Periodical Literature. 155 



sizes only where extra strength is not required. Fiber does not 

 stand water well but never imparts taste while some wooden 

 boxes impart taste. Rats gnaw fiber boxes more than wood but 

 theft is more common from wooden boxes. Both boxes are 

 largely made from different kinds of low grade material and may 

 be used over and over, by re-pulping the fiber box and using the 

 wooden box as it is and finally converting it into fuel. 



American Lumberman, Dec. 10, 1910. 



The most important specifications adopted 

 Wood for wood block paving by 43 representa- 



Paving tives of large cities from all over the 



Specification^. United States are as follows: 



The wood to be treated shall consist of 

 Long Leaf Pine, Norway Pine, Black Gum or Tamarack, but 

 only one species shall be used in one contract. Longleaf Pine 

 blocks shall be cut from sound timber, well manufactured, full 

 size, saw-butted, square-edged and shall be free from hollow 

 knots, worm holes, knot holes, through-shakes and round shakes 

 that show on the surface, and not have an average of less than 

 six annual rings to the inch measured radically. The other 

 species shall be of a first grade similar to that demanded for 

 Longleaf Pine. 



The blocks may be from 5 to 10 inches long but shall average 

 8 inches, three and one-half to four inches in depth according to 

 traffic, and 3 to 4 inches in breadth. All blocks in one street or 

 improvement shall be of equal size. A variation of one-sixteenth 

 of an inch shall be allowed in depth and one-eighth of an inch 

 in width. The blocks shall be treated with a specified grade of 

 oil, and contain not less than 20 pounds per cubic foot for pines 

 and tamarack, and 22 pounds for gum. 



The oil must be a coal tar product free from adulteration, 

 specific gravity of at least i.io at 38 degrees C, and not more 

 than 3 per cent, of the oil shall be insoluble by hot, continnous 

 extraction with benzol or chloroform. 



Blocks are to be laid on a sand cushion one inch in thickness 

 laid upon concrete foundation. Pitch or fine sand is to be used 

 as a filler. All expansion joints are to be laid along the curb 

 and traverse joints one-half inch in width every fifty feet along 



