APPENDIX II. 

 THE MICROSCOPIC EXAMINATION OF WOODS. 



IT is generally recognised that much more trustworthy evidence as 

 to the identity of out-of-the-way woods can be obtained by a 

 microscopic examination than from reports of native opinion or rule- 

 of-thumb tests applied by lumbermen or unscientific traders. Such 

 microscopic examination, it is true, will not always enable us to refer 

 an undetermined wood even to its Natural Order, and will in many 

 cases fail to discriminate between the species of one genus ; but, on 

 the other hand, it will often afford, in addition to the evidence of 

 identity, much valuable information as to strength, durability, or 

 other reasons for suitability or unsuitability. 



No one need be deterred from having recourse to this method of 

 examination by any alarm as to its technical difficulties or expense. 

 Though even an examination of a planed surface of wood with a 

 pocket lens may give useful suggestions, a thin transverse section 

 examined under the slightly higher powers of a compound microscope 

 will afford vastly greater information. Any ordinary microscope 

 costing from three to seven guineas will suffice ; but it is desirable to 

 have a wide simple stage and a triple or double nose-piece carrying, 

 preferably, objectives of 1^ in., ^ in., and in. focus. 



The preparation of the sections is not difficult. It is quite unnecessary 

 for the ordinary purposes of study to make them of anything like the 

 superficial dimensions of the beautiful preparations of Herr Burkart or 

 Mr. Hough. All that is requisite is to get a transparent section, across 

 the grain, embracing a few annual rings, though it is well to have, 

 either in one or in more than one section, the pith or structural centre 

 and some of the sapwood as well as the heartwood. The best results 

 will be obtained with well-seasoned wood. The end of the specimen 



