15.2 AGBICULTURAL REPORT. 



present date, no plan has been adopted wliicli fully meets the rcquh^e- 

 meuts of tbe case. But while this is true, it is also true that in discov- 

 ering the defects of these various systems and plans we have made 

 progress in the direction of the ultimate end to be accomplished, to wit: 

 the complete removal of all waste matter from cities without nuisance 

 or annoyance to the inhabitants, and the separation therefrom of all 

 extraneous substances, leaving only the essential elements of plant-food 

 to bear the expense of transportation. 



The Chinese method of collecting and transporting the excrement 

 './fa city through its streets, in open vessels, will so offend our ideas of 

 delicacy as to forbid its adoption in any of the cities of our country at 

 least. The first and perhaps the most diiMcult problem to be solved in 

 this relation is, the removal of a large bulk of material, naturally of- 

 fensive, without disgust to the more refined sensibility of our civiliza- 

 tion. To accomplish this object, some arrangement embracing Captain 

 Liernur's i)neumatic system of collecting night-soil will, perhaps, be 

 found best adapted. At least, some mode of collection by means of ex- 

 hausted reservoirs, and conveyance through the streets in air-tight 

 vessels, must be adoi)ted to accommodate our American ideas of decency. 

 Collections must be made frequently, and in warm weather daily, or 

 chemical agents must be used to prevent fermentation. This will be ne- 

 cessary, not only for the health and comfort of the inhabitants, but also 

 to secure the full value of the material collected. The tendency of nitro- 

 gen, phosphorus, and sulphur to combine with hydrogen, forming vola- 

 tile compounds which readily escape into the air and are lost, is a mat- 

 ter demanding more attention than has hitherto been given to it. 

 Human excrement, on an average, contains the elements of about 20 per 

 cent, of ammonia, after deducting the water ; but if that ammonia is 

 formed in exposure to the air and without chemical provisions to retain 

 it, less than one-fourth of that amount will be available. It is from this 

 cause, chiefly, that the statements of scientific men, as well as of practi- 

 cal farmers, on the subject of the manurial value of excrement, are so 

 varied and condradictory. One makes his examinations of the article in 

 its fresh state j another, after it has undergone fermentation, and the 

 volatile compounds have escaped ; and hence the discrepancy. 



In the second place, some method must be devised to separate the water, 

 amounting to about 90 per cent., with which the valuable material is 

 mixed. It is at this point that Liernur's pneumatic system fails to meet 

 the requirements in disposing of sewage. It proposes, after collectingthe 

 contents of cesspools and vaults, to transport the whole, in its crude state, 

 to the fields where it is to be used as a manure. The 90 per cent, of water 

 which he thus transports at great expense is of no more value than that 

 which flows in the river or descends from the clouds. Means must be 

 devised for the separation of this water, that the remaining 10 per cent, 

 of really valuable material may be so reduced in volume and weight, 

 and so changed in form, as to bear transportation to any place where it 

 may be most in demand. It has been proposed to effect this object by 

 precipitation, but there are chemical obstacles in the way which, in the 

 present state of our knowledge, appear to be insurmountable. Evapo- 

 ration presents itself as the only practical method of accomplishing this 

 object. Before evaporation is attempted, it will be necessary to convert 

 the ammonia which may be present into a sulphate, a chloride, or some 

 other form that will be involatile at the temperature employed for evap- 

 oration. To the method of desiccation by solar heat there is the objec- 

 tion of the intolerable nuisance produced by the escape of the fetid 

 compounds of sulphur and i)hosi)horous with hydrogen. Desiccation 



