506 



SCIENCE. 



[N. S. Vol. XX. No. 511. 



lowing tliis are ' Reflections suggested by the 

 New Theory of Matter,' by Arthur James Bal- 

 four ; a discussion of ' The Mathematical 

 Physics of the Nineteenth Century,' by Horace 

 Lamb ; ' Heredity and Evolution,' by William 

 Bateson ; ' The Perception of the Force of 

 Gravity by Plants,' by Francis Darwin ; ' The 

 Ethnological Work of Lane Fox,' by Henry 

 Balfour ; ' On Mountains and Mankind,' by 

 Douglas W. Freshfield; 'Correlation of Ee- 

 fl.exes and the Principle of the Common Path,' 

 by C. S. Sherrington ; and ' Invention and 

 Discovery,' by Charles A. Parsons. The num- 

 ber contains the index to Vol. LXV. 



Bird Lore, for September-October, contains 

 articles on ' President Roosevelt and Bird Pro- 

 tection ' ; ' A Woodcock at Home,' by E. G. 

 Tabor; 'October Bird Music,' by Earle Staf- 

 ford ; ' King Cole, a Biography,' by Susan M. 

 Morse ; the sixth paper on ' The Migration of 

 Warblers,' by W. W. Cooke, and the ' Climatic 

 Variation in Color and Size of Song Spar- 

 rows,' by Frank M. Chapman. There are 

 also book reviews and notes, the Audubon De- 

 partment and an educational leaflet on the 

 ' Screech Owl,' by William Dutcher. 



Beginning in January next, a new educa- 

 tional journal, entitled ' The Nature Study 

 Review,' will be published bi-monthly with Dr. 

 M. A. Bigelow, adjunct professor of biology at 

 Teachers College, Columbia University, as 

 managing editor. 



DISCUSSION AND CORRESPONDENCE. 

 THE METRIC SYSTEM. 



To THE Editoe of Science: I wish to ob- 

 ject to a statement recently made with regard 

 ' to the use of old names in countries that have 

 accepted the metric system. It has been said 

 that the common people in continental Europe 

 are not yet fully accustomed to the metric 

 system, and have partly retained the old 

 names in preference to the new ones. 



This is absolutely untrue, as far as it refers 

 to Germany. After the official introduction 

 of the metric system in that country, it took 

 a very short time — if not a fortnight, certainly 

 only a few months — to make the ' masses ' 

 familiar with it, and about a year after its 



introduction there was nobody but a few old 

 and decrepit people that had been unable to 

 master it. In fact, there was general rejoicing 

 on account of the riddance from the old and 

 cumbersome system. Indeed, a few of the old 

 words are occasionally used in Germany, but 

 only such that come very close to a metric 

 unit (' Pfund,' ' Maass '), and these are always 

 used in the metric sense, and nobody wants 

 to imply by this that he is opposed to the 

 metric system, or that he is ujiable to grasp it : 

 it is merely a variety of speech, and distinctly 

 individual or local. 



The whole discussion of the metric system 

 carried on recently in Science has been very 

 amusing to the writer, and has furnished stuff 

 for merriment to others. Is it actually the 

 case that the opponents of the metric system 

 believe that the American people are incapable 

 of accomplishing the identical thing that has 

 been done in Germany thirty years ago in a 

 surprisingly short time? Is it actually impos- 

 sible to obtain correct information about the 

 way it was done there, and about the conse- 

 quences and incidents connected with this 

 change? A. E. Ortmann. 



Pittsburgh, Pa. 



SPECIAL ARTICLES. 

 is matter to be abolished? 



Of late we have been hearing many intima- 

 tions that matter has had its day. Formerly 

 matter and its properties engaged the atten- 

 tion of the physicist. Later the ether was 

 discovered, and now we are told that the ether 

 and electrons are all that will be left, when 

 the new discoveries have been fully digested. 

 In connection with these statements I wish to 

 lay down a few propositions which may have 

 been overlooked. 



It does not appear that electricity has ever 

 been separated from something that has mass. 



The propositions that matter has mass, and 

 that a mass of matter has inertia, seem to me 

 to be fundamentally different from each other. 



If the inertia of matter can be accounted for 

 as an electromagnetic phenomenon, it may be 

 measured in new units. Instead of being 

 merely a mass phenomenon, it may be referred 



