SCIENCE- G OSS IP. 



iS5 



CONDUCTED BY JAMES <,>rH'K. 



Physics at the British Association.— At tin- 

 meeting of the British Association at Bradford, 

 just ended. Seel inn A (Physics) was characterised 

 by some brilliant papers, both theoretical and 

 practical. The address of the president of 

 Section A, Dr. J. Larmor, F.R.S., opened the 

 proceedings on Thursday, September 6. It was an 

 excellent resume of the work of some of the fore- 

 most physicists and mathematicians of the present 

 century, and also included a lucid explanation of 

 recent researches in the realm of atoms and ionic 

 charges. Among the papers which followed that 

 of Dr. Larmor was one by Messrs. A. Dufton and 

 W. M. Gardner on " The Production of an Artificial 

 Light of the same character as Sunlight," an in- 

 teresting exhibition of contrast-colours accompany- 

 ing the reading. It was pointed out by the authors 

 what a common experience it is that many colours 

 alter in appearance when seen by artificial light, 

 and how difficult it is for colour-workers to pro- 

 duce their work satisfactorily when working with 

 anything else but daylight. They use at present 

 the light from an electric arc as being the best 

 approach, but it is not efficient. The peculiar 

 character of daylight is clue essentially to the 

 selective absorption exercised by the atmosphere, 

 and the success which the authors of the paper 

 have attained is due partly to their having 

 taken advantage of this fact. They have filtered 

 the light from an arc lamp, by means of trans- 

 parent solutions of coloured glasses, to as nearly 

 as possible the same extent that does the atmo- 

 sphere. Friday. September 7, was taken up entirely 

 with mathematical physics papers, although Dr. 

 Larmor, in his communication on " The Dynamical 

 Statistics of Gas Theory, illustrated by Meteor 

 Swarms and Optical Rays," led up to the mathe- 

 matical considerations by some very clear graphical 

 illustrations. Saturday was a practical day, in 

 that papers were read upon the practical applica- 

 tions of physics. After the reports of one or two 

 Committees upon physical matters had been read, 

 Sir William Preece gave an interesting- account of 

 his work on " Wireless Telephony." The first 

 experiments were made in 1S!>4 across Loch Ness. 

 Preece's electromagnetic system for wireless tele- 

 graphy was set up, and trials were made to compare 

 telephonic signals with the ordinary telegraphic 

 ones, to ascertain whether speech could he main- 

 tained under the same conditions as for Morse sig- 

 nalling. The results were satisfactory, speech being 

 exchanged across the loch at an average distance 

 of 1^ mile between the two parallel wires. Further 

 experiments in 1899 showed that the maximum 

 effects were produced when the parallel wires were 

 terminated by earth-plates in the sea, the conduc- 

 tive effect through the water greatly increasing 

 the efficiency of the apparatus. Ordinary telephonic 

 transmitters and receivers were used. These sucr 

 cessful results, as might have been expected, ha\e 



been quickly followed up by practical and 

 applications. It being necessary to establish 



con inications between th« islands known as 



the Skerries and the Anglesey mainland, this 

 system of wire].— telephony was determined 

 upon, as the bottom of the channel between 

 the two [joints is too rough and the currents 

 too violent for a cable to be laid. A wire 750 

 yards in length was therefore erected along the 

 Skerries, and on the mainland one of 3^ miles from 

 a point opposite the Skerries to Cemlyn. Bach 

 line terminates by an earth-plate in the sea. The 

 average distance between the parallel portions of 

 the t wo wires is 2*8 miles. Telephonic communica- 

 tion is easily maintained, and the service is proving 

 a good one. Mr. C. E. S. Phillip- read a paper on 

 "The Apparent Emission of Cathode Bays from an 

 Electrode at Zero Potential."' and showed that the 

 green patches which often appear on the surface 

 of the walls of a Rontgen-ray tube, while a dis- 

 charge is passing, are due to irregularities on t he- 

 surface of the cathode, as they could be made to 

 alter their position when a movable cathode was 

 employed; and, moreover, that there was strong 

 evidence for regarding an emission of gas in jets 

 as taking place from the electrodes. Probably 

 one of the most important and exciting papers 

 read before Section A was that by Professor J. 

 Chunder Bose, of Calcutta, on "The Similarity of 

 the Effect of Electrical Stimulus on Inorganic and 

 Living Substances." Professor Bose has, indeed, 

 made important strides into the realm of the 

 propagation of electrical waves, and has gone very 

 far towards completely bridging the experimental 

 gap between optical phenomena and Hertzian 

 wave phenomena. He has paid special and un- 

 tiring attention during the last few years to 

 the subject of the " coherer " principle, and 

 has now put forward theoretical suggestions 

 which, to say the least, are astonishing, not 

 only in the departments of physics and chemistry, 

 but also of biology. We are to think of an elec- 

 tric stimulus as of the nature of a stress, pro- 

 ducing in many forms, according to the subject 

 or substance acted upon, what ma) T be termed a 

 strain. Within limits the strain is proportional to 

 stress, but fatigue occurs when the stress is ex- 

 cessive. These actions are to be considered as 

 being upon the atomic, or perhaps sub-atomic. 

 scale. Prof. Bose instanced many physical and 

 physiological phenomena strengthening his views. 

 Indeed, the parallel between the behaviour of a 

 coherer in an electric circuit and the behaviour of 

 living tissue in its ordinary physiological functions 

 is very close ; so much so as to be suggestive of a 

 common explanation. The author indicates such 

 an explanation in this electric stress-strain hypo- 

 thesis, since he regards vital function- as 

 the manifestations of an electric stimulus in a 

 substance (tissue), acting molecularly or atomic- 

 ally in the same manner ;i- does a coherer. 

 lie, indeed, carries hi- hypothesis into the 

 domain of every form of differentiated living 

 tissue. On Tuesday, September 11th. a long dis- 

 cussion upon the far-reaching subject of •'Ion-" 

 was opened by Prof. Fitzgerald, who objects to 

 the term ■• ionization." This term, he thought. 

 should only he used to denote the | 

 charged atoms. The discussiOD was taken up by 

 manv prominent physicists and also by Prof. 

 H. E. Armstrong, who said that the chemist 

 regarded an atom a- a -acred structure. 



