SHOUTEB ARTICLES AND DISCUSSION. 



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 379 



SHOETER AETICLES AND DISCUSSION, 



DE MORGAN AND CHARACTER- 

 ISTIC CURVES OF COMPOSITION. 

 To the Editor: In his quotation 

 from Augustus De Morgan in reference 

 to the application of the law of aver- 

 ages to the detection of authorship and 

 in his remarks thereon (see the De- 

 cember number of this journal) Dr. 

 Raymond Pearl is, unconsciously of 

 course, guilty of the exact fault which 

 he, by implication at least, attributes 

 to others; namely, ignorance of the 

 work of previous writers upon the same 

 subject. As his note seems to invite 

 others to share with him in that igno- 

 ranee, it may be desirable to explain, 

 once more, that it was this very sug- 

 gestion of De Morgan's that started 

 the investigation of more than twenty 

 years ago; that in the presentation of ! 

 the first results to the American Asso- 

 ciation for the Advancement of Science, 

 De Morgan was fully credited with the 

 idea; in the publication of these re- 

 sults in Science (about 1885) indebt- 

 edness to De Morgan was distinctly 

 acknowledged; also in subsequent pub- 

 lications and papers, the latest being 

 an article in a recent number of this 

 journal (August, 1904) ; — all of which 

 can easily be seen and known by 

 anybody who cares enough about 

 the subject to look it up. In the 

 first, and, as far as I know, the only 

 thorough test of De Morgan's idea, 

 made more than twenty years ago, it 

 was found to be difficult, perhaps im- 



possible, to discriminate among authors 

 by means of simple 'Average word 

 lengths,' as suggested by De Morgan. 

 The scheme for the graphic display of 

 the variations in the average frequency 

 of occurrence of words of different 

 lengths was then devised, proving to be 

 a vastly more powerful means of re- 

 vealing peculiarities of composition. 

 This is the only feature of the work 

 which has been claimed as original, and 

 the results of an exhaustive application 

 of it were published in 1901, confirming 

 me in my confidence in the truth of the 

 general principle stated by De Morgan, 

 though not in the value of the specific 

 application of it suggested by him. 



I believe that the scheme of analysis 

 by ' Characteristic Curves,' devised a 

 quarter of a century ago, has been ' re- 

 discovered ' one or twice since; but it 

 should never be overlooked that the 

 germ of the thing was in a brief re- 

 mark that I found in that now, but 

 never-ought-to-be-out-of-print book, the 

 'Budget of Paradoxes.' The ' Memoir ' 

 from which the letter is quoted by Dr. 

 Pearl did not appear until many years 

 later. As I now remember it, the 

 original suggestion was much less 

 elaborated than in the letter, which I 

 think I have never seen before. 



I do not understand why Dr. Pearl 

 calls this the ' Sherman Principle.' 



T. C. M. 



Rome, Italy, 



December 17, 1904. 



