NOTES ON FORESTRY. 



tance the height would be 25 feet; at 40 feet 



distance, 46 feet; at 60 feet distance, 68 feet; 



at 90 feet dis- 

 tance, 100 feet; 

 and if the distance 

 were 100 feet, the 

 height could not 

 be read off on the 

 board, but we 

 could treat the 

 100 feet as 50 

 feet, when we find 

 the line reads 56, 

 and twice this, 

 112, would be the 

 height, as is also 

 chronicled by a 

 dotted extension 

 of the board. 



These instru- 

 ments might be 

 made very cheaply 



at Eoorkee, if a number were called for at 



once. 



The form figure indicates the relation of the tree 



to a cylinder. 



In the diagram, fig. 1 is the type of a pine-tree, 



and being a true cone, its relation to a cylinder whose 



