118 SCIENCE OF AGRICULTURE. 



haps, peat meadows, possess sufficient of these to 

 supply all the inorganic matter, which plants will 

 need, for centuries to come. Salts and geine may 

 vary and must be modified and supplied by cultiva- 

 tion. These views lead to Dr. Samuel L. Dana's 

 simple and accurate mode of analysing soils — a mode 

 that at once determines the value of a soil from its 

 quantity of soluble and insoluble geine and salts of 

 lime, magnesia, &c. 



Rules of Analysis. 



1. "Sift the soil through a fine sieve. Take the 

 fine part; hake it just up to browning paper. 



2. " Boil one hundred grains of the baked soil, 

 with fifty grains of pearlashes, saleratus or carbonate 

 of soda, in four ounces of water, for half an hour; let 

 it settle ; decant the clear ; wash the ground with 

 four ounces boiling water ; throw all on a weighed 

 filter, previously dried at the same temperature as 

 was the soil; wash till colorless water returns. Mix 

 all these liquors. It is a brown colored solution of 

 all the soluble geine. All sulphats have been con- 

 verted into carbonates, and with any phosphats, are 

 on the filter. Dry therefore, that, with its contents, 

 at the same heat as before. Weigh — the loss is sol- 

 uble geine. 



3. "If you wish to examine the geine, precipitate 

 the alkaline solution with excess of lime water. The 

 geaie of lime v/ill rapidly subside, and if lime water 

 enough has been added, the nitrous liquor will be 

 colorless. Collect the geate of lime on a filter; wash 

 with a little acetic or very dilute muriatic acid, and 

 you have geine quite pure. Dry and weigh. 



4. " Replace on a funnel the filter and its 

 earthy contents; wash with two drams muriatic acid, 

 diluted with three times its bulk of cold water. 

 Wash till tasteless. The carbonate and phosphate 

 of lime will be dissolved with a little iron, which has 

 resulted from the decomposition of any salts of iron, 



