22 TIMBER AND SOME OF ITS DISEASES. [cHAP. 



of value. In support of this statement it is only 

 necessary to call attention to the " Manual of Indian 

 Timbers," prepared for the Indian Government by 

 Mr. Gamble ; or to refer to the beautiful series of 

 wood-sections prepared by Nordlingcr. 



It is, of course, impossible in a small book like this 

 to do more than touch upon a few of the more 

 interesting points in this connection ; but I may 

 shortly summarize one or two of the more striking of 

 these peculiarities of timbers, if only to show how 

 well worth further investigation the matter is. 



Many timbers, from both tropical and temperate 

 climates, exhibit the so-called "annual rings" on the 

 transverse section ; but this is not the case with all. 

 Most European timbers, for instance, are clearly 

 composed of such layers ; but in some cases the 

 layers ("rings" on the transverse section) arc so 

 narrow and numerous that the unaided eye can 

 scarcely distinguish them, or the differences between 

 the spring and autumn wood are so indistinctly 

 marked that they may appear to be absent, or are at 

 least obscure, as in the olive, holly, and orange, for 

 instance. It is in the tropics, however, that timber 

 without annual rings is most common, possibly because 

 the seasons of growth are not sufficiently separated 

 by periods of rest to cause the formation of sharply- 



