TIMBERS. 



17 



All timbers require to be straight in one way — in 

 the plane of their side, and the sides generally to 

 be square. The under measures embrace timbers of 

 appropriate size for vessels from 50 to 500 tons re- 

 gister ; it is seldom that merchantmen are required 

 under or above this size. Of course, large war- 

 vessels require timbers of larger dimension. The 

 corresponding timbers of vessels of different size are 

 nearly similar figures, and the length of their re- 

 spective lines not far from being in the ratio of the 

 cube root of the tonnage — a little deeper and thicker 

 in the smaller vessels. When timbers are formed of 

 larch or pine, they require to be a little more in dia- 

 meter than when of oak. 



B 



