AMYLACEOUS. 



difficult solubility (1 part of gypsum requires 

 400 parts of water for solution), and also to 

 assist in the absorption of the sulphate of am- 

 monia by the plants; hence it happens, that 

 the influence of gypsum is not observable on 

 dry fields and meadows. 



"The decomposition of gypsum by carbonate 

 of ammonia does not take place instantane- 

 ously ; on the contrary, it proceeds very gradu- 

 ally, and this explains why the action of the 

 gypsum lasts for several years." (Org. Chem.}] 



AMYLACEOUS. A term applied to such 

 farinaceous seeds, grains, and roots, as contain 

 much of the fine flour from which starch is 

 made, and in which chiefly consists their nu- 

 tritive principle. 



ANALYSIS (Gr.<Wxw/c). In a general sense, 

 signifies the resolution of compound bodies 

 into their original or constituent principles. 



AnafyfiiOfSoUi, The means of ascertain- 

 ing the nature, properties, and proportions of 

 the different materials of which they are com- 

 The chemical examination of the soil 

 affords perhaps more certain and more valua- 

 ble information to the farmer, for the improve- 

 ment of its fertility, than any other mode of 

 ation. The apparatus and the experi- 

 ments, necessary for even the most accurate 

 experiments, are by no means so difficult as it 

 is often believed is the case. It is, in fact, a 

 very erroneous conclusion, that an extensive 

 or an expensive apparatus is necessary t<> 

 carry on even the most valuable chemical 

 researches. The laboratory of one of the most 

 celebrated chemical philosophers of his day, 

 that of Dalton of Manchester, contained appa- 

 rently but a poor collection of glass bottles, re- 

 " i Mes. fragments of wine-glasses, &c. 



The following descriptions of the philoso- 

 phically-accurate mode adopted by Sir Hum- 

 1 ivy for the analysis of soils, [and of 

 the more easily repeated plans of the Rev. W. 

 Khnm, of England, and Dr. Dana, of Massa- 

 . are u'iven nearly in their own words. 

 The first is taken from his Elements of Agri- 

 cultural Chnnistry t the second from the first 

 volume of the Journal of the Royal Agricul- 

 tural Society of England, p. 46, and the last 

 from Pro/mar Hitchcock's Report of the Geologi- 

 cal Survey of Massachusetts.] It may be well 

 to premise that four earths are almost always 

 the chief constituents of all cultivated soils, 

 viz., silica (flint), alumina (clay), carbonate 

 of lime (chalk), and carbonate of magnesia. 

 These are mixed together in an endless variety 

 of proportions, and are interspersed with ani- 

 mal and vegetable remains, salts, &c., to an 

 equally varying extent. It is to ascertain the 

 presence and the extent of these substances 

 that the analysis of soils is so necessary and 

 so valuable to the farmer. 



"The instruments required for the analysis 

 of soils," said the illustrious Davy, "are few 

 and but little expensive. They are a balance 

 capable of containing a quarter of a pound of 

 common soil, and capable of turning when 

 loaded with a grain ; a set of weights from a 

 quarter of a pound troy to a grain ; a wire 

 sieve sufficiently coarse to admit a mustard- 

 seed through its apertures ; an Argand lamp 

 and stand ; some glass bottles ; Hessian cruci- 



ANALYSIS. 



bles ; porcelain or queen's ware evaporalin** 

 basins; a Wedgewood pestle and mortar; 

 | some filters made of half a sheet of blotting- 

 paper, folded so as to contain a pint of liquid, 

 and greased at the edges ; a bone knife, and 

 an apparatus for collecting and measuring 

 aeriform fluids. 



" The chemical substances or r,e-agents re- 

 quired for separating the constituent parts of 

 the soil are muriatic acid (spirit of salt), sul- 

 phuric acid (oil of vitriol), pure volatile 

 (ammonia), dissolved in water, solution of 

 prussiate of potash and iron, succinate of am- 

 monia, soap-lye, or solution of potassa, solu- 

 tions of carbonate of ammonia, of muriate of 

 ammonia, of neutral carbonate of potash, and 

 nitrate of ammonia. 



"In cases when the general nature of the 

 soil of a field is to be ascertained, specimens 

 of it should be taken from different places, two 

 or three inches below the surface, and exa' 

 mined as to the similarity of their properties. It 

 sometimes happens that upon plains the whole 

 of the upper stratum of the land is of the same 

 kind, and in this case one analysis will be suffi- 

 cient; but in valleys, and near the beds ol 

 rivers, there are very great differences ; and it 

 now and then occurs that one part of a field is 

 calcareous, and another part silicious, and in 

 this case, and in analogous cases, the portions 

 different from each other should be separately 

 submitted to experiment." 



Soils, when collected, if they cannot be im- 

 mediately examined, should be preserved in 

 phials quite filled with them, and closed Avim 

 ground glass stoppers. The quantity of soil 

 most convenient for a perfect analysis is from 

 two to four hundred grains. It should be col- 

 lected in dry weather, and exposed to the at- 

 mosphere till it becomes dry to the touch. 



The specific gravity of a soil, or the relation 

 of its weight to that of water, may be ascer- 

 tained by introducing into a phial, which will 

 contain a known quantity of water, equai 

 quantities of water and of soil, and this 

 may be easily done by pouring in water till it 

 is half full, and then adding the soil till the 

 fluid rises to the mouth ; the difference between 

 the weight of the soil and that of the water 

 will give the result. Thus if the bottle con- 

 tains 400 grains of water, and gains 200 

 grains when half filled with water and half 

 with soil, the specific gravity of the soil will 

 be 2% that is, will be twice as heavy as water; 

 and if it gained 165 grains, its specific gravity 

 would be 1 825-, water being 1000-. It is of im- 

 portance that the specific gravity of a soil 

 should be known, as it affords an indication of 

 the quantity of animal and vegetable matter it 

 contains ; these substances being always most 

 abundant in the lighter soils. 



The other physical properties of soils should 

 likewise be examined before the analysis is 

 made, as they denote to a certain extent their 

 composition, and serve as guides in directing 

 the experiments. Thus silicious soils are 

 generally rough to the touch, and scratch glass 

 when rubbed upon it ; ferruginous soils are of 

 a red or yellow colour, and calcareous soils ar 

 soft. 



1. Soils, though as dry as they can be 



83 



