odor, by burying them for a few days in the earth. The 

 Indians of this country arc said to sweeten the carcass of 

 the skunk by the same process, when needful, to fit it for 

 their food. Dogs and foxes bury bones and meat in the 

 ground, and afterward exhume them in a state of com- 

 parative freedom fi-om offensive odor. 



When human excrements are covered with fine dry 

 earth, as in the " Earth Closet " system, all odor is at once 

 suppressed and never reajipears. At the most, besides an 

 "eartliy" smell, an odor of ammonia appears, resulting 

 from decomi)osition, which appears to ])roc-eed at once to 

 its ultimate results without admitting of the formation of 

 any intermediate offensive compounds. 



Dr. Angus Smith, having frequently observed the pres- 

 ence of nitrates in the water of shallow town wells, sus- 

 pected that the nitiic acid was derived from animal mat- 

 ters, and to test this view, made experiments on the action 

 of filters of sand, and other porous bodies, upon solutions 

 of different animal and vegetable matters. He found 

 that in such circumstances oxidation ti)ok place most rap- 

 idly — the nitrogen of organic matters being converted in' 

 to nitric acid, the carbon and hydrogen combining with 

 oxygen at the same time. Thus a solution of yeast, which 

 contained no nitric acid, after being passed through a 

 filter of sand, gave abundant evidence of salts of this acid. 

 Colored solutions were in this way more or less decolor 

 ized. Water, rendered brown by peaty matter, was found 

 to be purified by filtration through sand.* 



POWER OF SOILS TO REMOVE DISSOLVED SOLIDS FROM 

 THEIR SOLUTIONS. 



Action of Sand upon Saline Solutions. — It has long 

 been known that simple s<ind is capable of partially re- 



* This account of Dr. Smith's experiments is quoted from Prof. Way's paper 

 "On the Power of Soils to Al)sorb Manure." (Jour. Hoy. Ag. Soc. of England, 

 XI, p. 317.) 



