AnsonitENT r(»A\ Eu of soils. 175 



the absorbent ; and in others, as where mordants are used, 

 chemical combinations supervene, which possess extraordi- 

 nary stability. 



Many facts are known which show that soils, or certain 

 of their ingrcdionts, have a fixing power like that of char- 

 coal and textile fibers. It is a matter of common expe- 

 rience that a few feet or yards of soil intervening between 

 a cess-pool or dung-pit, and a well, preserves tlie latter 

 against contamination for a longer or shorter period. 



J. P. Bronner, of Baden, in a treatise on " Grape Cul- 

 ture in South Germany," published in 1836, fiist mentions 

 tliat dung liquor is deodorized, decolorized, and rendered 

 nearly tasteless by filtration through garden earth, Mr. 

 Huxtable, of England, made the same observation in 1848, 

 and Prof Way and olliers have published extended in- 

 vestigations on this extremely important subject. 



Prof Way informs us that he filled a long tube to the 

 depth of 18 inches Avith Mr. Huxtable's light soil, mixed 

 with its own bulk of white sand. " Upon this filter-bed 

 a quantity of highly ofiensive stinking tank water was 

 ])Oured. The liquid did not pass for several hours, but 

 ultimately more than 1 ounce of it passed quite clear, free 

 from smell or taste, except a peculiar earthy smell and 

 taste derived from the soil." Similar results were obtain- 

 ed by acting upon putrid human urine, upon the stinking 

 water in which flax hail been steeped, and upon the water 

 of a London sewer. 



Prof. Way found that these elFects were not strikingly 

 manifested by pure sand, but appeared when cl.iy Avas 

 used. lie found that solulions of coloring matters, such 

 as logwood, sandal- wood, cochineal, litmus, etc., Avhen fil- 

 tered through or shaken up with a portion of clay, are 

 entirely d(^prived of color. {Jo>n: Hoy. Ag. Soc. of 

 Eng., XI, p. 364.) 



These efibcts of clay or clayey matters, like the fixing 

 power of cotton ami woolen stulFs upon pigments, must 



