909 



II.— Physical rnopERTiER, i. e. properties based on niolccular (physical) constitntion. 



(a) Exterior appi'nnnice. 



Snrli j)ro)>('rtie.s as can ho obscrveil through the unaided senses, as color, 

 gloss, grain, loxtnre, smell, resonance. 

 (h) Material condition. 



Such properties or changes as are determined by measurements, as density 

 or weight, water contents and their distribution, volume and its changes 

 by shrinkage and swelling, 

 (c) Classif cation of woods according to p/u/.?ico-*ec/mico J properties, i. e. sueli ithys- 

 ical properties as determine their application in the arts. 

 III. — Chemical PKori;in'iKs, /. e. properties based on atomic (chemical) constitution, 

 (a) General chemical analysis of irood (qualitative and (iiiantttative). 



Here would bo discussed the chemical constitution ol'ilitiereut woods and 

 different parts of trees and its changes duo to physiological processes, age, 

 conditions of growth, etc. 

 (h) Carhohijdrates of the wood. 



Here would be more specially discussed cellulose and lignin, cork forma- 

 tions, organic contents and their changes, and such properties as predicate 

 the fuel value of wood, its manufacture into charcoal, its food value, pulpin"- 

 qualities, etc. 



(c) Extractive materials. 



A knowledge of these underlies the application of wood in the manufacture 

 of tan extracts, resin, and turpentine, tar, gas, alcohol, acids, vanillin, etc. 



(d) Antiseptic materials. 



A knowledge of those chemical properties Avhich predicate durability and 

 underlie processes of increasing the same, 

 (c) Mineral constituents. 



A knowledge of these in particular will establish the relation of wood 

 growth to mineral constituents of the soil and also serve as basis for certain 

 technical uses (potash). 

 IV.— Mechanical properties, i. e. properties based on elastic conditions exhibited 

 by the aggregate mass under intiueiu'e of exterior (mechanical) forces, 

 (a) Form chanf/es without destruction 0/ coAe.sio*?, commonly called elasticity, flexi- 

 bility, toughness. 

 (6) Form changes with destruction of cohesion, commonly called strength (tensile, 

 compressive, torsional, shearing), cleavability, hardness. 

 V. — Technical properties, i. e. propertio^s in combination. 



Here would be considered the woods with reference to their technical use, 

 their application in the arts, which is invariably based upon a combination 

 of several physical or mechanical properties. 

 VI.— Diseases and faults. 



Here would be treated the changes in structure and properties from the 

 normal to abnormal conditions, due to iuiluences acting upon the tree during 

 its life or upon the timber during its use. 

 VII. — Relation of properties to each other. 



Here would be discussed the connection which may be established between 

 structure, physical, chemical, and mechanical jiroperties, and also between 

 these and the conditions of growth uiuler which the material was produced. 

 The philosophy of the entire preceding knowledge would here be brought 

 together. 



