July 6, 191 1] 



NATURE 



33 



Spencer : The larger diamonds of South Africa. | 

 Historical notes relative to the "Excelsior," "Jubilee," 

 and " Imperial " diamonds were given, together with a 

 tabular statement of the weights of the rough and cut 

 stones in carats and grams, and the percentage yield of 

 the cut brilliants from the rough. — F. H. Butler : Breccia- 

 tion in mineral veins. In vein-breccias due to fracture 

 in situ (crush-breccias) replacement of country-rock is a 

 characteristic feature. Where the coarse fragments in a 

 brecciated fissure-vein indicate erosion, removal of fine 

 rock debris may be inferred. Fragments that are angular 

 and uneroded and completely isolated by encrusting 

 material often indicate by shape and position their former 

 existence as a single mass. The quiet removal of such 

 fragments into a vein-cavity after reunion, and also the 

 banding, with concomitant contortion of adjoining soft 

 country-rock, by their cement-substance, may be ascribed 

 to the hydrostatic pressure and the solvent and mineralising 

 properties of the waters which furnished that substance. 

 The coarse constituents of breccia may have been crushed 

 in situ, or forced from fissure-walls by earth movements, 

 or detached therefrom by aqueous pressure and solution. — 

 Arthur Russell : Prehnite from the Lizard district. Two 

 distinct types of crystals, tabular and prismatic, were 

 recently found by the author on hornblende-schist at Pare 

 Bean Cove, Mullion, Cornwall, the former showing the 

 forms 001, 302, 061, and the latter ioo, ooi, no, 061, and 

 the rare form 301. 



Royal Meteorological Society, June 14. — A.J. Makower, 

 \Y. Makower, W. M. Gregory, and H. Robinson : 



Investigation of the electrical state of the upper atmo- 

 sphere. The object of the experiments described was to 

 measure the electrostatic potentials at various heights 

 above the ground and the currents that flow down an 

 earthed kite-wire. The method adopted was to send up 

 kites or, in still weather, balloons attached to steel wires, 

 provision being made for detaching sections of the wire 

 from the winding drum so that the lower end might be 

 anchored to a long rod of ebonite in order to insulate it 

 from the ground. When this had been done the wire 

 could either be earthed through a galvanometer to measure 

 the current flowing down the wire, or else be connected 

 to an electrostatic voltmeter having a range of 100,000 

 volts by means of a metallic line passing through glass 

 tubing supported on long insulators to prevent brush dis- 

 charges to the surrounding air or leakage to earth. 

 Curves are given embodying the results of a series of 

 flights made during the month of August, 1910, the poten- 

 tials and currents that were measured being plotted as 

 functions of the heights above the ground. The values 

 obtained for the potential gradient near the ground lie 

 between 05 and 1-5 volts per centimetre, and are in 

 agreement with those deduced from the tests of previous 

 experimenters using water-droppers or radium collectors, 

 but it is found that the potential gradient diminishes 

 rapidly as the height above the ground increases. Flights 

 are recorded up to 4000 feet above the ground, at which 

 height the potentials ranged between 40,000 and 60,000 

 volts, and the currents between 40 and 100 microamperes. 

 Measurements were also made of the time taken by the 

 kites and balloons to attain the full potential of the 

 surrounding air from the moment at which the wire was 

 disconnected from earth. This rate of charging is of 

 interest in aeronautics in connection with the devising of 

 suitable methods of preventing dangerous electric dis- 

 charges from taking place between a balloon and the 

 surrounding medium after a sudden change of height. 

 The tests showed that the kites and balloons, the collect- 

 ing area of which was about 150 square feet, charged up 

 according to an exponential law, the exponential coefficient 

 having values lying between 01 and 0-23, showing that 

 a potential of half the full value was reached in about 

 5-5 to 7 seconds. It is argued that the rate of charging 

 up is probably proportional to the radius of the balloon, 

 and so the rate of charging up of large passenger balloons 

 might be deduced from the rates determined with the 

 small balloons used in these investigations. Attempts 

 were made by the authors to discover a connection between 

 the electrical state of the atmosphere and the prevailing 

 temperature, barometric pressure, humidity, and wind 



NO. 2175, VOL. 87] 



velocity as registered on self-recording instruments sent up 

 at each flight, but it was found that the amount of data 

 collected was not sufficient to make such deductions 

 possible. It seems that such conclusions will not be able 

 to be drawn until continuous experiments extending over a 

 considerable period of time have been made. 



Geological Society, June 14. — Prof. W. W. Watts, 

 F.R.S., president, in the chair. — Prof. W. S. Boulton : 

 A monchiquite intrusion in the Old Red Sandstone of 

 Monmouthshire. An unrecorded monchiquite, intruded 

 into the Upper Old Red formation of Monmouthshire, is 

 described. The manner of its intrusion is doubtful. The 

 disturbance and metamorphism of the contact-rocks are 

 dealt with, as also the rounded lumps of marl and sub- 

 angular chips of sandstone incorporated in the igneous 

 rock. The monchiquite contains large phenocrysts of 

 augite and biotite, generally much corroded. Rounded 

 " nodules " of olivine-augite rock with chromite are also 

 included. A second generation of augite, biotite, and 

 decomposed olivine occurs porphyritically in the ground- 

 mass. The ground-mass is a felt of minute elongated 

 augite prisms, magnetite grains, and flakes of biotite. A 

 complete analysis of the rock is given, which bears out 

 the petrographical evidence that it is a very basic lampro- 

 phyre belonging to the monchiquite group. Its age and 

 connection with the only other known intrusion into the 

 Old Red Sandstone of the South Wales area are referred 

 to. — Notes on the Culm of South Devon : Part i. — Exeter 

 district, by F. G. Collins, with a report on the plant- 

 remains by E. A. N. Arbor, and notes on the Cephalopoda 

 by G. C. Crick. The paper is to show that the fauna of 

 the Culm Measures of South Devon proves these beds to 

 be the equivalents of the Pendleside series of the Mid- 

 lands. The actual fossiliferous localities are eighteen in 

 number, but often the fossils are too poor for determina- 

 tion. It seems advisable to seek more evidence, and an 

 attempt will be made by working due north from Waddon 

 Barton, a point farther to the west. 



British Psychological Society, June 24 (held at Man- 

 chester).— Dr. T. Graham Brown : Note on the percep- 

 tion of movement in the environment. — C. Burt : The 

 experimental investigations of emotional dispositions. — Dr. 

 H. Watt : A new classification of experiences. — Prof. 

 C. S. Sherrington : A simple teaching apparatus for 

 illustrating Listing's law.— Prof. J. Lorrain Smith and 

 Dr. W. Mair : A chemical comparison of the brain sub- 

 stance of the child and the adult. 



Dublin. 

 Royal Irish Academy, June 26.— Rev. Dr. Mahaffy, presi- 

 dent, in the chair.— C. F. Rousselet : Clare Island 

 Survey : rotifera. Mr. Rousselet collected all the rotifera 

 except the Bdelloida, which are embodied in a special re- 

 port by Mr. James Murray. The report shows that the 

 rotifer fauna of Clare Island and the neighbouring parts 

 of the mainland differs in no special features from that of 

 many other parts of the British Islands. Mr. Rousselet 

 gives a list of 103 species with their distribution. Some 

 of these had not previously been recorded from the British 

 Islands.— Eugene Penard and G. H. Wailes : The fresh- 

 water rhizopoda obtained during the Clare Island Survey. 

 The first collections of the fresh-water rhizopoda of Clare 

 Island and the neighbouring districts of the mainland of 

 Ireland were made by Dr. E. Penard, the work being con- 

 tinued later by Mr. G. H. Wailes. The present report 

 has been drawn up under the joint authorship of these two 

 investigators. The total number of species and varieties 

 recorded is 140, of which Cryptodifflugia eboracensts, 

 Euglypha cirrata, E. rotunda, and E. armata, as well as 

 several varieties, are new to science. Seven other species 

 are new to the British Islands.— D. J. Scourfield : Fresh- 

 water entomostraca. In a preliminary report Mr. Scour- 

 field states that 41 species of Cladocera, 23 species of 

 Copepoda, and 13 species of Ostracoda have been observed 

 on Clare Island and the neighbouring parts of the main- 

 land. No new species have as yet been definitely identified, 

 but a couple mav eventually prove to be new to science. 

 The great majority of the species recorded are common 

 tvpes in the British Islands ; only a few are to be con- 



