The direction in which the water flows through the pump is indicated by arrows. It enters the runner axially from both sides, in order to eliminate axial thrust, and after traversing the runner the water is discharged into a chamber fitted with

expanding guide-passages for the purpose of converting the kinetic energy of the water 'leaving the runner into pressure energy. This chamber is the special feature of the pump, and judging from the excellent results obtained, it much more

effectually produces the desired result than the ordinary whirlpool chamber mentioned in a previous paragraph. The reader should also notice the great care that has been bestowed on the design of the pump, in order to avoid sudden changes in the direction of flow, and in the cross-section of the passages.

In Fig. 6136 is shown a multiple chamber pump of the same design. The water in this instance enters on one side only of the runner; then, after passing through expanding guidepassages, it is brought round to the other side of the runner, and after passing more guide-passages, it goes on to the next runner, and so on.

The following results of a test of one of these pumps will serve to show what excellent results are obtained; the figures are taken from curves published in the maker's catalogue :—

The following results of a test by the author on a multiple Parsons centrifugal pump, driven direct from one of their steam turbines, may be of interest :

In a short overload trial the pump delivered about two million gallons of water per day at a head of 1000 feet (see Engineering, vol. ii. p. 86 (1903).

The centrifugal pump in the near future will probably play a very much more important part amongst water-raising appliances than it has done in the past. Until quite recently it was universally considered that it was only applicable to the lifting of large quantities of water through low lifts, but now such pumps are employed for lifts up to 1000 feet, with an efficiency as high as that of many reciprocating pumps. The wear and tear is very small, and there are no sudden variations in the flow which produce such troublesome effects in the mains of plunger pumps.