CROSSTIES PURCHASED AND TREATED IN" 1915. 7 



unfitted for this purpose because they did not have the proper decay- 

 resisting qualities or immunity from insect attacks. Such treatment 

 is often economical even with the woods that are more or less durable, 

 the added life in service more than paying for the increase in the first 

 cost. 



Most of the crossties treated by the steam railroads in the United 

 States are treated in closed cylinders permitting the application of a 

 high pressure and designed to secure a heavy absorption of the 

 preservative. 



The schedules furnished to the steam and electric railroads did not 

 request information as to the number of ties treated in 1915, but the 

 Forest Service gathered statistics for this year from all of the treating 

 plants in the United States. Table 8 shows the number of ties 

 treated by the preserving plants during 1915, by kinds of preservatives 

 and kinds of wood. 



Table 8. — Number of crossties treated by preserving -plants during 1915, by kinds oj 

 preservatives and kinds of wood. 



Kind of wood. 



All kinds . 



Oak..., 



Southern pine . 



Douglas fir 



Beech 



Western pine 1 . 

 Tamarack 2 ... 



Gum 



Birch 



Elm 



Maple 



All other 



Total. 



37,085,585 



16,885,517 



8,541,203 



3, 553, 854 



2, 933, 737 



2, 007, 609 



932, 038 



277, 886 



173,971 



50, 846 



36, 942 



1,691,982 



Zinc 

 chloride. 



17,819,284 



7, 954, 



3, 257, 



2, 760, 



100, 



1, 702, 



449, 



204, 



50, 



1, 338, 



Creosote. 



17,077,069 



Zinc chlo- 

 ride and 

 creosote. 



2, 182, 712 



7, 365, 673 

 5,243,516 



787, 247 

 2, 469, 202 



301,581 



390, 017 

 1,650 



173, 916 



36, 626 

 307, 641 



1, 565, 352 

 40, 122 



364, 535 

 3,861 

 91,496 

 71,583 



45, 763 



Miscel- 

 laneous. 



6,520 



1 Includes lodgepole pine and western yellow pine. 



2 Includes western larch. 



Since railroads often purchase large quantities of ties in one cal- 

 endar year which do not receive preservative treatment until one or 

 more years following, it is impossible to harmonize the data showing 

 purchases with those showing preservative treatment. Further- 

 more, some treated ties reported in Table 8 may have been pur- 

 chased by those roads which failed to report.' 



The treating plants reported a total of 37,085,585 crossties treated 

 in 1915, which is about 38 per cent of the total number of ties reported 

 purchased during that year. Of the total number of ties treated in 

 1915, 25,831,204 were hewed ties and 11,254,381 were sawed ties. 



Oak ties were treated in larger numbers than any other species, 

 contributing about 45 per cent of the total number treated. Southern 

 pine was second in importance, constituting about 23 per cent of the 

 total treated. Other species reported treated were Douglas fir, 

 beech, western pine, tamarack, gum, birch, elm, and maple. There 



