158 



Liquid Manure. 



soap-suds, very superior crops of grass on land of a very inferior 

 description.* 



I shall conclude with a few observations on the loss which the 

 cultivated lands of England incessantly sustain from the liquid 

 manure of the sewers of her cities and large towns — a question to 

 which I have before alluded in this paper, and which is not nearly 

 so well understood as is desirable. Thus, by carefully conducted 

 experiments and very accurate gaugings, it has been found that 

 the chief London sewers convey daily into the Thames about 

 115,000 tons of mixed drainage, consisting, on an average compu- 

 tation, of 1 part of solid and 25 parts absolutely fluid matters ; 

 but if we only allow 1 part in 30 of this immense mass to be 

 composed of solid substances, then Ave have the large quantity of 

 more than 3800 tons of solid manure daily poured into the river 

 from London alone, consisting principally of excrements, soot, 

 and the debris of the London streets, which is chiefly carbonate 

 of lime : thus, allowing 20 tons of this manure as a dressing for 

 an acre of ground, there is evidently a quantity of solid manure, 

 annually poured into the river, equal to fertilizing more than 

 50,000 acres of the poorest cultivated land ! The quantity of 

 food thus lost to the country by this heedless waste of manure is 

 enormous ; for, only allowing one crop of wheat to be raised on 

 these 50,000 acres, that would be equal to the maintenance (cal- 

 culating upon an average produce of 3 quarters of wheat per acre) 

 of 150,000 persons. London, too, is only one huge instance of 

 this thoughtless waste of the agricultural riches of the soil of 

 England ; from every other English city, every town, every ham- 

 let, is hourly passing into the sea a proportionate waste of liquid 

 manure ; and I have only spoken of the solid or mechanically 

 suspended matters of the sewerage ; the absolutely fluid portion 

 is still rich in urine, ammoniacal salts, soda, &c., when all the 

 mechanically suspended matters have been separated from the 

 other portion. According to very careful experiments this fluid 

 part often contains 16 per cent, of annual matters, salts, <Scc., 

 intimately or chemically combined with tlie water. 



No farmer, after such an analysis of the sewerage of a large 

 city, can feel surprised at the important results from the use of 

 that sewer water, as long practised in the vicinity of Edinburgh. 

 After learning the composition of such a foul mass — its endless 

 mixture of organic matters — its soot — its carbonate of lime — and. 



* It appears, in some extensive experiments made in Scotland, not to have 

 been successful upon arable crops ; for, to wheat, sown upon clay-land, it 

 did no good; to barley it was found injurious; potatoes were grown to a 

 large size, but were watery and unfit for the table ; and, on turnips, it was 

 found not half so efficient as mere fermented dung. — F. Burke. Quart. 

 Journ. of Agric. No. XIX, 



