ASSOCIATIONS FOR THE ADVANCEMENT OF SCIENCE. 



nich, it was resolved that it was " necessary that 

 the instruments employed for absolute measure- 

 ments at the different observatories should be 

 compared with each other and the results pub- 

 lished." Notwithstanding the urgency of this 

 matter, nothing had been done. In recent years 

 much activity had been displayed in the conduct 

 of local magnetic surveys, and the great desira- 

 bility of collecting the results obtained was 

 pointed out. An official international compari- 

 son of the magnetic standards in different coun- 

 tries should be instituted, and for this purpose it 

 would be necessary to begin by comparing the 

 standard magnetic instruments in use in the 

 different observatories. Already one step in this 

 direction has been taken by the Royal Society, 

 which will publish the records obtained in Fal- 

 mouth side by side with those obtained in Kew. 

 The cause of the variations on the magnetic 

 condition of the earth has entered a new stage. 

 It has long been recognized that the earth is not 

 a simple magnet, but that there are in each hemi- 

 sphere one pole or point at which the dip of the 

 needle is vertical and two foci of maximum in- 

 tensity. The conclusion is now tending to a be- 

 lief that one or both foci in each hemisphere is 

 in motion, and that to this motion, however 

 caused, the secular change in the values of the 

 magnetic elements is due. New facts lead us to 

 look upon the earth not as magnetically inert, 

 but as itself at the equator as well as at the 

 pole producing or profoundly modifying the 

 influences which give rise to secular change. 

 Experiences tell the same tale.. The earth seems 

 alive with magnetic forces, be they due to elec- 

 tric currents or to variations in the state of 

 magnetized matter. Two causes of regional and 

 local disturbances have been suggested, viz., 

 earth currents and the presence of magnetic 

 rocks. After discussing these theories the fol- 

 lowing subjects for future investigation were 

 considered : First, as to the nature of the ma- 

 terial causing local magnetic disturbances, 

 whether virgin iron or pure magnetite, or merely 

 a magnetic rock ; and, second, as to the perma- 

 nent magnetization of magnetic rocks. 



Among the important papers presented before 

 this section were : 



" Preliminary Experiments to find if Subtraction 

 of Water from Air causes its Electrification," hv Lord 

 Kelvin and Magnus Maclean ; " Comparison of Ley- 

 den Jar Discharges through Different Branches of a 

 Divided Channel," by Lord Kelvin and Alexander 

 Gait; "Photo-electric Leakage," by Oliver Lodge. 

 On Friday, Aug. 10, a joint meeting was held of this 

 section with the section on mechanics for the pur- 

 pose of listening to a discussion " On Integrators, Har- 

 monic Analyzers, and Integraphs, and their Applica- 

 tion to Physical and Engineering Problems,'' by 

 Prof. Olaus Henrici, followed by papers on ''The Be- 

 havior of a Rotating Cylinder m a Steady Current," 

 by Arnulph Mallock ; " The Resistance experienced 

 by Solids moving through Fluids," by Lord Kelvin. 

 Then came a paper describing " Experiments in the 

 Construction of a Flying Machine," by Hiram Maxim, 

 which was discussed by" Lord Rayleigh, Prof. Samuel 

 P. Langley, Lord Kelvin, and Prof. O.s!>onie Reynolds; 

 Other papers \vere " A New Analytical Representation 

 of Terrestrial Magnetism," by Adolph Schmidt; "An 

 Experiment showing the Boiling of Water in an 

 Open Tube," by Osborne Reynolds; "Researches on 

 the Infra-red Spectrum," by Samuel I'. Laiiirley, of 

 Washington, I). C. ; " Suggested Explanation of oeo- 



ular Variations of Terrestrial Magnetism " and " Con- 

 struction of Delicate Galvanometer," by Arthur 

 Schuster; "Minimum Current audible iri the Tele- 

 phone," " An Attempt at a Quantitative Theory of 

 the. Telephone," and "Amplitude of Sonorous Waves 

 which are but just audible," by Lord Rayleigh ; "On 

 the Production of Beats and Beat Tones from Notes 

 so high as to be inaudible " and " The Variation of 

 the Modulus of Elasticity with Temperature," by Al- 

 fred M. Mayer, of Hoboken, N. J. ; "An Instrument 

 for measuring Small Strains," by J. A. Ewing; 

 " Volume Changes accompanying Magnetization m 

 Nickel Tubes," by C. G. Knott; "Hysteresis of Iron 

 and Steel in rotating Magnetic Fields," by F. G. 

 Baily ; " Mirrors of Magnetism," by Silvanus P. 

 Thompson. 



On Aug. 14 a joint session was held with the 

 section on physiology, to discuss theories of vision 

 resulting from certain experiments to illustrate 

 Clerk Maxwell's theory of light presented by 

 Oliver Lodge : 



" Determination of the International Ohm in Abso- 

 lute Measure " and " An Electrical Standard of Low 

 Resistance," by J. Vivianus Jones ; " The Comparison 

 with the British Association Units of some Coils of 

 Low Resistance," by R. T. Glazebrook ; " The Specific 

 Resistances of Silver and Copper," by T. C. Fitzpat- 

 rick- and "Displacement of the Rotational Axis of 

 the Earth," by W. Forster. There were presented 

 also " Report on the Present State of our Knowledge 

 on Thermodynamics," by G. H. Bryan; "Report of 

 the Committee on Earth Tremors," by J. G. Symons ; 

 " Report of the Committee on Meteorological Pho- 

 tography," by G. W. Clayden; "Report of the Com- 

 mittee on Underground Temperature ; " " Report of 

 the Committee on Solar Radiation ;" and the "Report 

 of the Committee on Electric Standards." 



B. Chemical Science. This section was pre- 

 sided over by Prof. Harold B. Dixon, of Owens 

 College, Manchester, who addressed the members 

 concerning " Our Oxford School of Chemists." 

 As the chemists were gathered in Oxford, it 

 seemed appropriate to consider what this " school 

 of chemists had accomplished, and wherein it 

 failed ; what led to the sudden growth, and what 

 led to the decline of chemical investigation here, 

 and what lessons for modern Oxford may be read 

 in the history of that rise and fall." Robert Boyle 

 was born in 1624, and went to Oxford in 1654. 

 His writings contained the record of numerous 

 important chemical observations, notably the 

 synthesis of niter and the preparation of nitric 

 acid by the distillation of niter with oil of vitriol. 

 He discovered several delicate tests still in use, as 

 that of solution of ammonia for copper, silver 

 nitrate for chlorides, and gallic acid for iron. 

 Like Van Helmont, Boyle recognized differences 

 in gases, but did not distinguish them as being 

 different in kind from air. He prepared hydrogen 

 by the action of hydrochloric and sulphuric acids 

 on iron, but his concern was to show that the new 

 gas was compressible, and was dilatable by heat. 

 His observations contained the first undoubted 

 description of hydrogen, and the first method de- 

 vised for collecting and examining freshly pre- 

 pared gases. The genius of Robert Hooke was 

 in sharp contrast with that of Boyle. Quick, 

 restless, imaginative, he sprang from discovery 

 to discovery. We could hardly name a discovery 

 of this age which Hooke had not in part antici- 

 pated and claimed as his own. In 1665. Hooke 

 published a description of flame and the phe- 

 nomena of combustion thlit perhaps has never 

 been surpassed. Mayow went further, and dis- 



