PRINCIPLES OF CONSTRUCTION. 



107 



It has been pointed out to the author by Mr. Charles 

 Bright, Assoc.M.Inst.C.E., who has specimens of the two parts 

 in his possession, that a portion of the sheathing of the first 

 Atlantic cable, made by Messrs. Newall, had a right-handed 

 lay, and another portion of the same cable, by Messrs. Glass 

 and Elliot, had a left-handed lay. The sheathing of the second 

 cable between Dover and Calais, laid byH.M.S. "Blazer," was 

 also constructed with a right-handed lay. 



Right-Handed Lay 



(as in Rope). 



Fig. 52. 



Left-Handed Lay 

 (as in Cable). 



In the manufacture of a large amount of cable for one 

 expedition, say 1,500 to 2,000 miles, several sheathing machines 

 are worked simultaneously, some taking the heavier and some 

 the lighter types. The light types can be sheathed at the rate 

 of nearly half a mile per hour, and the heavy types at 

 about half that speed, the average speed being nearly one- 

 third of a mile per hour. Working ten machines together 

 therefore about 40 miles of cable can be turned out per day of 



