20 On the Principles and Methods [Jan.. 



attempt hitherto made to extract a useful manure from sewage 

 which, could be applied in a solid form has proved anything but a 

 failure. 



The Commission apt: lintel by the British Association to report 

 '• On the Treatment and Utilization of Sewage.'' states, with refer- 

 ence to the treatment of liquid sewage, that at fifteen of the places 

 which are sewered, wholly or partially, the liquid sewage is sub- 

 jected to treatment either by allowing it to remain for a time in 

 settling- tanks, from which the deposit is occasionally removed, as 

 at Burton-on-Trent, Birmingham, Epsom. Farnham. and Andover, 

 or by filtering, as at Uxbridge and Ealing. In eight instances 

 deodorizing materials are added, such as lime and carbolic acid, as 

 at Carlisle and Harrow. Lime alone is used at L inne 



and chloride of lime at Luton : perchloric! e of iron at Cheltenham : 

 perehloride of iron and lime at Northampton ; ferruginous clay 

 wetted with sulphuric acid at Stroud : and at Leamington the lime 

 treatment has lately been superseded by the A. B, C, method pro- 

 posed by Messrs. Sillar and TVigner. By this treatment the 

 sewage is clarified, and a deposit is separated which is sold as 

 manure. 



In regard to the effects thus produced, it is stated that at 

 Leicester the sewage runs off as pure as ordinary rain-water ; at 

 Eating it is said to be free from smell, colourless, and harmless to 

 vegetable or animal life ; at Str ■: Luton the effect is stated 



to be satisfactory : at Harrow the nuisance is said to be somewhat 

 mitigated : and at Abergavenny the stench is said to be abated by 

 the treatment of the sewage ; at Bury St. Edmunds upward filtra- 

 tion through charcoal and gypsum has been abandoned in favour of 

 costly irrigation; at Ban!: .ment of the sewage has failed ; 



at Hereford, where it was proposed to be adopted, it has not been 

 tried on the score of expanse : at Tunbrid.cre it is about to be tried ; 

 and at Hastings and Cambridge experiments are bein.sr made. 



TVith regard tc the relative advantages of solid and liquid 

 manure, supp-osing even that all the fertilizing properties of sewage 

 could be retained in a solid form, we cannot perhaps do tetter than 

 to quote the following extract from the ''Minutes of the General 

 Board ::' Health relating to Drainage and Sewerage of Towns, &c, 

 1852/ by whom the question seems to have been satisfactorily set 

 at rest : — ,; It is established by wide general experience that drained 

 land does not deteriorate, but increases in fertility, and maintains 

 its increased fertility from year to year, though washed through 

 and through by all heavy falls of rain carried away by the drains. 

 The rationale of this fact was displayed in the experiments prose- 

 cuted by Professor "^ay, ^hr:h show that upon the application of 

 manures in the liquid form the fertilizing elements do not escape 

 through the soil, but are retained bv it chemically. On the other 



