SOILS, CHEMICAL ANALYSIS. 477 SOILS, COMPOSITION OF. 



necessary details in a manner which any 

 intelligent reader may easily follow. 



Rough Methods of Determining Cha- 

 racter of Soils. The chemical analysis of 

 soils, as it has been inferred, and as it may 

 be seen by any one who will refer to a 

 tabulated statement of the results of an 

 analysis, is manifestly an operation which 

 requires professional knowledge and great 

 care, skill, and nicety in its management. 

 Few persons, perhaps, whether gardeners 

 or amateurs, will take the trouble to 

 attempt and carry out anything of this 

 kind in the regular way, and for the 

 information of such as these it is desirable 

 to point out some simple means by which 

 the natural properties of the different kinds 

 of soils, and the presence of their chief and 

 most important constituents, may be ascer- 

 tained roughly, though not with any de- 

 gree of precision or even approximately. 

 Thus: 



(a) If there be clay in any soil, the 

 tenacity of the soil will indicate its pre- 

 sence. 



(b) If there be calcareous matter, or lime 

 *r chalk, in any soil, its presence may be 

 detected by pouring muriatic acid on it. 

 If effervescence takes place freely the soil 

 thus tested is calcareous. Soils of this 

 character, as well as clays, marls, and 

 loams, are soft to the touch. Loudon 

 says : "To ascertain the quantity of cal- 

 careous earth present, dry soil thoroughly, 

 and weigh a hundred grains of it, which 

 gradually add to one drachm of muriatic 

 acid, diluted with two drachms of water in 

 a phial poised in a balance ; the loss of 

 weight will indicate the escape of carbonic 

 acid, which will be 44 per cent, of the 

 quantity of calcareous earth in the soil." 



(c) If there be sand in any soil, the soil 

 will feel rough and harsh to the touch, and 

 if a little of it be rubbed on a piece of 

 glass, the glass will be scratched. 



(a) If the soil be marly or loamy , it will 



feel unctuous or greasy to the touch when 

 rubbed between the finger and thumb. 



(e) If the soil contain humus, or, in 

 other words, decomposed organic matter, 

 whether vegetable or animal, its presence 

 may be ascertained by drying a portion ol 

 the soil thoroughly, and then, after weigh- 

 ing it, subjecting the soil so dried to a red 

 heat. When withdrawn it must be weighed 

 again, and the difference between its pre- 

 sent weight and its weight before heating 

 will show the proportion of organic matter 

 in the soil. 



(/) If there be iron in any soil that is 

 to say, oxide of iron its presence will im- 

 part a reddish or yellowish colour, and 

 sometimes even a greenish colour, to the 

 soil. 



(g) If there be salt in any soil, its pre- 

 sence will be shown by its saline taste, as 

 well as by whitish effervescence or incrus- 

 tation on the surface. 



Soils, Composition of. 



The chemist will tell you that soils are 

 compounded of a great many chemical 

 substances, and that there are about four- 

 teen constituents, which are present in 

 varying proportions in all fertile soils. 

 The practical cultivator, however, will tell 

 you that there are some five or six well- 

 ascertained varieties of soil, characterised 

 according to the preponderating propor- 

 tions of silica, lime, clay, vegetable mould, 

 marl, or loam, which they contain, accor- 

 ding to his rough estimate. 



(a) Sandy soils contain 80 per cent., 

 or thereabouts, of silica that is, of the 

 crumbling debris of granite or sandstone 

 rock. 



(b) Calcareous soils contain upwards of 

 20 per cent, or lime in their composition. 



(c ) Clay soils contain 50 per cent, of stifi 

 unctuous clay. 



(d) Peaty soils or vegetable mould, the 

 richest of all garden soils, contains from 



