650 PROCEEDINGS OF SECTION J. 



layers of cotton wound round them in opposite directions, and 

 were then drawn into a lead pipe which, with its wires was placed 

 in a cauldron containing a mixture of pitch, resin, and beeswax, 

 and boiled for twenty -four hours, by which time it was found that 

 the hot compound had thoroughly tilled the pipe. These wires 

 worked for a short time, the compound gradually lost its insulating 

 properties, and then, wires covered with cotton, over which was 

 a thick coating of shellac and other insulating varnishes, were 

 drawn into iron pipes. These and other somewhat similar methods 

 to insulate and protect conducting wires underground, continued 

 to be tried in England with very little success until 1846, when 

 the use of gutta percha as an insulator was experimented with, 

 first by Mr. C. W. Siemens, and afterwards by his brother Dr. 

 Siemens, in Berlin, where that scientist laid an underground 

 telegraph line about four miles long in 1847. This line was so 

 successful at first that similar works were enthusiastically pushed 

 on until over two thousand miles of gutta percha coated wii'e 

 were placed underground, these lines worked fairly well for two 

 or three years, after which period they began to fail and had to be 

 abandoned in favour of overhead wires. 



About the time Messrs. Cooke and VVheatstone were experiment- 

 ing in England, Professor Jacobi placed telegraph wires underground 

 near St. Petersburgh. These wires were enclosed in glass tubes, 

 the ends of which were cemented together. Very little success 

 was met with in this way, and Jacobi tried to insulate his wires 

 by winding indiarubber tape round them. He failed, however, to 

 secure an efficient telegraph line, and finally the wires in Russia, 

 as elsewhere, were fixed to poles overhead. 



The first telegraph line constructed in America by Professor 

 Morse, was an underground one. Copper wires covered with 

 cotton and shellac vai^nish were placed in lead pipes and laid under- 

 ground. These wires only worked for a very short time before 

 the insulation broke down, and they were taken out of the pipes 

 and placed on poles. A few years later another attempt was 

 made in America to place wires insulated with gutta percha under 

 ground. As was the case with Dr. Siemens' wii'es in Prussia, 

 these worked very well for about two years, when the gutta percha 

 perished and the wires had to be abandoned. 



Up to a very few years ago all telegraph wires in America and 

 on the Continent of Europe were overhead. In England Telegraph 

 Engineers never gave up trying to devise a successful system of 

 underground wires, all attempts being on the lines of Messrs. 

 Cooke and Wheatstone's plan, which was to form insulated wires 

 into cables, and draw them through pipes laid carefully in the 

 ground. 



The difference between the various attempts consisted chiefly 

 in the material used as an insulator and in the kind of pipes 

 employed. Lead pipes were tried at first but soon found to be 



