184 



On the Physical Properties of Soil, 



of a cubic inch of the same in its wet state 605 grains ; since 100 

 grains of this sand absorb 25 parts^ the 605 grains^ which form 

 the cubic inch^ will in like manner absorb 121 grains. 



The following Table contains the results of the experiments 

 which I made^ in reference to this branch of the subject^ with 

 such soils as usually come under the notice of the agriculturist. 

 I add^ at the same time, to the list of these soils, the finely pre- 

 pared carbonate of lime, obtained by precipitation from solutions 

 in acids, and also pipe-clay, as representing one of the purest and 

 finest of the clays : — - 





Power of containing 



A cubic inch contains in 



A cubic foot 





water. 



the w et state 



of the 



jxincis 01 Jiartn4 











wet earth 



According 



According 



Grains of 



Cubic lines 



contains of 

 water 





to weight. 



to volume. 



water. 



of water. 





Per cent. 



Per cent. 







Pounds. 



Siliceous sand . • . . 



25 



37.9 



121 



655 



27.3 



Calcareous sand . . . 



29 



44.1 



141 



763 



31.8 



Gypsum powder , , 



27 



38.2 



122 



660 



27.4 



Lime, precipitated . . 



47 



54.5 



174 



941 



39.1 





85 



66.1 



211 



1142 



47.5 



Fine magnesia . • . . 



256 



76.1 



242 



1316 



62.6 





40 



51.4 



164 



888 



38.8 



Loamy clay • • . . 



50 



57.3 



183 



991 



41.4 



Stiff clay, or brick earth . 



61 



62.9 



201 



1088 



45.4 



Pure grey clay . • • . 



70 



66.2 



212 



1145 



48.3 



White clay, pipe-clay , . 



87 



66.0 



211 



1142 



47.4 





181 



69.8 



223 



1207 



50.1 



Garden-mould .... 



89 



67.3 



215 



1164 



48.4 





52 



57.3 



181 



980 



40.8 





34 



49.9 



158 



863 



35.6 



From this Table we obtain the following general results : — 



1. The sands have the smallest power of containing water, 

 whether they are compared in weight or in volume with the other 

 earths : siliceous sand has the least power of them all ; the sands 

 themselves, moreover, differ according to the different fineness of 

 their grains ; with large-grained sand the power becomes dimi- 

 nished down to 20 per cent., while it amounts to 40 per cent, 

 when the particles are exceedingly fine. 



2. Gypsum powder very nearly approaches the sands in this 

 respect, and possesses even a somewhat smaller power of contain- 

 ing water than calcareous sand. 



3. Slaty marl, notwithstanding the great proportion of clay it 

 has already been remarked to contain, exhibits only a small power 

 of containing water, and in this respect most nearly resembles 

 sand of all the usual constituents of soil ; and having this quality, 

 it must be particularly calculated to render the soil both warmer 

 and dryer : these kinds of marl are accordingly frequently ap- 

 plied in the south-west parts of Germany to the improvement of 

 vineyards. 



