PREFACE TO THE SECOND EDITION 



The chief differences between this edition and the first (1912) 

 are as follows: (1) The Key has been entirely rewritten and re- 

 arranged, several new woods are included and more of the common 

 names are given; (2) the lists of references and the general bibli- 

 ography have been brought up to date; (3) an Appendix has been 

 added which amplifies some of the subject matter of Part I, and 

 also includes considerable new data on wood structure. 



In grouping the woods in the Key more attention has been 

 given to their general similarity than to special features, thus 

 bringing together for effective contrast the kinds which are most 

 likely to be confused in practice. Attempt has been made to have 

 all of the descriptions comparable and, so far as permissible, to 

 make the gross characters the basis for separation. The micro- 

 scopic features are printed in smaller type than the others, to 

 avoid confusion and to simplify the use of the Key. 



It is comparatively easy to make a key for a given lot of wood 

 specimens, but to take into account the range of variation of each 

 wood is an extremely difficult task. Such a key must be the re- 

 sult of growth, of the accumulation of years of investigation and 

 experience, and must always be subject to revision as new data 

 and new material become available. To this end the author 

 would enhst the cooperation of all readers of this book. 



Samuel J. Record. 



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