III.] THE CLASSIFICATION OF TIMBERS. S7 



elsewhere, or they are numerous and crowded, 

 whereas the vessels in the autumn zone are small 

 or few and scattered. 

 (i) The vessels on the inner side of the spring" wood in 

 each annual ring are large and conspicuous. 

 (Many of our European timbers come here.) 

 The various types are further distinguished by the 

 characters of the meduHary rays, and the 

 mode of distribution of . the vessels, fc., in 

 the autumn zone, 

 (i) Some of the medullary rays are broad, and 

 easily visible to the naked eye : 

 e.g, Quercus Robur^ &c., the Oak type, 

 (ii) All the medullary rays are alike, and fine. 

 (The further subdivision depends on the 

 arrangement of the autumn vessels, &c.) : 

 e,g, the Ash, Elm, Chestnut, and the 

 following Indian timbers : — Teak, 

 Cedrela Toona^ Melia Asedarach^ 

 Lagerstrmmia Regincs, &c. 

 (2) The vessels on the inner margin of the spring- 

 wood are not larger than elsewhere, but they 

 are more numerous and crowded than in the 

 autumn wood, and hence render this zone 

 porous in another manner. 



e,g. Plum, Elder, Lilac, Buckthorn, &c., 

 and the following Indian timbers : — 

 Santalum alburn^ Gmelina arborea, 

 &c. 

 (b) The annual rings are distinct, but the line of demarca- 

 tion is due to the close texture of the elements 

 composing the autumn wood, and not to con- 

 spicuous differences in the sizes or distribution 

 of the vessels, hence the annual zones appear to 

 be divided by firm thin lines. (Most of our 

 European timbers come here.) The chief types 



