M. De Gasparin on the Classification of Soils. 93 



SECOND CLASS.— SILICEOUS SOILS. 



Characters. — Producing no effervescence with acids ; affording by le- 

 vigation at least 0.70 for tlieir premier lot,* 



THIRD CLASS.—CLAYS. 



Characters. — Not yielding effervescence ■with acids, and affording bj' 

 levigation less than 0.70 of the first portion. 



FOURTH CLASS— CALCAREOUS AND MAGNESIAN SOILS. 



Characters. — Producing effervescence with acids ; lime, or magnesia, 

 or both, are found in the solution. 



First Sub-Ordbr Chalks. 



Characters. — Leaving no residue after the action of the acid, or only 

 leaving a siliceous residue less than 0.50. 



Second Sub-Ordkr Sands, 



Character. — This soil contains at least 0.50 part of siliceous or calca- 

 reous sand, which does not escape from a sieve whose division or holes 

 are the 0.02 of an English inch in diameter. 



Third Sub-Order — Clavs. 

 Character. — This soil leaves a residue of 0.50 of clay after effervescence 

 and levigation. 



Fourth Sub-Ordkr. — Marls. 

 Character. — After the action of acid, a clay remains wliose levigation 

 does not remove more than 0.10 of free silex. 



First Section Calcareous Marls. 



Character. — Having at least 0.60 of carbonate of lime or magnesia in 

 their composition. 



Second Section. — Argillaceous Marls. 

 Character. — Having at least 0.50 of clay. 



Fifth Slb-Obder Loams. 



Character. — After the action of acid, the residuum presents clay and 

 free silica, which, by their levigation, give each more than 0.10 of the 

 weight of the soil. 



SECOND DIVISION.— SOILS WITH AN ORGANIC BASE. 

 Character. — Losing at least a fiftieth of their weight when they are 

 heated till they do not emit more vapour. 



FIRST CLASS.— FRESH MOULD. 



Character. — The water in which this mould is digested or boiled does 

 not redden litmus paper. 



* The "premier lot" comprehends the large particles which are deposited 

 when the water in whicli the earth is dissolved, is strongly shaken. 



