^34 



NATURE 



[April 13, 191 



origin uf the British Trius. Phenomena observed in the 

 Eastern Desert of Egypt, bordering the (julf of Suez, are 



• described. The origin of the mounds of igneous debris 

 which flank the coastal hilt-rangi-s is discussed. The 



• distances to which fragments of igneous r<K-k derived from 

 these hills have travelled in Egypt are shown. The shore- 

 sands are dealt with, and their origin ascribed to the 

 breaking down of local rocks. In the marly beds con- 

 •nected with the shor<"-de{)osits, tiny dolomite-rhombs, 

 similar to those found by Ur. Cullis in the Keuper Marls, 

 are present. Some effects of wind-blown sand are 



-detailed. The alteration of the calcium carbonate in 

 recent shell-beds to gypsum is noted, and its significance 

 with regard to the origin of gypsum-beds is pointed out. 

 The characters of the massive older gypsum- and rock- 

 salt deposits arc described, together with the distribution 



• and lithological changes in the beds when traced across 

 the area. The origin of the gypsum series is connected 

 with inland salt-lake conditions, and the evidence suggests 

 that these conditions were contemporaneous with the 

 Oligocene continental period in Egypt, and with the 

 formation of the beds of the F"ayilm in the Western Desert. 

 — H. Bolton : Eaunal horizons in the Bristol coalfield. 

 The existence of fauna! horizons at the collieries in the 

 Bristol and Gloucestershire area, and in the Radstock 

 area, has been determined. A measured section has been 

 examined in detail, and four faunal horizons discovered. 

 In every case the fauna was marine in character, and the 

 series are all characterised by a fauna agreeing with the 

 typical fauna of the Lower Coal Measures of the coal- 

 fields of the Midlands, and of Lancashire and Yorkshire. 

 ■Species of Carbonicola are rare, while the cephalopod and 

 fish fauna is poor. The second series of the Upper Coal 

 Measures has yielded Lingula mytiloides, several species 



•of ostracods, four species of Anthracomya, and scales of 

 Strepsodus satiroides. Coelacanthus elegans has been 

 tound in the first series. In the Bristol coalfield the 

 marine fauna undergoes no marked change in its upward 

 range. Insect-wings referred to the genus Genentomum 

 have been found at one horizon, while the rare phyllopod, 

 Leaia leidyii, var. salicriana, hitherto only known from 

 the Lower Carboniferous of Fifeshire, was found in abund- 

 ance. The total number of species now recorded from the 

 Bristol coalfield amounts to seventy-four. 



Mineralogical Society, March 2!.— Prof. W. T. Lewis, 

 F.R.S., president, in the chair. — Prof. W. J. Lewis: Mr. 

 Solly's observation of wiltshireite in 1903. Wiltshireite is 

 identical with the mineral which Mr. Solly exhibited and 

 described before the society, November 17, 1903, and subse- 

 <juently named rathite a, but of which no complete descrip- 

 tion has yet been published. — R. H. Solly : Two new 

 minerals from the Binnenthal, Switzerland. Both arc prob- 

 ably sulpharsenites of lead, being lead-grey in colour and 

 giving a chocolate-coloured streak ; one, which is rhombo- 

 hodral-diplohedral, and has an angle iii : 100 = 38° 18', is 

 probably Lsomorphous with trechmannite, while the other 

 may be orthorhombic, the angle 100: no being ^8° 18', but 

 no measurable end faces were observed. — J. B. Scrlvenor : 

 "Notes on cassiterite in the Malay Peninsula. Cassiterite 

 from a mine at Gopeng- contains ilmenite and magnetite, 

 and is attracted by the magnet; it also occurs mixed with 

 tourmaline pseudomorphic after an hexagonal mineral, 

 probably quartz. — Arthur Russell : Notes on the occurrence 

 ■of dundasite in Derbyshire and co. Galway, and of 

 bertrandite in Cornwall. Dundasite was discovered at Mill 

 Close mine, Wensley, Derbyshire, as snow-white spheres 

 tissociated with greenockite, fiuor, cerussite, calamine, &c., 

 iind at Clements lead iiiine, Carrowgarriflf, near Maam, 

 CO. Galway, associated with allophane and cerussite, and 

 "bertrandite was found in platy crystals on old specimens of 

 blende from Wheal Vor, Breag^e, Cornwall, and as 

 trillings, measuring up to 4 mm. in length, on a specimen 

 from Wheal Metal, Breage, Cornwall, which had been 

 presented as albite to the British Museum in 1870 ; in the 

 latter case the crystals were similar to those from Pisek, 

 Bohemia, described by C. Vrba. — Dr. J. Drugrman : 

 ■Quartz-twinning. The possible varieties of twinning of 

 quartz were discussed, with special reference to the rhombo- 

 hedron type, a specimen of which was exhibited. — T. V. 

 Barker: CrystalloRraphic notes. Two new forms found 

 ■on crystals of inosite confirm the hypohexagonal type of 



NO. 2163, VOL. 86] 



symmetry suggested by Fedorow. The rhombohf; 



modification ol potassium nitrate, unlike «,'»'«•'•" ■• •• 



ducji not arrange itself regularly when <1 



cleavage piece oJ calcite ; the crystals arc ver. 



rapidly pass into the ordinary orthorhombic iurtit. A 



parallel growth of calcium chromate on the isomorphou* 



mineral gypsum was obtained. New forms 1; 



observed on urea nitrate which enabled the axial 



for the first time to be calculated; the crystals hu... ■•n^v 



birefringence, and, when grown in a drop, are nearly 



always twinned. 



Physical Society, March 24.— Prof. H. L. Calleodar 

 E.k.S., president, in the chair. — Dr. H. F. Maworth 

 (1) A sensitive thermo-regulator ; (2) experiment 

 measurement of electrolytic resistance using aL..;.„; ., 

 currents. The " thermo-regulator " consists of a lolu<.:r 

 thermometer with mercury platinum contacts in •! 

 capillary tube; these contacts operate, through a Siem<-:i<> 

 telegraph relay, an electromagnetic switch, which cuts -.u 

 or out the heating circuit. On account of the \ 

 current required to operate the relay, a fine cap: 



be used, so ensuring a high magnification v. 



thermal capacity. E.\|>eriments were also shown ill.--^- 

 trating the ease with which a bridge containing an elecir'- 

 lytic ceil could be balanced by placing a variable s- !l- 

 induction in series with the cell and adjusting it and ti.*- 

 resistance of the bridge simultaneously, as in Wieir> 

 experiments, except that a vibration galvanometer w. lo- 

 used in place of the optical telephone originally —•••>'! 

 by Wien. The author's deduction from his e\ 

 was that the resistance of an electrolyte varies 

 frequency of the alternating E.M.F. applied. — Pro.. 

 G. W. O. Ho«ve : Oscillatory currents in coupled circuit-. 

 A demonstration was given by means of a double projec- 

 tion oscillograph of the currents in coupled oscillatory 

 circuits. Each circuit consisted of a condenser, an air- 

 ore choking coil, and a strip of the oscillograph. The 

 condenser in the primary circuit was charged and dis- 

 charged by means of a commutator on the spindle of the 

 oscillograph motor. The two circuits may be taken to 

 represent the condenser circuit and the aerial of a wire- 

 less telegraph sending apparatus, the frequency being tvio 

 or three hundred instead of a million. The currents in 

 the two circuits can be studied, and every change due to 

 a variation in the damping of either circuit or in the 

 coupling between the two circuits can be followed. This 

 was illustrated by a series of typical photographic records. 

 A third oscillatory circuit may be taken to represent a 

 wave-meter, and used to plot resonance curves, from which 

 the damping can be calculated, as is commonly done in 

 radio-telegraphic work. Here, however, we have the 

 great advantage of knowing the damping accurately, and 

 thus being able to check the resonance curve results under 

 various conditions. By altering the connections, the con- 

 ditions of the quenched spark sending apparatus, as used 

 by Max Wien, Lepel, &c., was represented. Here the 

 primary circuit is opened at the first moment that all the 

 energy has been transferred to the secondary circuit, and 

 no further beats or spark-gap losses occur. Results were 

 given showing that the oscillograph can be used to find 

 the losses in condensers at various frequencies by dis- 

 charging the condensers through inductances of knowr 

 resistance. — Prof. G. W. O. Howe : Some radio-tele- 

 graphic apparatus in use at the City and Guilds College. 

 The wireless telegraphic receiving apparatus was showll 

 connected up to the aerial, which is 260 feet high. A trans- 

 former specially designed for experimental work at long 

 wave-lengths w-as shown. By means of a Brown telephone 

 relay and special trumpets fitted to the telephone receiver, 

 the time signals and messages sent out from Norddeich 

 and from the Eiffel Tower can be plainly heard anywhere 

 in the lecture theatre. The various types of receiving 

 apparatus ^n use at the college were shown. 



Zoologrical Society. April 4. — Dr. Henry Woodward 

 F.R.S., vice-president, in the chair. — Dr. H. B. Faitthatw 

 and Dr. Annie Porter : Diseased bees and combs infected 

 with a minute pathogenic protozoal parasite, apparently 

 the same as Nosenta apis found by Zander and Etoflein in 

 diseased bees in Bavaria. Microscopic preparations and 

 drawings of the parasite. A', apis, were also shown, as 



