188 



THE ELECTRIC TELEGRAPH. 



violence of the weather. Such supports have repeatedly been 

 constructed, hut their cost has always been a bar to their 



further employment. In 



India, in the early days 



of telegraphy, many such 



pillars were erected, and 



in 1852 a line from Treviso 



to Tagliamento was entirely 



supported by obelisks 4J 



metres high, as shown in 



Fig. 97. In Switzerland 



they have begun in good 



earnest the use of iron 



posts, the line from Olten 



to Sissach, lately erected, 



being supported entirely 



by iron posts. In Prussia 



also the necessity has 

 lgf been fully comprehended 

 of discarding wood and taking to some 

 more durable material. Mr. Borggreve has 

 employed, on the line between Grera and 

 Weissenfels, a pillar constructed of a 

 wrought-iron tube, 1| inch diameter, fixed 

 with lead into a socket on ike top of a 

 freestone pillar, 6 feet high and 8 inches 

 square. 



The iron post of Mr. "W. Siemens is coming 

 Very generally into use abroad, and will no 

 doubt find employment in England also, 

 when the necessity of a durable post becomes 

 thoroughly appreciated. 



This post is formed of two tubes, one set 

 upon the other, and tlie bottom of the lower 

 one made fast to a bent plate of iron buried 

 in the ground. One of them is shown in Fig. 

 98. The base consists of one of Mr. Robert Mallet's 

 patent buckled wrought-iron plates, 1 foot 9 inches square, 



98> 



