1 10 LESSONS IN CHEMISTRY. 



considerable part of the year, is of a less nourishing description. 

 In Flanders, night-soil and urine have long been regarded 

 as the most valuable manures ; and their careful preservation 

 is an important feature in the husbandry of that country. 

 By the Belgian farmer, the value of the liquid and soUd 

 excrements of an individual, is estimated at £1 17*. per 

 annum,* and so carefully is every trace of these manures 

 collected in the towns, that the public authorities are reheved 

 from all the expense and trouble which, in this and other 

 countries, are incurred in the removal of nuisances. In China, 

 also, which has preceded us in so many of our boasted im- 

 provements, strict laws are enacted for the careful preserva- 

 tion of human excrements, and in every house, and along the 

 highways, vessels are placed for receiving them. Travellers 

 inform us, that they mix the night soil with clay so as to 

 form it into cakes which are called taffo^ and are exposed for 

 sale in all the cities of the celestial empire. 



157. Preservation of human excrements^ and methods of 

 applying them to the soil. — On the continent, where attention 

 has long been properly directed to the subject, various plans 

 have been adopted for the preservation of these manures. In 

 Flanders, the farmers not merely carefully collect the excre- 

 ments of their own neighbourhood, but purchase the contents 

 of the cess-pools in the towns, and store them in tanks of suf- 

 ficient capacity to contain all the manure accumulated during 

 several months. They apply them in the liquid state — usu- 

 ally after the sowing has been completed, by conveying them 

 from the pits, in casks, and distributing them over the fields. 



158. In Paris a different plan is adopted. The contents 

 of all the cess-pools of the city are taken away by night, to a 

 place in the suburbs, where they are deposited in an immense, 

 shallow tank, where they are allowed for some time to remain ; 

 and, when the solid matters have fallen down, the liquid is 

 made to run into a second tank, at a lower elevation, and 

 again from it into a third basin, from which the cleai* liquid 



* If we suppose, according to the calculation of Liebig, that the 

 solid matter contained in the urme of an individual annually amounts 

 to 6 7 lbs of equal fertilizing value to genuine Peruvian guano; then if 

 all the urine of a town like Belfast containing 100,000 inhabitants, was 

 collected and applied to the soil, our fields would receive the enormous 

 quantity of six million seven hundred thousand pounds, or nearly 3,000 

 tons of manure, which, at the ordinary selling price of guano, would 

 be worth thirty thousand pounds. 



