432 



SCIENCE. 



[N. S. Vol. XVI. No. 402. 



how the ii-regulav shadows visible with low 

 power telescopes have led up to the present 

 network of lines seen through glasses of high 

 power. J. J. Stevenson discusses 'University 

 Control,' pleading for a reorganization of the 

 present system and for a separation of educa- 

 tional and business management. 'The 

 World-view of a Scientist: Ernst Haeckel's 

 Philosophy,' by Frank Thilly, concludes that 

 so far as philosophy is concerned Haeckel is 

 still in his first childhood. M. C. Marsh treats 

 of 'Eels and the Eel Question,' showing the 

 uianj'' misapprehensions that have been held 

 concerning these fishes and their reproduc- 

 tion. It is a pity that he did not round out 

 tlie interesting article by telling what is ac- 

 tvially known regarding their history. Theo. 

 Gill gives 'The Story of a Word — Mammal,' 

 showing that the etymology commonly given 

 is incorrect and that it was coined by Lin- 

 nsEus to denote that class of animals marked 

 by having niamma^. In 'A Year of Weather 

 and Trade in the United States' R. DeC. 

 Ward shows how intimately the two are con- 

 nected. Frederick Adams Wood continues tlie 

 discussion of 'Mental and Moral Heredity in 

 Eoyalty' and there is a reprint of Sir Isaac 

 Newton's 'A New Theory of Light and Col- 

 ours.' In ' The Progress of Science ' is an ex- 

 tremely good article on 'Science in American 

 Journals' which makes plain the need of in- 

 telligent supervision of scientific articles of 

 a popular character. 



DISCUSSION AND CORRESPONDENCE. 



'EFFECTIVE FORCES.' 



To THE Editor of Science: In a review of 

 ' Some Eecent AVorks on Mechanics,' in Sci- 

 ence, October 11, 1901, reference is made to 

 the use of the terms ' force of inertia ' and 

 ' effective forces ' in two of the books luider 

 consideration, and the opinion is expressed 

 that these terms ' are properlj' going, if not 

 well nigh gone, out of fashion,' and that 

 'tliey seem doomed to be replaced by the more 

 suggestive term "kinetic reaction," or "mass 

 reaction."' It is to be feared that nothing 

 is gained by argumentation upon questions of 

 this kind, and I have no desire to revive a con- 

 troversy which long ago occupied much space 



in the pages of Sciisnce and elsewhere. But 

 since the question has been raised in connec- 

 tion witli my own use of the term ' effective 

 forces,' I would be glad to record my reason 

 for preferring this to the more modern and 

 ' suggestive ' terms favored by tlie reviewer. 

 This reason is that it seems imwise to replace 

 an established term by another unless the 

 latter is a better description of the thing 

 designated. And however imperfectly the 

 term effective force describes the quantity to 

 which it is applied, no term has been sug- 

 gested which serves the purpose any better. 

 ' Kinetic reaction ' and ' mass reaction ' are, 

 indeed, suggestive, but it is for this very 

 reason that they are objectionable, for they 

 seem to suggest an erroneous conception of 

 the third law of motion. In this respect they 

 must, I thinlv, be classed witli the term ' force 

 of inertia.' 



May I add a word regnvding the reviewer's 

 remarks upon the theory of dimensions. He 

 rightly emphasizes the value of this theory 

 as a means of avoiding and of detecting 

 errors in pliysical equations, but in citing a 

 sentence from my book as an example of an 

 eiToneous interpretation of a constant which 

 is immediately detected by the theory of 

 dimensions he has, I think, been over hasty. 

 The sentence quoted is strictly correct. 



L. M. HosKiNS. 



Stanford Unix-ersitt, Cal., 

 August 10, 1902. 



eefekence books in nomenciature. 

 To THE Editor of Science: In the issue of 

 Science for August 29, 1902 (p. 354), tmder 

 the heading 'Scientific Nomenclature,' Mr. R. 

 H. Harper gives a list of thirty-two words 

 used in current scientific papei-s which he was 

 not able to find in Webster's International 

 (1S90), the Century Dictionary (1902) or the 

 Universal or Encyclopedic (1S97). Being 

 loath to believe that some of the words listed 

 had wholly escaped the lexicographer refer- 

 ence was made to a 1901 edition of the Stan- 

 dard and to the Supplement of Webster's 

 International (1900), resulting in the finding 

 of definitions for thirteen of the terms. 

 Eleven of these definitions are given after the 



