REPORT OF THE CHEMIST. 151 



wastes must be coufiued to so limited a surface tliat it can liardly be 

 regarded as fulfillment of the law of compensation. Tons of pbosplioric 

 acid, ammonia, and potasL, in the form of flour, beef, and pork, are col- 

 lected from millions of acres and brought to our crowded cities to be 

 ultimately thrown into the sewers. I^ow, what does it avail to the fields 

 a thousand miles away that a few hundred acres in the immediate 

 vicinity of the city are rendered fertile by sewage irrigation? What is 

 needed is the separation of the fertilizing materials from the crude mass, 

 by this means reducing its bulk and weight to such dimensions that, 

 like guano, it will bear'trausportation thousands of miles. 



That portion of food-material which was originally derived from car- 

 bonic acid and water, and which constitutes about 80 per cent, of the 

 whole weight, need not be returned, as these compounds are abundantly 

 supplied everywhere. By a complete separation of water from excre- 

 ment, the weight to be transported ^ill be reduced more than four-fifths, 

 and by deodorizing the remainder it will have such a form that it can 

 be transported to any place vv here it may be needed. This is indeed the 

 desideratum, though it appears to be the point that has been most 

 overlooked in the protracted investigation to which this subject has 

 been submitted. Almost every eflbrt to dispose of the waste matter 

 constantly accumulating in cities has been in the direction of adding to 

 the bulk and weight, thus rendering transportation to any considerable 

 distance impracticable. 



To mix sewage with large volumes of water, as is done in most of our 

 cities, is not only to waste the manure, so far as the country at large is 

 concerned, but it sadly fails of its aim as a sanitary measure. In farm- 

 houses, and in villages and small towns, Ivloule's earth-closet meets the 

 requirements in a manner which admits of but little improvement. It 

 is also well adapted to the use of barracks and soldiers' quarters, to 

 asylums, hospitals, and prisons, where the care of the closets can be 

 made the duty of a special agent, and where the accumulation of excreta 

 is not too large to be used, economically, in the immediate neighbor- 

 hood; but it violates the correct principle of sewage economy by in- 

 creasing, instead of diminishing, the bulk and weight of material to be 

 trans])orted. In large cities, therefore, the introduction of the " earth- 

 closet system '' has met with difficulties which appear to be practically 

 insurmountable. The solid and liquid excrement of an adult in health 

 may be estimated at three pounds per day, or two pounds each as the 

 average of a mixed population, Now, it has been found in practice 

 that three times tiiis weight of dry earth is required to absorb the water 

 and deodorize the excrement. This would be six pounds for each indi- 

 vidual daily. A city of 100,000 inhabitants will require the preparation 

 and distribution of 000,000 pounds of dry earth every day. This 30,0iX) 

 tons of earth has not only to be distributed, but it must be collected 

 and removed with the additional weight of its absorption, amounting 

 now to an aggregate of 40,000 tons. But, worst of all, this process ha,s 

 so diluted the ijroduct and increased its weight, that its mauurial value 

 will not pay the expense of its transportation beyond the near vicinity 

 of the city, so that to the country at large it is virtually lost. Even it 

 these objections could be overcome, yet in the absence of any general 

 supervision over its use in private families, the earth-closet, in cities, 

 will evidently prove a failure. 



The limits of this paper will not permit a description of the various 

 methods which have been proposed, and, to some extent, adopted, for 

 collecting and utilizing their wastes in the various cities of the world. 

 Tlie number and variety of the methods proposed prove that, to the 



