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the inhabitants of Greenwich, Woolwich, Gravesend, &c. 
would suffer most severely. 5th. That the air confined in the 
new mains would seriously increase the already enormous 
volume of putrid gases in the sewers, and which was already 
so great a nuisance. 6th. That the system as well as that 
which it was to supplement, could not be considered otherwise 
than as very filthy; inasmuch, as instead of removing the 
sewage to the soil, which is the natural deodorizer, it wonld 
cause its accumulation in the bed of the river at only a 
few miles distance. 
The above were some of the principal reasons why the 
Author believed that the plan of the Board of Works would 
fail to promote the object for w'hich that which ought to have 
been the primary consideration had been neglected. He 
would now endeavour to show the practicability of utilizing 
sewage, and at the same time of cleansing large towns. In 
the first place, however, it was desirable to reiterate the 
scientific facts, which proved not only the importance but the 
absolute necessity of putting a stop to the present waste. 
Liebig states that, “ In the solid and liquid excrements of 
man, and of animals, we restore to our fields the ashes of the 
plants which served to nourish these animals. These ashes 
consist of certain soluble salts and insoluble earths, which a 
fertile soil must yield, for they are indispensable to the 
growth of cultivated plants. It cannot admit of a doubt, 
that by introducing these excrements to the soil, we give to 
it the power of affording food to a new crop, or, in other 
words, we reinstate the equilibrium which has been disturbed. 
Now that we know that the constituents of the food pass over 
into the urine and excrements of the animal fed upon it, we 
can with great ease determine the value of various kinds of 
manure. The solid and liquid excrements of an animal are 
of the highest value as manure for those plants which 
furnished food to the animal.” 
