THE FIELD TELEGRAPH. 



309 



Austrian engineers assert that on favorable ground they could do the 

 work in two hours. In most cases, of course, the advancing army 

 would have to repair the permanent lines which would be partially 

 destroyed by the retreating forces, and in this way twenty-five miles 

 of wire were often erected by the Prussians in a single day. As soon 

 as an army moves forward, the field-telegraph line previously erected 

 is taken down and recoiled on the drums, while a fresh line is laid 

 from the new headquarters to the nearest permanent telegraph. This 

 is done with a view to economizing the material, an enormous amount 

 of which would have to be carried with the army, if the lines it left 

 behind it in its advance were not removed, and the poles, wire, and 

 insulators, employed in their construction again utilized. The hand- 

 barrows of the Austrian telegraph corps are designed to be used in 

 recoiling as well as uncoiling the wire ; and for this purpose are fitted 

 with a crank-handle and ratchet-wheels, so as to enable a man to turn 

 the drum and wind the cable upon it. 



Besides the ordinary field-telegraph companies, the French army 

 includes a mountain-telegraph corps, organized with a view to opera- 



FiG. 8. 



I 



Fig. 7. 



Telegkaph-Pole. Sock- 

 et, AND Insulator. 



Wire-connector. 



Maeie Davy Bat- 

 tery. 



tions on the mountainous frontiers of the south, or to be ready to 

 carry a line over a range of hills in an ordinary campaign, thus avoid- 

 ing a long detour in the valleys, or securing lateral communication 

 with troops divided from the main army by the hills. As the moun- 

 tain line would have to be laid along narrow, rocky paths, and through 

 lofty passes, all carriages and wagons are dispensed with, and their 

 place is taken by a train of mules. In a mountain-telegraph company 

 several of the mules are each laden with two drums of the insulated 

 cable, the instruments and batteries are carried on pack-saddles on 

 the backs of others, and others again transport the baggage, provi- 

 sions, and forage of the company, and also a light tent to form a sta- 

 tion whenever messages are to be sent along the line. 



While the field telegraph afibrds a commander a rapid and certain 



