April 27, 1899] 



NATURE 



621 



vited by the Education Sub-Committee of the Royal Commis- 

 sion for the Paris Exhibition of 1900 to co-operate in the work 

 of securing for the exhibition an adequate and comprehensive 

 representation of all grades of educational effort, public and 

 private, in the United Kingdom, and Sir Owen Roberts has 

 been appointed by the Executive Committee to attend the 

 conferences convened by the Chairman, Sir George Kekewich, 

 K.C.B., to consider the arrangements for the educational 

 section. 



SCIENTIFIC SERIALS. 



American Journal of Science, April. — Glacial Lakes Newberry, 

 Warren, and Dana in Central New York, by H. L. Fairchild. 

 The ice sheet of the last glacial epoch covered all the area of 

 the Great Lakes. When the receding front of the glacier had 

 passed to northward of the southern boundary of the Laurentian 

 basin, the glacial and meteoric waters were impounded between 

 the ice front and the north-sloping land surface. These glacial 

 lakes had their outlets southward across the divide, and they 

 expanded northward as the barrier of ice receded. The author 

 describes the succession of events in the life and extinction of 

 the later and broader glacial waters in the critical district of 

 the Finger Lakes. — Rapid method for the determination of the 

 amount of soluble mineral matter in a soil, by T. H. Means. 

 This method is an electrical one. The sample is treated with 

 distilled water and the specific resistance of the solution is deter- 

 mined. Two men can thus examine from sixty to one hundred 

 samples of soil in a day, and salt maps of irrigated and other 

 districts may be rapidly constructed. — New type of telescope 

 objective specially adapted for spectroscopic use, by C. S. 

 Hastings. The author has constructed an objective consisting 

 of a quadruple combination of silicate flint, borosilicate flint, 

 silicate crown, and barium crown which is absolutely colour- 

 free, and equally adapted to photographic and to eye observ- 

 ations. From the lines A to K, the focal plane for all rays is 

 rigidly the same. There are only two free surfaces, the four 

 lenses being cemented together. — On the phenocrysts of 

 intrusive igneous rocks, by L. V. Pirsson. Not all phenocrysts 

 are intratelluric in the sense that they have been formed at 

 much greater depths than they now occur in. On the contrary, 

 in many cases they have been formed in place, and are of contem- 

 poraneous origin with the other constituents of the rocks. — The 

 occurrence, origin, and chemical composition of chromite, by 

 J. H. Pratt. The author has been led to adopt the theory that 

 the chromite occurring in the peridotite rocks of North Carolina 

 was formed at the .same time as the peridotite, i.e. was held in 

 solution by the molten nia.ss of the peridotite and crystallised 

 out among the first minerals as the mass began to cool. — Two 

 species of Saurocephalus, by O. P. Hay. One of the species 

 described, S. lanciformis, is little known. The other species 

 is new. It has a slenderer head and a larger mouth than 

 6'. dentatus. The author names it .S. pamphagus. 



Correction. — The abstract of G. P. Starkweather's paper. 

 Am. J. Sc. for February, should read : The writer adduces 

 evidence from Regnault's own experiments to show that his 

 calorimeter temperatures were reduced to the air thermometer, 

 a fact questioned by Bosscha and others. 



Symonss Monthly Meteorological Magazine, April. — Winter 

 minima on British mountain tops. In 1867, the late Mr. H. B. 

 Biden placed a minimum thermometer on the Glyder fach, 

 about four miles E. N.E. of Snowdon, at an altitude of 

 3262 feet. The thermometer was placed beneath a protecting 

 slab of feldspar porphyry, and left to its fate, being read each 

 spring, and then reset. Mr. W. Piffe Brown has discussed the 

 temperatutes in the Climbers' Club journal for February last. 

 The average for the years 1884-96 except 1894-95, w'hen the 

 record was lost) was 14 7, the absolute minimum being 

 8°, in the winter of 1893-94. The accumulation of snow may 

 account for the readings not being lower, but it is improbable 

 that there was always snow there at times of severe cold. At 

 Ben Nevis, the average of the minima for the same period is 

 7°'5, the absolute minimum being o""/ in January 1S94. A 

 very contradictory record was obtained by the late Dr. J. F. 

 Miller at Scaw Fell, where the wonderful temperature of -31° 

 was recorded for January and February 1850. — Negretti and 

 Zambra's self-recording rain gauge. Mr. Symons states that 

 this is a very simple and efficient instrument ; the rain collected 



NO. 1539, VOL. 59] 



by the receiver falls into the upper half of the vibrating bucket 

 (designed by Sir Christopher Wren). When o'l inch of rain 

 has fallen, the bucket tips over and causes a wheel to advance 

 one tooth. Attached to the wheel is a helix on which rests the 

 lever carrying the pen which registers each turnover of the 

 bucket. As the clock (the useful invention of MM. Richard freres) 

 turns the paper about 'ooi inch per minute, a very clear curve 

 is produced. The approval of the instrument by Mr. Symons 

 is a guarantee of its usefulness, and the cost is much below 

 some other recording gauges. 



The journal of the Royal Microscopical Society for April 

 contains the President's annual address, which is chiefly 

 devoted to the subject of dispersion ; the description of a 

 microscope with new focussing mechanism, by Mr. Keith 

 Lucas ; and notes on colour-illumination, with special reference 

 to the choice of suitable colours, by Mr. Julius Rheinberg. 

 Among the notes on microscopy is a contribution to the Presi- 

 dent's interesting article on the evolution of the microscope, 

 and a description of Powell's iron microscope made in 1S38-40. 

 In the same number is a table of the conversion of British and 

 metric measures, computed by Mr. E. M. Nelson from the new 

 coefficient obtained by order of the Board of Trade in 1S96. 



Wiedemann^ s Annalen der Physik und Cheinie, No. 3. — Be- 

 haviour of unpolarisable electrodes towards alternate currents, 

 by E. Warburg. If polarisation is altogether due to the solution 

 of the electrode metal in the liquid .and its attendant changes 

 of concentration, the " capacity of polarisation" must be in- 

 versely proportional to the square root of the frequency. This 

 applies to the case of silver electrodes in silver nitrate solution, 

 and, to a certain extent, to platinised ]ilatinum electrodes in 

 saturated NaCl solution. — Methods of studying slow electric 

 oscillations, by W. Konig. The author describes several new 

 methods of recording and studying electric oscillations of a fre- 

 quency comparable with that of ordinary sound-waves. One of 

 these consists in discharging them through a rod provided with 

 a short piece of straw at the end on to a metallic plate covered 

 with asphalt varnish. The sparks produce on the plate some- 

 thing resembling Lichtenberg's figures. The plate is attached 

 to a pendulum, and is drawn across the point. On sprinkling 

 the plate with a mixture of sulphur and red lead a series of red 

 and yellow patches appears, which in connection with the 

 known speed of the pendulum gives the frequency of the sparks. 

 The straw may also be attached to the vibrating prong of a 

 tuning-fork, and so a more direct measurement obtained. The 

 straw is necessary to reduce the intensity of the spark, so as to 

 obtain a sharp line. — A new method of exhibiting electric wire 

 waves, by W. D. Coolidge. The author obtains a glow of the 

 wires of a Lecher wire system at the ventral segments of the 

 stationary waves in the open air by using a Blondlot exciter 

 worked with an induction coil and Tesla transformer, and re- 

 ducing the thickness of the wire to o'l mm. — Alternate-current 

 energy consumed in vacuum tubes, by 11. Ebert. \ ery high 

 frequencies were employed, such as 22,000 oscillations per 

 minute. It was found that at a certain high exhaustion the 

 consumption of energy for a given luminous effect attained a 

 minimum. The pressure at which this takes place is inversely 

 proportional to the mean free path of the gaseous molecules. — 

 Absolute determination of thermal radiation by means of the 

 electric compensating pyrheliometer, by K. Angstrom. Of two 

 equal blackened strips of metal, one is exposed to the radiation 

 while the other is brought to the same temperature by means 

 of an electric current. The latter furni.shes a measure of the 

 radiation. — Measurement of flame temperatures by means of 

 thermocouples, by F. Berkenbu.sch. Two new methods de- 

 vised by Nernst are tested. — Pressure of saturated water vapour 

 below 0°, by M. Thiesen. The author calculates the vapour 

 pressures over ice and over water respectively down to - 80°. 



SOCIETIES AND ACADEMIES. 

 London. 

 Physical Society, April 21.— Mr. T. H. Blakesley, Vice- 

 President, in the chair. — A mathematical paper on the effect of 

 a solid conducting sphere in a variable magnetic field on the 

 magnetic induction at a point outside, was read by Mr. C. S. 

 Whitehead. It is an investigation of the magnetic induction at 

 a point outside a solid conducting sphere when magnetic dis- 



