TIMBER PHYSICS METHODS AND AIMS. ,")7'.l 



An author! t\ . ug matters writes regarding tliia work: 



" Inasmuch us 8 current among engineers ami architects as information on tin- strength of tirnlier is 



really misinfoni 10 rat ion il designing in timber can In; done until something more reliable is furnished 



in this direction, lii ity for making a competent and trustworthy scries of -such tests is apparent. This is a 



work which the Mould undertake if it is to he impartial and general." 



A caioful il pertains to the, history and conditions of the growth from which the test pieces 



come, and of tin e physical examination, will distinguish these tests from any hitherto undertaken on 

 American limbers. 



The disk i i be studied to ascertain the form and dimensions of the trunk, the rate and mode of its 

 growth, the density n i wood, the amount of water in the fresh wood, the shrinkage consequent upon drying;, tho 



structure of 111. st detail, the strength, resistance, and working qualities of the wood, and lastly, its 



chemical const ii value, ami composition of the ash. 



Ill Bulletin <! \ ire introduced to the science of "timber physics" in the following language: 



Whenever h nma i lowledgein any particular direction has grown to such an extent and complexity as to make 

 it desirable for ivenience and better comprehension to group it, correlate its parts, and organize it into 



a systematic wlmle, \\ .ay dignify such knowledge, by a collective name as a new science or branch of science. 

 The need of such ..rg .ition is especially felt when a more systematic progress in accumulating new knowledge is 

 contemplated. In do. iug, therefore, tho plans for a systematic and comprehensive examination of our woods it has 

 appeared desirable to > ahlish a system under which is to be organized all the knowledge we have or may acquire 

 of the nature and be] of wood. 



To this new bra of natural science I propose to give the name of "timber physics," a term which I have 

 used first in my repot ir 18*7, when, in devising a systematic plan of forestry science the absence of a collective 

 name for this class o: nowledgc became apparent. 



While fore ontcmplates the forest and its components in their living condition, we comprise in timber 



physics all rthenomci. exhibited in the dead material of forest production. 



The practical -. icatiou of timber or wood for human use, its technology, is based upon the knowledge of 

 timber physics, and .ler this term we comprise iiot only the anatomy the chemical composition, the physical and 

 mechanical prop wood, but also its diseases and defects, and a knowledge of the influences and conditions 



which determine sti i.nre, physical, chemical, mechanical, or technical properties and defects. This comprehensive 

 science, couceivi : the name here chosen, although developed more or less in some of its parts, has never yet 



been dignified h a lal name, nor has a systematic arrangement of its parts been attempted before. It comprises 

 various groups of I. wledge derived from other sections of science, which are neither in themselves nor in their 

 relations to "lly developed. 



While plani pi uology. biology, chemistry, anatomy, and especially xylotomy, or the science of wood structure, 

 are more or less de 'peil and contribute toward building up this new branch of science, but little knowledge exists 

 in regard to [he iui '.elation between the properties of wood on one side and the modifications in its composition 

 and structure on tl 'tlwr. Kven the relation of the properties of various woods, as compared with each other, and 

 their distinct speci; peculiarities are hut little explored and established. Less knowledge still exists as to tho 

 relation of the com I ions which surround the living tree to the properties which are exhibited in its wood as a result 

 of its life function Suppositions and conjectures more or less plausible preponderate over positive knowledge 

 derived from exact iservatiou and from the results of experiments. Still less complete is our knowledge in regard 

 to the relation of piperties and the methods and means used for shaping or working the wood. 



The close int Nation of all branches of natural science is now so well recognized that I need not remind my 

 readers that hard .1 1 fast lines can not be drawn whereby each field of inquiry is confined and limited; there must 

 necessarily be an < f-rlapping from one to tho other. Any system, therefore, of dividing a larger field of inquiry 

 into parts is only a alter of convenience; its divisions and correlations must be to some extent arbitrary and varied 

 according to the | at of view from which wo proceed to divide and correlate. 



There are twJclinite and separate directions in which this branch of natural science needs to be developed, 

 and the knowled; omprised in it may be divided accordingly. On one side it draws its substance largely from the 

 more eomprchcns fields of botany, molecular physics, and chemistry, and on the other side it rests irpon investi- 

 gations of the woi material from the point of view of mechanics or dynamics. In the first direction we are led to 

 deal with the wo.-, material as it is, its nature or appearance and conditions; iu tho second direction we consider 

 the wood material-.! relation to external mechanical forces, its behavior under stress. 



The first !>; i largely descriptive, concerned in examining gross and minute structures, physical and chemical 

 conditions and pnerties, and ultimately attempting to explain these by referring to causes and conditions which 

 produce them, tis is a field for investigation and research by the plant physiologist in the laboratory in connec- 

 tion with studied' environment in the forest. The second part, which relies for its development mainly upon 

 experiment by tl . ;iginecr, deals with the properties which are a natural consequence of the structure, physical 

 condition, anil . iiical composition of the wood as exhibited under the application of external mechanical forces. 

 It comprises, thiofore. those studies which contemplate the wood substance, with special reference to the uses of 

 man, and forms itimately the basis for the mechanical technology of wood or the methods of its use in the arts. 



The correlaon of the results of these two directio s of study as cause and effect is the highest aim ami 

 ultimate goal, t ! philosophy of the science of timber physics. Timber physics, in short, is to furnish all necessary 

 knowledge of tl rational application of wood in tho arts, and at the same time, by retrospection, such knowledge 

 will enable us t produce in our own forest growth qualities of given character. 



