Analysis of Soils. 405 



passed through the muslin must now be boiled in a small tea- 

 cup full of clean water, for about five minutes ; being allowed to 

 cool, and a piece of clean blotting paper, previously dried 

 before the fire and its weight ascertained, employed to strain 

 the liquor through, care must be taken to get every particle of 

 the soil into the strainer from the vessel in which it was 

 boiled, by repeated washings with clean water. When the 

 liquor is all strained away, place the blotting paper on a plate 

 over the candle, with a shaving of deal on the plate, and dry it 

 until the shaving begins to scorch. When perfectly dry, weigh 

 the whole ; and then, the weight of the paper being subtracted, 

 the weight of the residue, and, consequently, the quantity of 

 matter dissolved by the water, will be afforded ; this, which 

 consists of salts and vegetable extract, we will suppose, amounts 

 to 4^ grains. The watery solution must be carefully set on 

 one side, and the analysis of the solid parts proceeded with. 

 Half an ounce, by measure, of muriatic acid (spirit of salt) 

 must be poured upon this in a saucer, and allowed to remain 

 for full an hour, being occasionally stirred with a piece of 

 glass or porcelain; this must now be strained by means of a 

 piece of blotting paper as before, the matter left upon it 

 being frequently washed with clean water, and the washings 

 allowed to pass through the paper to mingle with the other 

 acid liquor; the matter left upon the paper being perfectly 

 dried and weighed, and the loss ascertained, we will suppose 

 this to be 20 grains. Into the liquor must be dropped, gra- 

 dually, a solution of prussiate of iron. The blue precipitate 

 which this will occasion, being collected by filtering through 

 paper, and washed as before, heated red-hot by means of an 

 iron spoon in the fire, and then weighed, we will suppose it 

 to weigh 2J grains ; this is oxide of iron. This deducted 

 from the 20 previously ascertained to be in the solution, leaves 

 17^ grains, which may be considered as carbonate of lime 

 (chalk), though probably with the admixture of a little car- 

 bonate of magnesia. The solid matter must now be heated to 

 redness in a spoon, until upon cooling it does not appear at 

 all black ; this must then be weighed, and the loss noted ; 

 that loss consisted of animal and vegetable matters, we will 

 suppose it amounted to 7 grains. The remainder must be 

 boiled for about two hours with 2 drachms, by measure, of 

 sulphuric acid, mixed with 8 drachms of water, and, when 

 cooled, strained through blotting paper as before and washed; 

 when dried at a red heat in the iron spoon, the loss sustained 

 will be alumina (clay) ; what remains will be silica (flint). 

 We^will suppose the first to weigh 15 grains, and the latter 

 102^ grains. 



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