PREFACE TO THIRD EDITION. 



THE only changes in the present edition consist in such slight 

 corrections and additions as my own use of the work and the 

 experience of my readers have suggested. To these latter I am 

 greatly indebted for their kindness in reporting errors and sug- 

 gesting improvements. Such errors will be found corrected, 

 and, so far as possible, the improvements adopted. Some of 

 these latter, indeed, are of such a character that they can hardly 

 be embodied without, in large part, entirely rewriting portions 

 of the work. To those who can appreciate the labor of thus 

 remodeling any considerable part of such a work consistently 

 with the rest, the excuse of insufficient time will probably be 

 considered valid. I trust some time to be able to embody these 

 suggestions also, and thus render the work more worthy of the 

 very kind reception which has been accorded to it. Meanwhile, 

 my thanks are due to those friends and readers who have thus 

 so kindly aided me, and I would solicit both them and such 

 others as I may hereafter add to the list, to send in such errors 

 as may still exist, and such suggestions as may yet occur. 



NEW HAYEK, AprU, 1879. 



