Pumping Stations. 139 



dry, except in a wet season, when, if necessary, both engines are 

 employed to pump away the extra rainfall. All the water pumped 

 up is discharged into the Canale d'Acqua Chiara, and Hows through 

 the Lake of Fondi into the sea. It may be stated that the quantity 

 of water hfted by the pumps has been ascertained to be about 

 27,000 gallons (equal to 112*5 tons) per minute, which is equal to 

 about \ of an inch of rainfall in 24 hours. 



The area of land drained is about 12,000 acres, of which at least 

 10,000 acres are at present kept dry and under cultivation. The 

 land reclaimed is a rich alluvial soil, mixed with clay, admirably 

 suited for raising all kinds of cereal crops, especially Indian corn. 

 Since it has been drained and cultivated there is decided improve- 

 ment, splendid crops are being raised, and the proprietors, far from 

 demurring to pay the land-tax, now willingly submit to an extra tax 

 for the drainage of their property, which lets freely at 5/. per acre. 



The house erected to contain the pumping machinery is situated 

 close to the Canale d'Acqua Chiara. Owing to the nature of the soil, 

 it was necessary to drive in piles on which broad foundations were 

 laid and walls built On each side of this building are the lateral 

 canals that bring the water from the marshes to the suction pipes of 

 the pumps, whence it is lifted and discharged into the large reservoir 

 constructed in masonry, which is in* communication with the Canale 

 d'Acqua Chiara, so that the water flows away direct to the lake. The 

 reservoir has sluices that can be closed should the water in the 

 Canale d'Acqua Chiara rise higher than the level of the water in the 

 reservoir. 



There are two horizontal boilers, each 18 feet long and 4 feet 

 II inches in diameter, with an internal flue 2 feet 7|- inches in 

 diameter, in which are placed five conical tubes \ at the back end of 

 the boiler there are thirty-one iron tubes. Each boiler has a heating 

 surface of 37 6 J square feet, and a fire-grate area of 12 square feet. 

 The working pressure is 70 lb. per square inch; and as a single 

 boiler is sufiEcient for supplying the steam to both engines, the 

 second is kept in reserve. 



The two horizontal steam engines that drive the centrifugal pumps 

 have one cylinder each of 13I inches in diameter, with is§ inches 

 in length of stroke, fitted with variable expansion valves, cutting off 

 steam at 0-175 of the stroke. The condensers and air-pumps are 

 placed behind the cylinders, being bolted to the same bed-plate, and 

 are worked direct by the piston-rods of the cylinders. In case the 



