

Proceedings, &c., for 1885. 167 



of interlaced boards along the whole length. Lime- water, con- 

 taining one ton of lime per million gallons, is poured in by the 

 engine just below the screen. At the end of the race are the 

 settling ponds, which consist of two portions, used alternately, each 

 taking about a fortnight to fill with sludge. When one pond is 

 full the flow is turned into the other, and the sludge is pumped 

 into the filters. These are enclosures of brick, about 4 feet in 

 height, 6 feet wide, and 20 feet long. The floor is covered with 

 a layer of coke. In these the water is allowed to drain off till the 

 sludge can be dug out. The white sludge is now spread on an 

 iron drying floor to a depth of about one foot, and dried by fire. 

 The result is a layer of about 4 inches of white cracked material, 

 about the size of half bricks. These are burned in kilns, with a 

 little fuel (themselves supplying most of it), and the product of 

 this process is ground in a Chilian mill, and called Portland 

 cement. Its tenacity is about 300 lbs. per square inch. The 

 water from the settling ponds runs over a shoot into the river. 

 Beside this one is a second shoot for testing the purity of the 

 water. It is lined with glazed white bricks. To test the colour, 

 about 4 inches of water is run over the test shoot ; the inspector 

 should see no perceptible colour. Even then, however, it might 

 not be amiss to subject the water to a careful chemical and micro- 

 scopical examination at times, in order to ensure purity. When 

 sewage comes to the works with more than a certain proportion of 

 water it is allowed to flow direct into the river. 



Perhaps the most elaborate sewage works are those at Salford, 

 Manchester. The profits, however, seem to be very small, if any. 

 At this place closet pans are in use, which are emptied into air- 

 tight carts, in which they are carried to the works. The nightsoil 

 is there deposited in large iron cylinders. These are heated by 

 steam, and the contents dried into manure. The steam for this 

 purpose is generated in boilers, of which the fuel is part of the 

 town refuse from the dust carts. The rest of the rubbish is treated 

 with sulphuric acid, and gives a good manure. The nightsoil 

 manure is worth £3 per tori. At times loads of condemned fish 

 are brought to the works. The oil is extracted from them, and 

 the residue is manure worth £9 per ton. The oil and such grease 

 as comes from other sources is made into soap and candles. 



At some works near the last the system is not nearly so elaborate. 

 The nightsoil is discharged into a large reservoir, the rubbish 

 sifted in an inclined cylinder. The ashes are thrown in among 

 the soil of the larger pieces burnt in destructors. The nightsoil 

 is then taken up the canal in large barges as manure, and the 

 cost of removal is paid by the sale of the soil. 



One more interesting case claims our notice. Part of the 

 fashionable seaside town of Eastbourne lies below the high water 

 mark, and at times a high tide would force back the sewage in the 



