rREYENTIXG THE IXKOAD OF WAVES. ZoD 



the speed of a locomotive, tlieir effects are in the highest 

 degree appalling; and iron bolts are snapped, and massive 

 timbers crashed beneath their violence. 



PREVENTIXG THE IXROAD OP WAVES. 



To prevent the inroads of lake waves upon land, the 

 remedies must vary with circumstances. The difficulty 

 would be small if the Avater always stood at the same 

 height. The greatest mischief is ULSually -done when they 

 rise over the beach of sand and gravel which they have 

 beaten for centuries. Wooden bulwarks soon decay. 

 Where loose stones can be had in large quantities, form- 

 ing sloping rip-rap walls, they may be cheapest ; but they 

 are not unfrequently placed too near lovr-water mark to 

 protect the banks. Substances which offer a gradual im- 

 pediment to the waves are often quite effectual, though 

 not formidable in themselves. It is curious to observe how 

 so slender a plant as the bulrush, growing in water several 

 feet deep, Avill destroy the force of waves. If it grew 

 only near the shore, where the water has progressive mo- 

 tion, it would soon be dashed in heaps on the beach. 

 Parallel hedge-rows of the osier willow, protected by a 

 wooden barrier until well grown and established Avould, 

 in many cases, prove efficient. 



Stones and timber bulwarks are often made needlessly 

 Fig. 261. liable to injury by 



being built nearly 

 perpendicular, and 

 the waves break 

 suddenly, and with 

 full force, like the 

 blows of a sledge against them. A better form is show^n 

 in fig. 261, where a slope is first presented, to weaken their 

 force without imposing a full resistance, and their 

 strength is gradually spent as they rise in a curve. A 



