Instead of having alternate bubbles of the two 

 liquids, the surface of the mercury exposed to oxygen polarization 

 was increased by blowing the tube into bulbs at the junction. A 

 series of bulbs was blown, spaced at equal intervals along a 

 capillary tube, the diameter of the bulbs being two centimetres, 

 that of the tube 06 mm. ; then the tube was so bent, that the 

 whole contained as many U-shaped parts as there were cells. 

 One arm of each U was provided with a bulb, which was situated 

 at a distance of two-thirds the height of the U from the base. 

 The apparatus was filled by connecting it with an aspirator, and 

 drawing in sufficient mercury to half fill each bulb, after which 

 dilute sulphuric acid was added by the same means. Platinum 

 electrodes were used, and the variations in the height of the 

 mercury columns produced by the E.M. F. examined, were read 

 by means of a cathetometer. The deflection produced by a 

 standard Clark cell was 3*20 mm. The range of the instrument 



is limited by the E.M.F. required to produce continuous electro- 

 lysis, but it was found that it could be considerably increased by 

 using a larger number of cells in series. It is possible to deter- 

 mine with this electrometer the E.M.F. of a cell correctly to 

 o'ooi of a volt. 



SOCIETIES AND ACADEMIES. 

 London. 

 Chemical Society, June 16. — Prof. A. Crum Brown, 

 F.R.S., President, in the chair. — The following papers were 

 read -.— Contributions to an international system of nomen- 

 clature. The nomenclature of cycloids, by H. E. Armstrong. 

 An account was given of the proceedings at the recent Con- 

 ference on Chemical Nomenclature at Geneva, and attention was 

 directed to the significance of the chief resolutions. A report of 

 the conclusions arrived at by the Conference has already 

 appeared in Nature (this vol., p. 56). — The production of 

 pyridine derivatives from the lactone of triacetic acid, by 

 N. Collie and W. S. Myers. The product of the 

 interaction of ammonia and triacetic lactone is most probably an 

 07-dihydroxy-o-picoline. By the action of phosphorus 

 oxychloride on this substance a compound possessing all the 

 properties of a dichloropicoline is obtained, and on passing this, 

 together with hydrogen, over heated zinc-dust, a-picoline boiling 

 at 128-129° is produced. The melting points of the platini- and 

 auri-chlorides, obtained from the synthetical alkaloid, agree with 

 those given by the corresponding compounds prepared from 

 pure a-picoline which was made by heating pyridine methio- 

 dide. — The fermentation of arabinose by Bacillus ethaceticus, by 

 P. F. Frankland and J. MacGregor. The products are 

 qualitatively the same as were obtained in the fermentations of 

 glycerol by the same organism, consisting of ethyl alcohol, 

 acetic acid, carbon dioxide, hydrogen, and traces of succinic 

 acid, together with another acid which was not identified. 

 When the fermentation is conducted in a closed space a notable 

 proportion of formic acid also occurs among the products. In 

 this case the products are formed approximately in the pro- 

 portions— sCjHfiO, 3C2H4O0, 4CH2O2, the formic acid as 

 well as the carbon dioxide and hydrogen found being all 

 collected together as formic acid in this statement. In the 

 fermentations conducted in flasks plugged only with cotton 

 wool, on the other hand, the alcohol and acetic acid were 

 formed in the proportion aCsHgO, 3C2H4O2. It appears, 

 therefore, that in the fermentation of arabinose by Bacillus 

 ethaceticus, the proportion of acetic acid to alcohol is greater 

 than in that of dextrose, and still greater than in the cases of 

 mannitol and glycerol, but less than in that of glyceric acid. — 

 Resolution of lactic acid into its optically active components, 

 by T. Purdie and J. VV. Walker The authors have resolves 

 ordinary inactive lactic acid into Isevo- and dextro-lactic acid 

 by taking advantage of the different solubilities of the strych- 

 nine salts of these components. Strychnine lievolactate is con- 

 siderably less soluble in water than the dextrolactate, although' 

 both salts may be crystallised. By fractional crystallization of 

 the mixed salts and subsequent removal of the strychnine from 

 the crystals and mother liquor, by means of ammonia or barium 

 hydrate, solutions were obtained which were respectively 

 dextro- and Isevo-gyrate. The dextrolactate yielded a zinc 

 dextrolactate having the same composition and solubility as 

 zinc sarcolactate. A well-defined dextro zinc ammonium salt 

 of the composition Zn.NH4 (0311503)3, 2H2O having the 

 specific rotatory power [o]d= -f-6"49 (approx.) was prepared. 

 The dextrogyrate salts yield a laevogyrate acid, which, like 

 sarcolactic acid, gives an oppositely active anhydride. The 

 quantities of oppositely active acids separated from each other 

 by means of the strychnine salts possessed equal amounts of 

 optical activity. Fermentation lactic acid is thus shown by 

 analysis to consist of two oppositely active isomeric acids, one 

 of which is identical with dextrogyrate sarcolactic acid, and the 

 other with the laevogyrate acid prepared by Schardinger by the 

 bacterial decomposition of cane sugar. — A new method for 

 determining the number of NH„ groups in certain organic 

 bases, by R. Meldola and E. M. Hawkins. In order to 

 ascertain the number of NHj groups present in certain organic 

 bases the authors propose to form the azoimides ; on atialysis of 

 these substances, the number of amidogen groups which have 

 been diazotized, can be determined. For example, paradiami- 

 doazobenzene(NH2. CeH4)2N2 was diazotized and converted into. 



NO. II 87, VOL. 46] 



