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of wire only. They are made either with four or six strands, 
each strand containing eight w^ires twisted round a hempen 
core; and it is presumed that a greater strength is thus 
gained with the same weight of material employed. Another 
advantage is, that on a strain being applied to the rope, the 
core of hemp, from its greater elasticity, gives way in exact 
proportion with the wire strands ; whereas if the core were 
made of the same substance as the strands, it would, from its 
being shorter, have to bear more than its due proportion of 
the strain ; and would of course be more easily broken. The 
hempen cores are saturated in a chemical solution, which, it is 
said, effectually prevents the corrosion of the metallic wires. 
The chief advantages possessed by these ropes over those 
of hemp, are stated by the patentee to be less bulk and 
weight for the same strength, combined with greater flexi- 
bility. Their prime cost is also less, and their durability 
greater. Indeed they are said to last four or five times 
longer than the hempen ropes. Flat wire ropes are manu- 
factured at Camberwell on the same principle ; but of these 
very little is either known or said. 
From a statement of trials made at Woolwich, in October 
last, it appears that Heimann's inch round wire rope, of 
six strands, with eight wires in each strand, and the wires 
No. 11 gauge, bore the same strain as a 10 inch hemp rope, 
(namely 20 tons) although the weight per fathom of the 
former was only 13^ lbs,, while that of the latter was 24 lbs. 
The price of the former is 8s. 4d. per fathom, of the latter 
9s. 8d. per fathom. 
In this instance, therefore, the bulk of the wire rope is 
nearly 60 per cent, less, its weight per fathom is nearly 50 
per cent, less, and its prime cost per fathom is about 14 per 
cent, less, as compared with hempen rope of equal strength. 
A smaller wire rope, 2| inches circumference, made of 
No. 16 wire gauge, bore the same strain as a four-inch hemp 
