The modern highly efficient steam pumping engine has developed gradually from Watt's Cornish pumping engine first invented in 1769, with many other types of power, so that the engineer has now a very considerable field to obtain the type of machine from, to suit the particular work it is required for.
Cast iron mains were first used about the beginning of the 19th century, and stea] mains in any quantity at a very considerably later date in the same century. One of the greatest differences between the practice of the ancient water engineers and those of more modern times is that the ancients used no form of filtration or efficient sedimentation, and that no chemicals were used for softening a hard water, for sterilizing a contaminated water, or to accelerate sediment tation, in fact, they had to depend on their source of supply only for obtaining a potable water.
About the end of the 18th, and beginning of the 19th, century, an agitation for a better water supply than that obtainable from con-laminated sources, such as the Thames, took place, and many forms of strainers or filter beds were experimented with, with varying success.
Text read from the printed page and cleaned; old type leaves the occasional error.