y^me 26, 1879] 



NATURE 



211 



occurred at great depths, a fact which showed that the sea-bed 

 in that part of the Mediterranean had been considerably raised 

 since the tertiary epoch. — Mr. Edward R. Alston read a note 

 on the Acanthomys leucopus of Gray, showing that it does not 

 belong to the genus Acanthomys but to Mus proper. As the 

 name leucopus is pre-occupied in the latter genus, he proposed to 

 call the species Mus term regina:. — Mr. W. L. Distant read a 

 paper on the African species of I.epidoptera of the genus 

 Papilio. A new species from Magilia, East Africa, was de- 

 scribed, and the name of Pafilio hornitnani was proposed for it. 

 — A communication was read from the Count T. Salvkdon, 

 C.M.Z.S., containing further particulars of the new Pheasant 

 from Western Sumatra which he had recently described as 

 Acomus inornitus. — Messrs. Godman and Salvin gave an account 

 of some hitherto unrecorded diurnal lepidoptera, obtained by 

 the Rev. George Brown in Duke of York Island and New 

 Ireland, together with descriptions of some ajiparently new 

 species. — A communication was read from Mr. F. Jeffrey Bell, 

 being the second of the series of his observations on the 

 characters of Echinoidea. The present paper contained an 

 account of the species of the genus Tripneustes. — Messrs. 

 Sclater and Salvin read a paper on the birds of Bolivia, based 

 principally upon an examination of the specimens obtained by 

 Mr. Buckley duing two expeditions into that country. 



Geological Society, June 11. — Prof. Joseph Prestwich, 

 F.R.S., vice-president, in the chair. — Noel W. Rudstone Read, 

 was elected a Fellow; and M. Edouard Dupont, of Brussels, 

 Dr. Franz von Kobell, of Munich, and Dr. Emile Sauvage, of 

 Paris, Foreign Correspondents of the Society. — The following 

 communications were read: — On a mammaliferous deposit 

 at Barrington, near Cambridge, by Rev. O. Fisher, F.G.S. 

 The gravel in which these remains were found is about 20 feet 

 above the alluvial flat by the River Rhee, and is evidently post- 

 glacial. The gravel contains some of the ordinary land and 

 fresh-water shells, but not Cyrena or Unio. Remains of the 

 following mammalia have been found: — Ursus spehrus, Meles 

 taxus, Ilycena spelaa, Felis speltra, Cenius inegaceros, elephus, 

 and another, Bos primigenius. Bison priscus, Ilippopotamits 

 major, Rhinoceros leptorhinus, Elephas anttquus and primi- 

 genius, with a worked flint, almost certainly from the same 

 deposit. The author considers the abundance and admixture of 

 these remains due to the locality having been a sort of eddy or 

 pool in the old river. The remains are described, and the rest 

 of the paper is occupied with a correlation of the gravel with 

 others in the adjoining district, and a consideration of the 

 physical conditions under which it was deposited. —Further 

 discoveries in the Cresswell Caves, by Prof. Boyd Dawkins, 

 F.R.S., and the Rev. J. M. Mello, F.G.S., with notes on the 

 mammalia by the former. This paper contained the account of 

 digging-operations carried on in one of the smaller caves of the 

 Cresswell Crags, known as Mother Grundy's Parlour. The 

 authors described the occurrence in the red clay and ferruginous 

 sand of this cave of bones of hippopotamus and the leptorhine 

 rhinoceros, proving the existence of these animals in the wooded 

 valleys of the basin of the Upper Trent at the time of the accumu- 

 lation of those deposits ; while at the same time, so far as the 

 evidence goes, there was an absence of palaeolithic man, of the 

 reindeer, and of horses, while hysenas were abundant. In a 

 subsequent period, represented in all the caves by the red sand, 

 the mammoth, woolly rhinoceros, horse, and reindeer in- 

 habited the vicinity, and were subject to the attacks both of 

 hyaenas and of human hunters, whose quartzite implements 

 prove them to belong to the same people whose traces are 

 found in the river-deposits. In the breccia and upper cave-earth 

 of the larger caves the existence of the pala:olithic hunter is 

 evidenced by flint implements, resembling those of Solutre, accom- 

 panied by implements of bone and antler. Associated with these 

 was the incised figure of a horse described in a former paper. 

 The authors finally dwelt briefly upon the characteristics of the 

 caves in prehistoric and historic times, and indicated some of 

 the anthropological points of interest connected therewith. — 

 On the pre-Cambrian rocks of Shropshire, part i, by C. 

 Callaway, F.G.S. — On the occurrence of a remarkable, 

 and ap])arently new mineral in the rocks of Inverness-shire, 

 by William Jolly, F.R.S.E., H.M. Inspector of Schools, and 

 J. Macdonald-Cameron, Fel. Inst. Chem., F.C.S. In this paper 

 the authors refer to a blue mineral of a somewhat remarkable 

 character, noticed at Englishton Moor and neighbourhood, distant 

 westwards, from Inverness, about S miles, where the mineral 



occurs in scattered blocks. It has since been noticed at Moniack 

 Burn, Reelig Glen, and South Clunes Farm, all in the same 

 direction, but distant from Inverness about lo miles ; also near 

 Dochfour House, at the north end of Loch Ness, close by 

 Dochgarroch Lock of the Caledonian Canal. In colour and 

 general appearance this mineral resembles crocidolite, but 

 analyses point to its being more nearly related to jcgirite, a 

 member of the amphibole group, which has the general formula 

 Si3(J5 + R3). The mean of several analyses shows it to have 

 the composition 6Si02, Fe20.3, 2MgO. 



Physical Society, June 14. — Prof. W. G. Adams in the 

 chair. — New Members: Donald Macalister, B.A., and Mr. St. 

 George Lane Fox. — ^Prof. Macleod described a plan for sup- 

 pressing the induction disturbances in a telephone circuit. It is 

 known that a secondary battery composed of metal plates and 

 sulphuric acid allows weak currents to pass while stopping 

 those of high tension. Prof. Macleod inserted a secondary 

 battery of platinum plate between the line and the telephone, 

 but this stopped both the induction and the vocal currents. 

 When platinum wires were substituted for the plates, however, 

 the induction-currents were stopped, while the vocal cm-rents 

 could be feebly heard. — Dr. O. J. Lodge exhibited his new 

 reversing key for electrometer work, which is preferred to the 

 ordinary forms as giving a high insulation, small capacity, 

 and not requiring the hand to approach close to it to 

 work it. It consists of four platinum wires arranged in pairs 

 crossing one another, one pair crossing between the other two. 

 These are the terminals and contact pieces of the key. 

 The middle pair are supported by an endless silk thread 

 which runs on two pulleys, one of which is fitted vpith a 

 handle. On turning the handle to right or left the two 

 middle wires are brought into contact with one or other 

 of the two outer wires, and the current reversed at will. The 

 whole is inclosed in a metal box. — Mr. J. F. Moulton then 

 demonstrated the results of the experiments of Mr. Spottiswoode 

 and himself on the sensitiveness of electric discharges in vacuum 

 tubes. These experiments were undertaken to find the cause of 

 the luminous layers or strata in the discharge, a Holtz machine 

 being employed. It was observed that when feeble currents 

 were drawn from the machine, the discharge could be depressed 

 by laying the finger on the tube, and this depression always 

 occurs with intermittent currents, therefore the feeble currents 

 form a continuous current Holtz discharge themselves, like inter- 

 mittent currents, by reason of their feebleness. This sensitive- 

 ness of the discharge to the approach of the finger was found to 

 be due to the conductivity and electric capacity of the hand. 

 Electricity opposite in kind to the discharge is induced on the 

 finger, and streaming upon the tube, neutralises part of the 

 discharge therein. This effect was also shown by means of 

 tinfoil rings rrund the tube. An intermittent current is of course 

 capable of this static induction on neighbouring conductors. 

 The luminous discharge in a vacuum-tube consists of a bright 

 sharp glow at the ne?ative terminal, followed by a dark space, 

 then a hazy bluish light at the positive pole. The strias or 

 layers in these sensitive tubes merely repeat this appearance. They 

 can be artificially produced by placing the fingers, or rings of metal, 

 at intervals along a tube conveying an amorphous discharge ; for 

 in this case the induced electricity discharging itself from the 

 fingers, breaks up the amorphous discharge into dark and bright 

 layers. In these stratified discharges the electricity appears to 

 travel per saltum, or by stepping-stones, as one may say, and the 

 glow seems to be a molecular stmcture, a view which is sup- 

 ported by Mr. Crookes's experiments. A negative discharge 

 from the finger produces a dark space in the tu e discharge, and 

 a positive one a bright hne ; therefore one can tell the kind of 

 discharge passing in a tube by laying a finger on it. If the same 

 pole be brought to both ends of a tube a discharge will still take 

 place from each end, and there will be a dark space in the middle, 

 the electricity here seeming to turn back again the way it came. 

 The discharge from a pole through a vacuum tube would there- 

 fore appear to be not akin to conduction, but to a (iisruptive dis- 

 charge. It is a leap in the dark, and the phenomena obsen,'ed 

 are due to the gaseous nature of the medium. These experi- 

 ments point to the possibility of completing a ci cu.t by positive 

 electricity alone. Prof. Guthrie suggested that by combining 

 vacuum-tubes with the conduction-balance of Prof. Hughes it 

 might be possible to get an optical balance for measuring induc- 

 tive capacity.— Dr. Henry Draper, of New York, who is now 

 on a visit to England, then addressed the meeting on his alleged 



