March io, 19 io] 



NATURE 



59 



ues of Cj and Cj for the sodium, thallium, and lithium 

 ;s only, obtained by quite a different method. The 

 fficients C,, Cj are found to be negative, so that both 

 s are accelerated by tension, but the effect is much 

 *er for Cj, i.e. for the ray polarised in the direction of 

 jss. With regard to the dispersion in O. 935, both Ci 

 I Cj show a slight general decrease as we move towards 

 violet, but in VV. 3199, Cj show^s a decrease, whereas 

 shows an increase. The above general variation is 

 ken by a number of local oscillations, some of which 

 well marked and confirm previous observations of 

 — C} (Phil. Trans., A, vol. ccvii., pp. 293-301), whilst 

 ers are more doubtful ; but it seems probable that both 

 ices of refraction due to stress are affected locally by 

 ; periods of the constituents of the glass, causing 

 jgularities in the curves of C, and C^ similar to those 

 libited by the curve of the index of refraction in 

 )malous dispersion. 



loyal Microscopical Society, February 16. — Prof. J. A. 

 omson, president, in the chair. — Prof. J. A. Thomson : 

 tes on Dendrobrachia fallax, a rare and divergent anti- 

 harian. — A. A. C. E. Merlin : The measurement of the 

 t nine groups of Grayson's finest twelve-band plate. — 

 H. Collins : The labelling of microscopic slides. 



Cambridge. 

 Philosophical Society, February 7. — Prof. W. Bateson, 

 I.S., president, in the chair. — E. A. Newell Arbor: 

 note on some fossil plants from Newfoundland. Two 

 V records from Newfoundland, either of Lower 

 rboniferous or Upper Devonian age. The first appears 

 be Sphenophyllum tenerrimum, Stur., both leaf whorls 

 I stems being preserved. The second is a large fan- 

 iped leaf, probably new specifically, which recalls the 

 laeozoic fossils attributed to the genus Psygmophyllum. 

 V. T. Gordon : The relation between the fossil 

 mundaceae and the Zygopterideae. The members of the 

 ^opterideae and Osmundaceae are shown to exhibit 

 allel development, and their most primitive genera, 

 ^opteris Romeri, Solms, and Thamnopteris Schlechten- 

 ii, Eichwald, respectively, are compared as regards the 

 Licture of the stem and the origin of the petiole to 

 nonstrate an ancestral relationship between these groups. 

 V. T. Gordon : A new species of Physostoma from the 

 wer Carboniferous of Pettycur (Fife). A new seed, 

 iwing a number of tentacular processes at the apex and 

 outer coat studded with small peg-like hairs. This is 

 most ancient example of the genus known. — Mrs. E. A. 

 well Arber : A note on Cardiocarpon compressuni, 

 11. The results of a re-examination of a Coa'-measure 

 d originally figured and described by Williamson in 

 7 under the name of Cardiocarpon compressum. — 

 Hamshaw Thomas : The assimilating tissues of certain 

 il-measure plants. Some points in the structure of the 

 ves of Calamites, Lepidophloios, and other Coal-measure 

 nts from the point of view of their physiological 

 itomv. — L. J. Wills : Notes on the genus Schizoneura. 

 limper and Mougeot. A description of examples of 

 moneura paradoxa, S. and M., recently discovered in 

 Keuper of Bromsgrove (Worcestershire), and a com- 

 [ative review of other members of the genus. — R. D. 

 knon : The occurrence of Schizoneura paradoxa, S. and 

 in the Bunter of Nottingham. — D. G. Lillio : 

 !rified plant remains from the Upper Coal-measures of 

 stol. Petrified material of Cordaites and other allied 

 era, and also of Myeloxylon, has been obtained from 

 Upper Coal-measures of Staple Hill, Bristol. 



Manchester. 



iterary and Philosophical Society, January 25. — 



Francis Jones, president, in the chair. — Prof. W. W. H. 



i and F. Brotherton : The electrical resistance of the 



nan body. Measurements have been made with direct 



alternating currents, the hands of the subject being as 



ule immersed in solutions of common salt. Values of 



resistance in the first case are from 1000-2000 ohms, 



only from 700-800 ohms with alternating currents. The 



h values in the first case are due to polarisation, th" 



nan body acting like a storage battery made up of con- 



tration cells. When a direct current is applied to the 



y the current falls for a time and then increases, there 



NO. 2106, VOL. 83] 



being a gradual increase of polarisation during the first 

 period, and a decrease of the body resistance during the 

 second period. The maximum voltage for direct currents used 

 in the experiments was about 40, which mut be gradually 

 introduced, and very gradually withdrawn, otherwise painful 

 shocks are administered. It was found that the resistance is 

 inversely proportional to the area of the surface of the wet 

 skin. The ratio of the direct to the alternating values of 

 the resistance is much higher when dry or nearly dry skin 

 is tested. With the dry fingers applied to loo-volt direct 

 current terminals the shock at the kathode is greater than at 

 the anode, and enables the polarity of the terminals to be 

 readily determined. With nearly dry fingers it is also t&sy 

 to test polarities of circuits of less than 20 volts. This 

 method is useful in practice. With about 10 volts and the 

 fingers immersed in salt solutions containing metal elec- 

 trodes, the body can be used as a telegraphic receiving 

 instrument, the shocks at the kathode as the current is re- 

 versed by a transmitting commutator enabling messages to 

 be received by the usual code. The resistance of the body 

 being relatively low when the skin is moist, precautions 

 must be taken in using supply circuits, especially in 

 chemical and other works. Electric-light fittings in bath- 

 rooms, public baths, and medical baths require special 

 precautions. 



February 8. — Mr. Francis Jones, president, in the chair. 

 — G. Hicklingr : The anatomy of C alamo stachys 

 Binneyana, Schimper. It was shown that the so-called 

 " nodes " at which the sporangiophores arise are not true 

 nodes. There is no secondary xylem at that level, the 

 protoxylem canals are not obliterated, no " gaps " are 

 seen in the cauline bundles, and the medulla is not modified 

 as at the true node. The slender vascular traces supplying 

 the sporangiophores may be arched before entering them. 

 Below the sporangiophore the traces may occasionally be 

 seen lying on either side of the corresponding cauline 

 bundle, often freed from it by maceration. There is con- 

 siderable evidence to show that the sporangiophore trace 

 preserves its identity down to the subjacent true node. The 

 axes, which are commonly described as possessing six 

 bundles in three pairs, are shown to possess only three 

 single bundles. Both three and four bundles are proved by 

 serial sections to characterise different parts of the same 

 cone. There is some evidence that the alternation of the 

 bracts has been brought about by their lateral displace- 

 ment. It was shown to be possible to obtain good series 

 of sections by grinding the blocks containing the material 

 and taking photomicrographs of the successively exposed 

 surfaces. — L. E. Adams : A hypothesis as to the cause 

 of the autumnal epidemic of the common and the lesser 

 shrew. The fact that more corpses of shrews are found 

 in autumn than during the other seasons of the year has 

 been a standing puzzle to naturalists, and no wholly satis- 

 factory explanation has hitherto been suggested. The 

 known agencies of destruction, such as conflicts among 

 themselves, attacks of enemies, scarcity of food, and 

 drought, whilst resulting in many deaths, fail to account 

 for the sudden rise in mortality during the autumn. The 

 author, as the result of observations and investigations 

 carried out during a number of years, is decidedly of the 

 opinion that the autumnal "epidemic." as it is called, is 

 due to nothing more than old age, old age in the case of 

 the common and the lesser shrew being reached in, roughly, 

 thirteen or fourteen months. This conclusion is supported 

 by the fact that all specimens of the common and lesser 

 shrew trapped during and after December in a series of 

 years were found to be immature. This hypothesis would 

 account also for the absence of wounds and other marks 

 of violence in many of the corpses found. 



Roval Meteorological Society, February 23. — Mr. H. 

 Mellish, president, in the chair.— Dr. W. Makower, 

 A. J. Makower, and Miss M. White : Investigation of 

 the electrical state of the upper atmosphere made at the 

 Howard Estate Observatory, Glossop. — A. W. Harwood : 

 The results of twenty-five registering balloon ascents made 

 from Manchester on' June 2-3 last. These were sent up 

 at intervals of one hour, and some extremely interesting 

 and valuable results were obtained from them. — R. G. K. 

 Lempfert and R. Corless : Line squalls and associated 

 phenomena. 



