CHAPTER XV. 



Iron in Sea-water Experiments made by Mr. Ronnie Experiments made by 

 Mr. Mallet Experiments made by Mr. Thwaitc Composition of Sea-salts 

 Analysis of Sea-water Fixing bolts in Masonry Anchor-bolts Experi- 

 ments made by Mr. Moore Experiments made by Mr. E. F. Miner Hold- 

 ing power of Drift-bolts in Timber Experiments made by the United 

 States Government Experiments made in connection with the Brooklyn 

 Lridge Experiments made by Mr. Tscharner Holding power of Spikes 

 Wire-rope fastenings -Clay suitable for puddle Puddling bottoms of Basins 

 Boring Surface friction on Cylinder Foundations Experiments made by 

 Messrs. Griber and Balzano Surface friction on Piles Resistance of different 

 materials to horizontal stress Sheet-piling Increase in resistance of Piles 

 due to quiescence Displacement of Ground by piling Composite piling 

 Screw-piles Screw-piling in unstable Ground Load on Piles Defective 

 Pile-heads Water-jet in pile-driving Water-jet in cylinder sinking Testing 

 stability of Ground Pressure on Ground under Dock-floors Equipment 

 Bollards and Wharf-moorings. 



Iron in Sea-water. Recorded experiments as to the superior 

 durability of cast iron as compared with wrought iron, when 

 exposed constantly to the action of sea-water, appear to be 

 somewhat conflicting. 



Mr. G. Rennie made experiments in 1836 on 1-inch cubes 

 of wrought iron, cast iron, and of bronze, with reference to their 

 eligibility for lighthouse purposes. 1 



The cubes being previously weighed, were plunged into a 

 saline solution considerably stronger than sea- water as follows : 



Grains 



Muriate of soda 122 



Muriate of magnesia 25 



Muriate of lime 6 



Sulphate of soda 30 



183 



Dissolved in 10i ounces of Thames water. 



The cubes were taken out of the water after being immersed 

 seventy hours in separate vessels. The cast iron was found to 



1 "Stevenson's Design and Construction of Harbour*," p. 180. 



