242 



INDUSTRIAL PLANTS 



Fig. 227.— Poat-nioss (Sphag- 

 num cymhifoiium, Peat- 

 moss Family, Sphngnaccw). 

 14, plant in fruit, 1. 15, 

 spore-case, with lid still in 

 place, i. (Kern or.) — 

 Plants soft, yellowish 

 green or purplish; "fruit" 

 dark brown. Native home, 

 throughout the world in 

 bogs and peat swamps. 



less needful than clothing. Both 

 materials serve us mainly by their 

 mechanical strength, but with this 

 difference, that whereas a fiber of- 

 fers but little resistance except to 

 stretching, a piece of wood main- 

 tains its form but little changed 

 against severe mechanical strains 

 of whatever sort. Hence the great 

 use of wood for support in struc- 

 tures for shelter, storage, transpor- 

 tation, and repose; and its wide 

 application to innumerable minor 

 uses. The ready separation of 

 vegetable fibers and the facility 

 with which they may be twisted 

 and interlaced is matched by the 

 comparative ease with which wood 

 may be shaped and joined. 



The great importance of the 

 wood-working trades, carpentry, 

 joinery, turnery, and carving in- 

 dicates something of the extent 

 of our dependence upon the ma- 

 terial in which they work. A 

 further idea of the usefulness of 

 this material may be gained from 

 a brief review of the more impor- 

 tant classes of things which are 

 made wholly or in part of wood, 

 and of the qualities they especially 

 require in the material used. 



Buildings require different qual- 

 ities in the frame, the exterior and 

 the interior finish. Strength, ease 

 of working, and availability in 

 large dimensions are the main 

 needs for the framing timbers; re- 

 sistance to weather or adaptability 



