6 INTRODUCTION. 



purpose for which it is fit will enter into that improved practice to 

 which we may look both for greater economy and greater efficiency. 



The object of this bulletin is to record more systematically than has 

 been done hitherto the knowledge which exists and which will help the 

 wood consumer in the choice of his material and in determining whether, 

 and if so why, a given stick will answer his purpose. Such inspection 

 requires, first, a knowledge of the gross structure and appearance, 

 which give indications of quality and behavior, and then, for finer 

 application, a knowledge of the minute anatomical or microscopic 

 structure. The minute structure will often explain the difference in 

 behavior of various kinds of wood, and a knowledge of it is almost 

 indispensable in distinguishing the various kinds. 



In the countries of Europe the kinds of wood used in construction 

 and manufacture are so few that there is but little difficulty in distin- 

 guishing them. In our own country the great variety of woods, and of 

 useful woods at that, often makes the mere distinction of the kind or 

 species of tree most difficult. Thus there are at least eight pines (of 

 the thirty-five native ones) in the market, some of which so closely 

 resemble each other in their minute structure that they can hardly be 

 told apart; and yet they differ in quality and should be used separately, 

 although they are often mixed or confounded in the trade. Of the 

 thirty-six oaks, of which probably not less than six or eight are mar- 

 keted, we can readily recognize by means of their minute anatomy at 

 least two tribes — the white and the black oaks. The distinction of the 

 species is, however, as yet uncertain. The same is true as to the eight 

 kinds of hickory, the six kinds of ash, etc. Before we shall be able to 

 distinguish the wood of these species unfailingly, more study will be 

 necessary. The key given in the present publication, therefore, is by 

 necessity only provisional, requiring further elaboration. It unfortu- 

 nately had to be based largely on external appearances, which are not 

 always reliable. Sometimes, for general practical purposes, this mere 

 appearance, with some minor attributes, such as color, taste, etc., are 

 together sufficient, especially when the locality is known from which 

 the species came, and in the log pile the determination may by these 

 means be rendered possible when a single detached piece will leave us 

 doubtful as to the species. In the market the distinctions are often 

 most uncertain, and a promiscuous application of names adds to the 

 confusion. To be sure, there is not much virtue in knowing the correct 

 name, except that it assists us in describing the exact kind of material 

 we desire to obtain. Nor is there always much gained in being able to 

 identify the species of wood, but that it x>redicates certain qualities 

 which are usually found in the species. 



In selecting material, then, for special purposes we first determine 

 what species to use as having either one quality which is foremost in 

 our requirements, or several qualities in combination, as shown by 

 actual experience or by experiment. 



