February 6, 19 13] 



NATURE 



^n 



which may be either Carboniferous or Permo-Carbon- 

 iferous. At the base of the Gondwana rocks are 

 glacial deposits to be referred to the same horizon 

 as the late Palaeozoic glacial deposits of Peninsular 

 India, the Salt Range, Australia, and South Africa, 

 but this horizon cannot be defined exactly. Its pre- 

 sence shows that the Raub Series must be older than 

 the Productus Beds of the Salt Range, or equivalent 

 to the shales below the boulder-bed in the trans-Indus 

 section of the Salt Range. The glacial deposits are 

 succeeded by littoral deposits, and far to the east of 

 the glacial deposits a Rhaetic horizon has been de- 

 scribed and named the Myophorian Sandstone. The 

 glacial deposits show that this portion of the Gond- 

 wanaland coast contained stanniferous granite and 

 also much corundum. Denudation has brought to 

 light the two anticlinal folds and the granite masses 

 upon which they now rest. On the west is the Main 

 Range Anticline, on the east the Benom Anticline. 

 The eastern limb of the former and the western limb 

 of the latter meet in the Main Range Foothills. The 

 eastern limb of the Benom Anticline is formed by tlie 

 main Gondwana outcrop. The igneous rocks of the 

 Benom Anticline are less acid than those of the Main 

 Range Anticline. The area of the Benom Anticline 

 coincides with the "gold-belt" of the peninsula. 

 Tertiary Coal Measures, unconformable on the Gond- 

 wana rocks, are known in Selangor. Their exact age 

 cannot be determined. Evidence has been found in 

 the peninsula supplementing the evidence described 

 by Dr. A. R. Wallace, of changes in the archipelago 

 in Tertiary times. When the land-connection that 

 allowed the migration of the fauna of the archipelago 

 from the north was destroyed by submergence, the 

 subsidence continued until the peninsula became an 

 island or group of islands. Subsidence then gave 

 place to elevation, which restored the peninsula. — 

 C. T. Trechmann : A mass of anhydrite in the Mag- 

 nesian Limestone at Hartlepool. The harbour of 

 Hartlepool owes its existence to the erosion of a mass 

 of anhydrite of great thickness, proved by boring to 

 exist in proximity to the Upper Magnesian Limestone 

 upon which the towns of Hartlepool and West Hartle- 

 pool are built. The anhydrite is included in, and 

 represents the time-equivalent of part of, the Middle 

 and part of the Upper Limestones. The former pre- 

 sence of sulphates in the Magnesian Limestone is 

 discussed. Evidence is brought to show that quanti- 

 ties of anhydrite were originally deposited with the 

 Magnesian Limestone, the subsequent hydration and 

 removal of which are responsible for the collapse, brec- 

 ciation, and other alterations that are features of the 

 present formation. The distribution of organisms in 

 the Magnesian Limestone was influenced by the sul- 

 phates present in the water. The Shell Limestone 

 is a chain of reef-knolls. The curious distribution and 

 present position of the Upper Magnesian Limestones 

 in Durham is noticed, and an explanation offered. 

 The Permian succession is shown to be more com- 

 plete in the southern than in the northern area of the 

 county. Various sections in the Upper and Upper 

 Middle Limestones in the Hartlepool area are 

 described. 



Linnean Society, January i6.— Prof. E. B. Poulton, 

 F.R.S., president, in the chair. — Prof. E. L. Bonvier : 

 Les Caridines des Seychelles, avec des observations 

 sur leurs variations. — Rev. \. E. Eaton : (i) Psychodidae 

 of the Seychelles. (2) Ephemeridae of the Seychelles. 

 — H. Campion : Odonata of the Seychelles. — W. A. 

 Harding : A new land leech from the Seychelles. 



Physical Society, January 24. — Prof. C. H. Lees, 

 F.R.S., vice-president, in the chair. — S. W. J. Smith 

 and H. Moss : The resistance of electrolytes. In ex- 



XO. 2258, VOL. 90] 



periments described in lyii a modilication of Wien's 

 method was used — the optical telephone being re- 

 placed by a vibration galvanometer — and the conclu- 

 sion was drawn that the resistance of an electrolyte 

 varies to an easily perceptible degree with the fre- 

 quency of the alternating currents to which it is sub- 

 jected. It is unsound to use the method to test 

 whether the resistivity of an electrolyte depends upon 

 the frequency of the currents to wliich it is subjected, 

 unless it is shown that the effects of leakage through 

 the electrolytic condensers can be neglected or allowed 

 for. In order to remove or justify any doubt upon 

 the question test experiments have been performed. 

 The method depends upon simultaneous measurement 

 of the voltage between the ends of a tube containing 

 the electrolyte and of the current passing through it. 

 It was found that the resistivity of the electrolyte was 

 constant within 0-05 per cent., whether steady currents 

 or currents of any frequency up to 2300 alternations 

 per second were used. Until the instruments were 

 calibrated there appeared to be a small difference of 

 about I part in 600 between the resistance as measured 

 by continuous currents and the values obtained with 

 alternating currents. Some experiments were made 

 with the object of elucidating the behaviour of the 

 instruments which this calibration disclosed. The 

 fact that the apparent contact P.D. within the volt- 

 meter was a function of the applied voltage, decreas- 

 ing as the latter was raised, would cause an effect of 

 the same sign as that observed. Unallowed-for 

 leakage, greater with steady than with alternating 

 currents, might also provide a partial explanation of 

 the results. — W. S. Tuclier : The electrical conductivity 

 and fluidity of strong solutions. In adopting Cal- 

 lendar's association theory of strong solutions diffi- 

 culty is experienced in getting the strongest solutions 

 of electrolytes to conform to the laws. This is attri- 

 buted to the inaccuracy of the ionisation data. It 

 may be supposed that the viscosity of the solution 

 will affect its conductivity, and experiments to deter- 

 mine if there were any relation between conductivity 

 and fluidity in the case of calcium chloride solutions 

 were carried out. The feature is the simultaneous 

 observation of viscosity, electrolytic resistance, and 

 temperature. Solutions w'ere contained in an un- 

 silvered Dewar cylinder. A platinum thermometer 

 records the temperature. W'hile the thermometer 

 oscillates the readings of electrical resistance were 

 measured. The viscometer was in the form of a 

 capillary pipette immersed in the solution to a known 

 depth. Viscosities correct to less than i per cent, 

 were obtained. Perfectly smooth curves for conduc- 

 tivity and fluidity were obtained. No connection 

 between conductivity, fluidity, and concentration can 

 be derived if the last is expressed in terms of 

 volume, but if concentration is expressed as a ratio 

 of masses — molecules of solute to 100 molecules of 

 solvent — the ratio conductivity C/fluidity F stands in 

 linear relation to the concentration n when the latter 

 exceeds one-fourth its maximum value. One solution 

 of nearly crvohydric strength was examined at tem- 

 peratures from 40° C. to —50° C. The failure of the 

 fluidity-temperature and conductivity-temperature 

 curves to exhibit the same variations was shown. 

 Conductivities of solutions were examined from 40° C. 

 to their freezing points and the curves C/n and tem- 

 perature plotted. The increasing curvature with con- 

 centration is shown, and the error involved in apply- 

 ing the ratio, molecular conductivity to that at infinite 

 dilution, obtained at one temperature, to indicate 

 ionisation at another temperature, is quite apparent. 

 The results obtained suggest that no dependence 

 can be placed on ionisation data derived from electrical 

 conductivity observations. 



