.sv/v- \VII.UAM SII:MI-:.\S, I-.R.S. 135 



jv.ii Ibs. or 90 Ibs. His (Mr. Siemens's) base plate, which was a 

 disht.-d \\ruught-iron plate, weighed 80 Ibs. Therefore a saving 

 of r,o Ibs. in wci^lii was effected. But that was not all. Major 

 Webber had said that he (Mr. Siemens) derived the strength of 

 his post from the base plate, but that he (Major Webber) derived 

 his strength 2 feet from the bottom. Therefore Major Webber's 

 post, the siime absolute height out of the ground, of the same ab- 

 solute length between the turning-point of his level of 18 inches, 

 to be of really the same height out of the ground, ought to be 

 18 inches longer than his (Mr. Siemens's). Not only did he (Mr. 

 Siemens) save 54 Ibs. in absolute weight (supposing he made his 

 tube of the same strength as Major Webber's), but he was enabled 

 to raise the strength of his post as if he had it 18 inches longer. 

 15ut the base plate had another advantage. If it were put into 

 the ground, and the earth filled up over it, the post was absolutely 

 fixed. The strain might come in sufficient severity to move the 

 base plate, but the moment the strain left it the earth fastens it 

 down. A mere iron or wooden post put into the ground, if once 

 shaken, would always be loose, and the iron post had a very great 

 disadvantage as compared with the wooden post, because it had 

 less surface, and that surface was so smooth that it slipped through 

 the earth much more readily than wood. The advantage of the 

 base plate was that the weight of earth itself fastened the post. 

 With regard to the amount of earth, that, he thought, according 

 to Major Webber's opinion, seemed to be much lighter than was 

 absolutely requisite. He had never found an iron post put 2 feet 

 8 inches in the ground to be torn up. The line in which the earth 

 would pass, if the strain were applied, would be such as to render 

 the earth on the base plate not only a dead weight, but the earth 

 would be lifted away at an angle of about 45 degrees, and the fric- 

 tional resistance to moving the earth would come in aid of that 

 dead weight. It was quite remarkable how firm posts of this descrip- 

 tion stood in the ground. In fact, it was only imitating nature. If 

 a tree was uprooted, it would be found that it took its strength near 

 the surface of the ground. The roots spread at once, and if the enor- 

 mous pressure brought to bear against a large tree standing alone 

 in a field with a gale blowing against it were calculated, it would be 

 surprising to account for its holding its ground against a pressure 

 of perhaps from 40 tons to 100 tons acting against it. He, 



