294 TIMBER 



as little as possible allowed, but it is not much use, and 

 scarcely fair, to put into a specification for large-sized 

 timber that it is to be " free from sap," unless the engineer 

 or architect is prepared to pay a much larger price than 

 for ordinary timber, because, to attain this object, larger- 

 sized timber must be bought in the first instance so as to 

 allow of the timber standing the required size after the 

 sap has been cut off. This adds considerably to the cost, 

 for not only has the larger-sized timber to be paid for, 

 but the cost of sawing has to be added. 



As a rule for heavy work three 4-inch or four 3-inch tim- 

 bers are cut out of a 12- inch log, and there will be a certain 

 amount of sap on the outer sides and corners of two pieces 

 and possibly on the edges of the others. 



It would be much more satisfactory to define the amount 

 of sap allowable, as, for instance, " Sap is not to exceed 

 2 inches or 2J inches at the corners of timbers " in an 11 

 or 12-inch plank, thus : 



\ 



: . \ x 



FIG. 50. 



On no account should sap be allowed all over one side. 

 Smaller scantlings can by selection be got quite clear of sap, 

 and this is very desirable. The clause " the timber shall be 

 properly seasoned " would prevent the admission of objec- 

 tionable sap, for some kinds are worse than others. The 

 author does not agree with a distinguished engineering 

 expert who, in giving evidence some time ago, stated that 

 timber seasons in its transit from the Baltic, because, unless 

 the timber be partly seasoned before being put on board, as 



