224 TRANSACTIONS OF THE 



the refuse near to our habitations, we are driven in the search for the 

 means of relief, to enquire into the necessities of agriculture, and to con- 

 sider the various means of applying our excrementitious matters, sus- 

 pended, or dissolved in water, as a fertilizer. 



I have examined various important examples hereinafter cited, and in 

 my own mind have established the fact, that by the application of manures 

 in the liquid form, a degree of continuous and constantly increasing fer- 

 tility may be obtained, such as has been produced by no other method. 

 Still the examination of the practice with sewer water has brought to 

 notice objections, on sanitary grounds, to the practice as sometimes pur- 

 sued near towns, on account of the offensive, and no doubt injurious, ema- 

 nations which the water emits when placed on and permitted to stand upon 

 the fields. The probable evils, I think, are assuredly much less than the 

 decomposition and discharge of the emanations within a town, from badly 

 arranged sewers, and within habitations from cesspools, ill-constructed 

 drains, or from accumulations on the surface. The emanations from irri- 

 gation with sewer water, I am sure, from experiment, is far less than the 

 usual top dressing with manure in the solid form. Any soil may be 

 manured with city sewage, and decomposing animalized manures with impu- 

 nity, and without the fear of causing fevers, agues, &c., provided it is so 

 located that the wind may have access to it. If, on the contrary, the free 

 motion of the air is prevented by trees, or other obstacles, there ague 

 abounds, and its effects may be readily discovered by the haggard appear- 

 ance of the inhabitants who are exposed to the influence of the rising pollu- 

 tion. Injurious effects upon health of the prolonged retention of excessive 

 moistui-e on a surface of vegetable mould, where the ground becomes most 

 thoroughly saturated, is established by the production of rot among sheep, 

 red water among cattle, and fever among men ; which diseases appear 

 and disappear coincident with the operations of flooding and drying. It is 

 certain that wheresoever water is laid on the land in larger quantities than 

 it can soon absorb, or where there is alternate wetting in excess, particu- 

 larly in situations protected from atmospheric influences, malaria inva- 

 riably arises. 



The fact is, that no irrigated land is safe for sheep, or cattle in the fall, 

 to graze upon, unless it has been previously thoroughly under-drained. I 

 have had my sheep affected slightly, and my cattle lamed, on such land 

 before drainage — never after. But the general conclusion as to the unsa- 

 lubrity of the common irrigations on uudralned lands, and their unfitness 

 for proximity to towns, is corroborated by the fact that in the Lombardo- 

 Venetian provinces, where there is some of the oldest, most extensive and 

 skillfully conducted irrigation in all Europe, the government has long found 

 it necessary to interfere for the protection of the health of towns. I was 

 informed by the Grand Duke, in Milan, that permanent irrigation, on un- 

 drained land, was prohibited within five miles' distance of all the towns 

 under his rule. I proposed to him a plan, which I have practiced success- 

 fully since, under many varied circumstances, in horticultural field and 



