xviii Preface. 



due to a wish to avoid increasing the bulk of this volume 

 more than is actually necessary, and to a feeling that the 

 portions treating specially of Inductive Logic (which oc- j 

 cupied some space in the last edition) would be more 

 suitable to a regular work on that subject. I am at present 

 engaged on such a work. 



The publications which I have had occasion to notice 

 have mostly appeared in various scientific journals. The 

 principal authors of these have been Mr F. Galton and 

 Mr F. Y. Edgeworth: to the latter of whom I am also 

 personally much obliged for many discussions, oral and 

 written, and for his kindness in looking through the proof- 

 sheets. His published articles are too numerous for separate! 

 mention here, but I may say generally, in addition to thi 

 obligations specially noticed, that I have been considerably! 

 indebted to them in writing the last two chapters. Twd 

 authors of works of a somewhat more substantial character! 

 viz. Prof. Lexis and Von Kries, only came under my noticd 

 unfortunately after this work was already in the printer s! 

 hands. With the latter of these authors I find myself id 

 closer agreement than with most others, in respect of hiJ 

 general conception and treatment of Probability. 



December, 1887. 





