TREATMENT OF NIGHT-SOIL. 183 



up into genial heat cold and slow soil. There are other 

 materials within the easy reach of many, such as saw-dust for 

 those in the neighborhood of saw-mills: this forms a good 

 absorbent, and, as it decays in the ground, gives valuable 

 food to the plants. We have largely used spent tan in com- 

 post. This seems at first sight a very intractable material ; 

 but, in thankful remembrance of the late Professor Mapes, 

 we would suggest a mode taught by him which soon converts 

 and subdues this stubborn material into practicable use : it 

 is simply composting the material with a salt-and-lime mix- 

 ture. The process is simple, and may be thus described: 

 suspend in a cask of water a basket of rock-salt, facilitate its 

 solution by daily stirring, and, when the water has taken up 

 all the salt it can hold in solution, then use it in slacking 

 quick-lime : the product is a chloride of lime, which, when 

 composted with the spent tan, soon converts it into a shape 

 fit to be used as a fertilizer, and into material which could be 

 most advantageously used in combination with night-soil. 

 While the night-soil lay in the cistern, the spent tan could be 

 undercfoinff the salt-and-lime treatment. The refuse bone- 

 black of the sugar refineries has been largely recommended 

 by authors ; but this material has such a glazed and hardened 

 surface, that it requires treatment with sulphuric or muriatic 

 acid to render it convertible, and in addition, though it was 

 formerly a material gladly given away by the refineries, it has, 

 since the manufacture of phosphate of lime in this country, 

 become an article of commercial value, alike with the bones 

 of animals. 



Thus much for the mode of treatment, and rendering avail- 

 able for agricultural use, this much neglected fertilizer. We 

 have spoken of its value as furnishing all the elements for a 

 crop, of the labor saved over the proper care and distribution 

 of barnyard-manure. As an article of commercial value, 

 hear once more the words of the learned Liebig : " The 

 importation of urine or of solid excrements from a foreign 

 land is quite equivalent to the importation of corn and 

 cattle. All these matters in a certain time assume the form 

 of corn, flesh, and bones : they pass into the bodies of men, 

 and again assume the same form which they originally pos- 

 sessed." 



Lastly, We have spoken of the connection between the 



