556 



SCIENCE. 



[N. S. Vol. XI. No. 275. 



On the whole this erruption of 47r's is not a 

 very serious matter, and it is not likely that an 

 international congress will soon take steps to 

 rid us of it. 



On the other hand there are some points of 

 advantage in our present definitions of magnet 

 pole and electric charge. It is all very well to 

 talk of defining electric current, as the curl of 

 magnetic force and of magnetic current as the 

 curl of electric force, indeed it is very simple 

 to think in this way when one has once ab- 

 stracted his knowledge of electrical things suf- 

 ficiently to make the images of these things 

 meet — but how about the beginner ? 



Such things as force, temperature and elec- 

 tric current are measured by their effects. For 

 example force may be measured by its distor- 

 ting effects on elastic bodies or by its effect 

 in changing the state of motion of a body. 

 One of the most evident effects of a magnet 

 pole is its attraction for other poles and the 

 present writer knows of no simpler way to 

 establish a quantitative basis for the discussion 

 of magnetism than to agree at once to measure 

 a magnetic pole in terms of its attraction for 

 a unit pole, the unit pole being that pole which 

 repels an equal pole at unit distance with unit 

 force. Then the force of attraction of any two 



poles is i'' = — 75— ■ Now it leads eventually 

 a' 



to simpler equations to so define the unit pole 



that F = but the present writer, for one, 



4-d^ 



would have some hesitation in presenting the 

 matter to a class in this initially more compli- 

 cated way with no other excuse than that a 

 certain remote advantage will come of it. Per- 

 haps the present writer, who finds his greatest 

 trials in teaching, is unreasonably timid. 



The most valid objection, however, to the 

 present recasting of our systems of electrical 

 units^for we are at present burdened with two 

 systems, not including the entirely useless prac- 

 tical system — is that we have no assurance that 

 a new system would stand. For, in the first 

 place, a new electrical relation must be dis- 

 covered before we can settle upon one system 

 of units ; and in the second place we do not 

 know even whether electric current and curl of 

 magnetic field are identical or merely propor- 



tional, as has been pointed out by J. J. Thom- 

 son. 



W. S. F. 



SCIENTIFIC NOTES AND NEWS. 



On the occasion of the bi-centenary celebration 

 of the Academy of Sciences at Berlin, Lord 

 Kelvin and Professor Max Miiller were elected 

 foreign members. Professor Willard Gibbs, 

 Professor H. A. Rowland, and Professor Wil- 

 liam James were among those elected Corres- 

 ponding Members. 



The marble statue of Huxley, which the Mem- 

 orial Committee has given to the Natural His- 

 tory Museum at South Kensington, will be un- 

 veiled on April 28th. It is expected that Sir 

 Joseph Hooker will makejan address on Huxley, 

 and that the statue will be received by the 

 Prince of Wales on behalf of the trustees of the 

 British Museum. 



President Gilbert of the American Associ- 

 ation for the Advancement of Science has 

 authorized a meeting of the Council at the 

 Assembly Hall of the Cosmos Club, Washing- 

 ton, D. C, at 4:30 p. m., on Thursday, April 

 19th. 



Dr. Wm. Luther has been appointed director 

 of the observatory at Diisseldorf, in succession 

 to his father. Dr. Robert Luther, whose death 

 we were recently compelled to record. 



Professor S. W. Johnson has resigned the 

 directorship of the Connecticut Agricultural 

 Experiment Station after service of over twenty- 

 two years, and is succeeded by Professor E. H. 

 Jenkins, the vice-director. 



Professor Silas W. Holman, emeritus pro- 

 fessor of physics at the Massachusetts Institute 

 of Technology, died on April 2d. 



Professor St. George Mivart, the well- 

 known writer on scientific subjects, died in 

 London on April 1st, at the age of seventy- 

 three years. 



There died recently Major Fred. Mather, 

 one of the most prominent of American fish- 

 culturists. He was the author of many notable 

 contributions to the Reports of the Fisheries 

 of State and Government, long time an as- 

 sistant of the U. S. Fish Commission, indeed 



