136 THE SCIENTIFIC PAPERS OF 



therefore, strongly maintained the base plate to be a most import- 

 ant feature in the construction of a telegraph post. Again, the 

 base plate enabled the load to be much more equally divided. If 

 a socket were carried down to the 6 feet limit into the ground, it 

 would be necessary to carry it, in order to be safely out of the 

 ground, 4 feet longer, and this would necessitate a cast-iron tube 

 of 10 feet and perhaps 12 feet in length. This would be too 

 ponderous a piece of metal to carry into countries where transport 

 was difficult. The cast-iron base was by far the heaviest portion 

 of the post he proposed, and by carrying the post in three parts 

 of conveniemt weight and size, mules and other country transports 

 were quite equal to the work. Captain Mallock had described the 

 method which he had used in India of making short into long posts. 

 and he mentioned it as an advantage in favour of the parliculai 

 construction which he had adopted in India. It was certainly an 

 advantage to be able to increase the height of a post when neces- 

 sary ; but it should be remembered that the base was the most 

 important part of the post, and if the base were carried to where 

 the post was required, this could be more satisfactorily effected ; 

 for, unless it was known beforehand whether the post was to be a 

 high one or a low one, it would be necessary to carry the strongest 

 base everywhere. The way he should generally manage was this : 

 There was one strength of post to support the line where it was 

 straight, and another strength of post for corners, known as 

 " stretching-posts." These corner posts bore half a ton generally 

 of horizontal strain brought to bear upon them, and the others 

 generally about 5 cwt. But if a higher post were required to cross 

 the road or otherwise, a stronger post was taken and a lighter tube 

 put upon it by being dropped simply upon it. By that means much 

 higher posts were obtained and the strains throughout were pro- 

 portioned to their strength. In that way he accomplished what 

 Captain Mallock gained in the Avay he described. He would still 

 draw attention to the fact that, although a great many varieties of 

 construction were talked about in reference to a telegraph pole, 

 yet in reality there could only be one construction in principle, 

 whatever were the variations in detail. There could be only one 

 construction to give the maximum of strength for a given height. 

 Then there were other considerations which ought to be attended 

 to. The post ought to be light, and ought to resist oxidation 



