THE MEASUREMENT OF PIECE PRODUCTS 



475 



third summerwood when averaging five or more rings of annual growth per inch, or 

 with not less than one-half summerwood in fewer rings, measured along any radius 

 from the pith to the top of the tie. Ties of coarse wood, with fewer rings or less 

 summerwood, will be accepted when specially ordered. 



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Ties for use without preservative treatment shall not have sapwood wider than 

 one-fourth the width of the top of the tie between 20 and 40 inches from the middle, 

 and will be designated as " heart " ties. Those with more sapwood will be desig- 

 nated as " sap " ties. 



Manufacture. Ties should be made from trees which have been felled not longer 

 than one month. 



