TELPHERAGE 



257 



it has not yet been subjected to the test of actual traffic day by 

 day. At Weston, the vulcanite was used between layers of 

 Portland cement, the only objection to which is, that it takes some 

 time to set. The simple steel rod has been found preferable in all 

 ways to rope. We find that there is less friction, and less jar 

 with the rod, and ample flexibility ; it is also much easier to 

 secure. Moreover, a solid rod, with welded ends, can be made 



FIG. 1. 



FIG. 2. 



FIG. 3. 



so that the ends, where supported, are, to some extent undercut, 

 as is shown in the corresponding bulb angle-iron (Fig. 3) used 

 for rigid parts of the road ; this undercutting allows much 

 greater freedom of rolling than would be compatible with the 

 horizontal gripping wheels, especially when gripping wheels are 

 used which, like those in the model, actually hold on to the line, 



FIG. 4. 



so as to resist being lifted. A short piece, E, slightly insulated, 

 prevents the sections from being short-circuited by the wheels. 

 Fig. 4 shows the post and crosshead supporting the line. In the 

 1-inch example this design was fully carried out, and the posts 

 stood the cross strain due to the overhanging load perfectly. In the 

 five-eighth-inch line an attempt was made to cheapen the construc- 

 tion, but the posts, in wet weather, work at the foundations ; it is 

 VOL. n. s 



