72 JOURNAL OF FORESTRY 



used, and further test was made by relaying one of the worn-out sec- 

 tions with a thoroughly good grade (Grade A) of Douglas fir. The 

 remainder was filled with regular yellow pine blocks supplied by the 

 city. 



After seven years' service the fir is beginning to wear and broom, 

 and rapid increase in the area of local depressions was noted during 

 the last two years. "While these depressions are not deep at present, 

 the area afifected is in marked contrast to the surface of the yellow pine 

 portion laid at the same time." 



The results are summarized as follows : 



(1) Considering the species in sections 1 to 10, the order of efficiency of serv- 

 ice is as follows: (a) Longleaf pine, (b) white birch, (c) eastern hemlock, 

 (d) tamarack, (e) Norway pine, (f) western larch. 



(2) Since the relaid Douglas fir has only been in service 7 years, a good com- 

 parison of this wood cannot be made with the woods which have been in use 

 for a period of 12 years. At present the depressions and wear of this species 

 are from two to three times as much as that of the longleaf pine portion laid at 

 the same time. 



(3) For most of the species the depressions were very slight during the first 

 4 or 5 years' service. After this period the depressions increased at a very 

 rapid rate. 



(4) Sections 12, 13, and 14 showing wearing qualities of Norway pine which 

 compare favorably with longleaf pine and white birch. These sections probably 

 give a better comparison of the durability of this species than does Section 1, 

 which is subected to unusually severe traffic conditions on account of its shape 

 and location. 



(5) The western larch sections have the greatest percentage of area affected 

 by depression. This is also one of the species which shows the heaviest wear. 



(6) The order of the species beginning with that showing the least wear is 

 as follows : White birch, longleaf pine, Norway pine, tamarack, eastern hem- 

 lock, and western larch. 



(7) The presence of sapwood did not seem to be an important factor affect- 

 ing the duability of the pavement. 



(8) The various lengths of blocks employed had no apparent influence on the 

 wearing qualities of the pavement. 



(9) Less joint wear was noted in sections laid at 45° and 675^° than in the 

 section of blocks laid at an angle of 90° with the curb. 



S. J. R. 



Service-Test Records of Treated Cross-Ties on the Burlington 

 Railroad. By J. H. Waterman. In Proceedings of the fifteenth an- 

 nual meeting of the American Wood Preservers' Association. 1919. 

 Pp. 230-239; 



Mr. Waterman, Superintendent of Timber Preservation of the C, 

 B. & Q. R. R., presented some data to the convention and made many 



