114 NATURE-STUDY LESSONS. 



2. Split some and polish the surface. 



3. What is the material of which each block is com- 

 posed ? 



4. From what kind of tree has each been taken? 



5. Examine and describe the different surfaces of the 

 block. 



The white wood next the bark is the sapwood. The wood in the interior 

 is the heartwood. 



6. Compare the surfaces of various blocks, noting 

 their resemblances and differences. 



7. (a) Examine the circular surfaces of each block 



more closely. 

 (d) What is there in common about both areas ? 

 (c) Infer the way in which these rings have been 



formed, and the reason why the two areas 



are of different colors. 



8. (a) During what season of the year does a tree 



grow? 

 (<J) What conditions of the growing-time are the 



most favorable for growth? 

 (c) Infer, then, the reason why some of the rings 



are thicker than others. 



9. Examine a cylinder cut fresh from a young tree 

 to determine which of the rings has grown last. 



10. Observe the sap between the bark and woody part. 



B. Medullary Bays. 



11. (a) How does a tree show a record of the different 



periods of its growth? 

 (d) What means have you of judging of the age of 



a tree ? 

 (c) Compare the width of the rings In the various 



cylinders and infer which tree grew fastest. 



