June 12, 1919] 



NATURE 



297 



describes a new species of Lichas from the Wenlock 

 l.imestone and a new variety of Calymene papillata. — 

 Dr. A. Gilligan : The petrography of the Millstone 

 ' ii it series of Yorkshire. Since the pioneer work of 

 >orby on this subject, published in 1859, the clastic 

 deposits of the Carboniferous system have been un- 

 accountably neglected by petrologists. The author has 

 followed the usual methods of investigation, and 

 collected a large number of pebbles and specimens 

 from widely separated areas, which have been examined 

 microscopically. Numerous separations of the heavy 

 minerals have also been made from all types of rock, 

 varying from coarse conglomerates to shales, which 

 occur in the series. In Yorkshire the Millstone Grit 

 forms the surface of 840 square miles ; while, if that 

 .which lies beneath the newer rocks and that repre- 

 sented by outliers on the Pennine Fells were taken 

 into account, it must have extended over at least 

 2000 square miles. If 1000 ft. be taken as its average 

 thickness, the Y'orkshire Millstone Grit would repre- 

 sent a volume of 400 cubic miles, the equivalent of a 

 range of mountains 800 miles long, i mile high, and 

 I mile wide at the base. The author shows that the most 

 (probable source of the material lay in a land-mass 

 of continental extent, of which Scandinavia and the 

 North of Scotland represent the remaining fragments. 

 In these areas alone can the mineralogical demands 

 of the Millstone Grit be satisfied, and the author in- 

 stitutes a comparison between the Torridon Sand- 

 stone and the Millstone Grit, which shows that their 

 similarity of constitution is altogether too great to 

 be merely fortuitous. He infers that, despite their 

 disparity in age, they had a common source in that 

 northern continent. 



Society of Glass Technology, May 2i.^Dr. M. W. 

 Travers in the chair. — Dr. W. Rosehhain : Some pheno- 

 mena of pot attack. Research was begun on the 

 improvement of methods for the production of optical 

 glass. The first step was to find a material to arrest 

 the attack of molten glass, and to endeavour, if 

 possible, to discover a container entirely insoluble in 

 glass at high temperatures. A study of glass attack 

 upon clay was begun, and the process by which glass 

 attacks clay investigated. These processes, owing to 

 the novel methods used, could be carefully controlled 

 under standardised conditions. Small pots made of 

 china clay cast bv a special method were used in the 

 research. The furnace was an electrical one, so 

 constructed that temperature and atmosphere could 

 be kept constant. The pot attack of several glasses 

 known to be very violent in their action upon clay 

 was studied. The amount of pot attack was measured 

 exactly under various time and temperature condi- 

 tions. The result showed that the attack was mainly 

 on the bottom of the pot, and that holes were drilled 

 in a rough, circular form. In many cases it was 

 shown that the amount of attack was proportional to 

 the depth of the clav beneath the glass surface. The 

 explanation of the results was somewhat difficult to 

 find, but a study of the solution of solids in liquids 

 less viscous than glass led to the conclusion that the 

 phenomenon was due to currents set up in the liquid 

 by density changes. One of the portions of the 

 research had been the microscopic examination of the 

 glass and pot after attack. This portion of the work 

 is still in progress. It had been proved conclusively 

 that holes could be drilled in a pot without having 

 actual defects in the pot to start with. Another very 

 interesting feature recently developed was the applica- 

 tion of X-rays to the examination of small pots. 



Zoological Society, May 27.— Dr. A. Smith Wood- 

 ward, vice-president, in the chair. — J. T. Cunningham : 

 Result of a Mendelian experiment on fowls, including 

 the production of a pile breed. — Miss Kathleen F. 



NO. 2589, VOL. 103] 



Lander: Some points in the anatomy of the Takin 

 {Budorcas taxicolor 'whitei).—E. Phelps Allis : Certain 

 features of the otic region of the chondrocranium of 

 .Lepidosteus, and comparison with other fishes and 

 higher Vertebrata. 



Aristotelian Society, June 2.— Lord Haldane in the 

 chair.— Dean Inge : Platonism and human im- 

 mortality. The Platonic doctrine of immortality rests 

 on the independence of the spiritual world. The 

 spiritual world is not a world of unrealised ideals 

 over against a real world of unspiritual fact. It is, 

 on the contrary, the real world, of which we have a 

 true, though very incomplete, knowledge, over against 

 a world of common experience which, as a complete 

 whole, is not real, since it is compacted out of mis- 

 cellaneous data, not all on the same level, by the help 

 of the imagination. There is no world corresponding 

 with the world of our common experience. Nature 

 makes abstractions for us, deciding what range of 

 vibrations we are to see and hear, what things we 

 are to notice and remember. It is the substantiation 

 and continuance of this makeshift construction that 

 we are sometimes childish enough to desire. What 

 is real in it is the thought of God transmuted into 

 vital law. The operation of these forces we study 

 mainly in transverse sections, since we have forgotten 

 most of the past and are ignorant of the future. But 

 since the soul is a citizen of the eternal world, we can, 

 if we will, "be eternal in the midst of time," though 

 our higher life is for most of us fitful, indistinct, and 

 confused. It follows that salvation, for the Platonist, 

 must be deliverance from a world of shadows and 

 half-truths, per tenebras in lucem. 



Cambridge. 

 Philosophical Society, May 19.— Mr. C. T. R. Wilson, 

 president, in the chair.— F. W. Aston : The use of 

 neon lamps in technical stroboscopic work. The 

 standard method of calibrating and testing revolution 

 indicators for aero-engines is by means of a strobo- 

 scopic disc or cylinder illuminated by flashes of a 

 neon lamp. The'latter is lit by a small induction coil 

 interrupted exactly fifty times per second by a standard 

 electrically driven tuning-fork. Neon tubes of the 

 ordinary spectrum type give a flash of considerable 

 duration, some thousandths of a second, and there- 

 fore are' unsuitable. This flash when analysed by 

 a rotating mirror is found to consist of a single prac- 

 tically instantaneous flash followed by a flame or arc. 

 Bv rneans of a special form of lamp the whole of the 

 energy of the discharge can be thrown into the first 

 flash," the duration of which has so far defied measure- 

 ment, and is certainly less than one ten-millionth 

 of a second, making it ideal for stroboscopic work. 

 By illuminating an engine running at full speed by 

 means of such a lanip arranged to give 99 flashes per 

 100 revolutions of the crank-shaft, the engine will 

 appear to rotate at one-hundredth its real speed, so 

 that the most minute observations on its moving parts 

 can be made. This method has also been extended 

 to the examination of air-screws for strains when 

 running at high speeds.— F. W. Aston : The distribution 

 of intensity along positive-ray parabolas of atoms and 

 molecules of hydrogen, and' its possible explanation. 

 This paoer deals with the bright arcs or "beads" on 

 the positive-rav parabolas of hvdrogen which corre- 

 spond with half the normal energy, and therefore can- 

 not be due to multiple charges. Experiments seem to 

 indicate that 'the discharge can be separated into two 

 types. In the fir^t or "atomic" type, which can be 

 obtained practically pure under certain conditions. 

 it seems possible that the whole discharge is carried 

 up to the cathode bv ions of atomic mass. The pro- 

 posed explanation of the bright arc on the molecular 



