THE TELEGRAPH. 
130 
proportion as the strain of the wires is greater (fig. 71). 
When this strain reaches a certain limit, either on account of 
the great number of the wires,, or by an increase of span, or 
because the angle formed by the direction of the wires is too 
acute, posts are connected in couples (fig. 72) by an iron bolt 
at the top, and again at the foot where they are placed further 
apart, and props are added when required. It sometimes 
happens, from the shifting nature of the soil, from the necessity 
of avoiding the smallest displacement of the wires, and from 
other causes, that even these methods of obtaining firmness 
prove insufficient. . 
Eecourse is then had to stays, that is to say, to ropes of 
twisted wires, attached at one end to the upper part of the 
posts, and at the other to existing fixed points, such as masses 
