August 2, 1900] 



NATURE 



335 



is thus doing a service to the nation, as well as extending interest 

 in natural knowledge. Dr. P. Bedson, professor of chemistry at 

 the Durham College of Science, has, we are glad to see, recently 

 shown the Economic Society of Newcastle-on-Tyne some of the 

 lessons taught by the growth of science and industry in Germany 

 during the present century. A reasonable and organised system 

 of education, and schools in which students receive a thorough 

 grounding in the principles of science, and afterwards contribute 

 something to the advancement of knowledge, are the chief factors 

 in Germany's industrial progress. Referring to the system of 

 examinations which still dominates so much of our educational 

 work, and finds its highest development in connection with 

 university teaching. Prof. Bedson points out that it partakes of 

 the character of the training of a stud of racers. He adds :— 

 " Possibly the instinct of sport, so characteristic of the English 

 people, it is which commends the system of competitive examina- 

 tion. Too much is made of what should be regarded as a minor 

 duty of the University, viz. the testing and marking of its 

 students, and too little of the higher function, the training of 

 students under first-rate teaching, with the object that those so 

 trained should help forward the advancement of knowledge." It 

 is satisfactory to know that the movement in favour of rational 

 teaching in elementary schools, and regard for research in insti- 

 tutions of university rank, is gradually affecting scientific education 

 in this country. 



SCIENTIFIC SERIALS. 



Sy /nous's Monthly Meteorological Magazine, July. — This 

 number contains the completion of two interesting papers, by 

 Mr. E. D. Archibald, on Indian famine-causing droughts, and 

 their prevision. The principal facts are summarised as follows : 



(1) Extensive droughts occur in the dry area of Southern India 

 at intervals of nine to twelve years, and usually, hut not regularly, 

 about a year before the sun-spot minimum. When the condi- 

 tions are sufficiently acute, famine occurs in the following year. 



(2) A severe drought in the peninsular of Southern India is 

 followed by a severe drought and ensuing famine in Northern 

 India in about five cases out of seven. (3) Summer droughts 

 tend to occur in Northern India in years of maximum sun-spot, 

 connected in some way with the abnormal high pressure over 

 Western Asia which prevails at such epochs. There is thus a 

 double periodicity of droughts and famine in North India, and a 

 single periodicity in South India in the sun-spot cycle, though 

 the relation between the phenomena is too spasmodic and 

 irregular to be utilised as a trustworthy factor for prevision. 



Amialen der Physik, No. 6. —Interruption spark in the alter- 

 nating circuit with metallic electrodes, by L. Kallir. The 

 author shows that the impossibility of producing an alternate- 

 current arc between metallic electrodes is due to the fact that 

 the spark is confined to one semi-period of the current. Or if 

 it extends over several periods, it is intermittent, and only 

 appears at every alternate semi-period.— Thermoelectric force 

 of some metallic oxides and sulphides, by A. Abt. Pyrolusite, 

 pyrrhotite, pyrites, and chalcopyrite were used in conjunction 

 with various metals or with each other. A pyrites-chalcopyrite 

 couple gave an E.M.F. lO'S times as high as an antimony- 

 bismuth couple under the same conditions.— Anomalous electro- 

 magnetic rotatory dispersion, by A. Schmauss. Measurements 

 of the Faraday effect for various wave-lengths in fuchsine solu- 

 tions and in didymium glass justify the general conclusion that 

 optical anomaly in dispersion is invariably associated with a 

 corresponding electromagnetic anomaly. In strongly absorbing 

 media the anomaly extends for a considerable distance on both 

 sides of the absorption band, and it increases with the con- 

 centration and with the narrowness and sharpness of the ab- 

 sorption band.— Point discharges, by E. Warburg. In care- 

 fully purified nitrogen, the current intensity obtained from the 

 discharge of a fine point charged to - 3310 volts is 200 times as 

 great as from a point charged to -f5i8o volts. A slight ad- 

 mixture of oxygen reduces the proportion to 4 : i.— Band 

 spectrum of aluminium, by G. A. Hemsalech. The author 

 quotes some experiments which go to show that the band 

 spectrum of aluminmm is due, not to the oxide, but to the 

 metal itself.— Behaviour of radium at low temperatures, by O. 

 Behrendsen. Cooling a radium preparation down to the 

 temperature of liquid air reduces its activity by 50 per cent. 

 Restoration to the ordinary temperature produces a considerable 

 but transient increase of activity.— Production of kathode rays 

 by ultra-violet light, by P. Lenard. The discharge of electrified 

 NO. 1605, VOL, 



62] 



bodies by ultra-violet light is due to their emitting kathode rays 

 when the ultra-violet light impinges upon them. The author 

 exhausted a vacuum tube until it no longer allowed any dis- 

 charge to pass. He then exposed the kathode to ultra-violet 

 rays from a zinc spark gap. The discharge set in again 

 immediately, but no discharge could be ol)tained by similarly 

 illuminating the anode. The rays which produce the discharge 

 across the absolute vacuum can be deflected by a m^ignet, and 

 their velocity is about one-thirtieth of the velocity of light. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, February 8. — "On Electric Touch and the 

 Molecular Changes produced in Matter by Electric Waves." By 

 Jagadis Chunder Bose, M.A., D. Sc, Professor of Physical 

 Science, Presidency College, Calcutta. Communicated by Lord 

 Rayleigh, F.R.S. 



It is claimed that the experiments described in the paper 

 show : — 



(i) That ether waves produce molecular changes in matter. 



(2) That the molecular or allotropic changes are attended with 

 changes of electric conductivity, and this explains the action 

 of the so-called coherers. 



(3) That there are two classes of substances, positive and 

 negative, which exhibit opposite variations of conductivity under 

 tVie action of radiation. 



(4) That the production of a particular allotropic modification 

 depends on the intensity and duration of incident electric 

 radiation, 



(5) That the continuous action of radiation produces oscillatory 

 changes in the molecular structure. 



(6) That these periodic changes are evidenced by the corre- 

 sponding electric reversals. 



(7) That the " fatigue " is due to the presence of the " radia- 

 tion product," or strained B variety. 



(8) That by means of mechanical disturbance or heat, the 

 strained product can be transformed into the normal form, and 

 the sensitiveness may thereby be restored. 



June 21. — "An Experimental Investigation into the Flow of 

 Marble." By Frank D. Adams, M.Sc, Ph.D., Professor of 

 Geology in McGill University, Montreal, and JohnT. Nicolson, 

 D.Sc, M.Inst. C.E., Head of the Engineering Department, 

 Municipal Technical School, Manchester. Communicated by 

 Prof. H. L. Callendar, F.R.S. 

 The following is a summary of the results arrived at : — 

 (i) By submitting limestone or marble to differential pressures 

 exceeding the elastic limit of the rock and under the conditions 

 described in this paper, permanent deformation can be pro- 

 duced. 



(2) This deformation, when carried out at ordinary tempera- 

 tures, is due in part to a cataclastic structure and in part to 

 twinning and gliding movements in the individual crystals com- 

 prising the rock. 



(3) Both of these structures are seen in contorted limestones 

 and marbles in nature. 



(4) When the deformation is carried out at 300° C, or better 

 at 400° C, the cataclastic structure is not developed, and the 

 whole movement is due to changes in the shape of the com- 

 ponent calcite crystals by twinning and gliding, 



(5) This latter movement is identical with that produced in 

 metals by squeezing or hammering, a movement which in 

 metals, as a general rule, as in marble, is facilitated by increase 

 of temperature. 



(6) There is therefore a flow of marble just as there is a flow 

 of metals, under suitable conditions of pressure. 



(7) The movement is also identical with that seen in glacial 

 ice, although in the latter case the movement may not be 

 entirely of this character. 



(8) In these experiments the presence of water was not 

 observed to exert any influence. 



(9) It is believed, from the results of other experiments now 

 being carried out but not yet completed, that similar movements 

 can, to a certain extent at least, be induced in granite and other 

 harder crystalline rocks. 



" On the Effects of Changes of Temperature on the 

 Elasticities and Internal Viscosity of Metal Wires." By 

 Andrew Gray, LL.D., F.R.S., Professor of Natural Philosophy 

 in the University of Glasgow, and Vincent J. Blyth, M.A., and 



