UNDERGROUND CABLES. 543 



from both shores. From side to side it is no more than fifty miles, and the Pak- 

 chan River, on the western coast, and the Htassay on the eastern, afford the 

 ready means of further reducing it. The distance, therefore, over which it would 

 be necessary to cut a canal would probably not exceed thirty miles. The neigh- 

 boring districts are known to be fertile and to contain great mineral wealth. A 

 tin mining company has been established for more than ten years at Malewon, on 

 the Pakchan, and gold has been found in the neighboring stream of the Lenya. 

 So far as known the engineering difficulties are not of a stupendous character, 

 and pohtical drawbacks and considerations fortunately do not exist. 



The French appear to have taken the lead in proposing this important com- 

 mercial short-cut, and, if the opinion of the London Times is well founded, the 

 Government of British India will not decline to actively participate in its execu- 

 tion. — Scientific American. 



THE NEW TAY BRIDGE. 



Plans for the new Tay bridge are now on exhibition in Edinburgh for inspec- 

 tion by intending contractors. The new bridge is to be built on the girder prin- 

 ciple, four brick arches next the shore on the south side, each having a span of 

 50 feet; the girder work commencing with a span of 118 feet from centre to cen- 

 tre of the piers, is continued with ten spans of 129 feet and thirteen spans of 145 

 feet; this reaches the navigable portion of the channel. Here are eleven spans of 

 245 feet and two spans of 227 feet; the first four of these spans are 77 feet above 

 high-water mark. From this point the bridge falls at a gradient of one in 114, 

 there being one span of 162 feet, ten of 129 feet and six inches and one of 127 

 feet and six inches. The bridge is to be constructed for a double line of rails; 

 foundation will be formed of wrought-iron, cylinders filled with concrete, with 

 brick-work eight feet above high-water mark. Two piers are then formed of 

 wrought-iron pillars braced together, connected with each other near the top ; 

 ..the platform of the bridge is of wrought-iron. 



UNDER-GROUND CABLES. 



The telegraph pole and wire nuisance which prevails in all cities will proba- 

 bly soon be abated to a great extent. In New York and Chicago the wires are 

 rapidly being put under-ground, and it is possible that the time is coming when 

 the under-ground method of telegraphing will be in vogue all over the country, as it 

 is now pretty generally in Germany. In Chicago four miles of this cable have been 

 laid and the work is being pushed as fast as possible. Under-ground telegraphing 

 has been a problem difficult to solve, and it is only recently that it has been brought 

 to anything like perfection. The method in use at Chicago consists, in brief, of 

 a cable made up of No. 12 copper wire, inclosed in a lead pipe, resting on a cov- 



