Some Causes of Unproductiveness in Soils. 119 



tion of subsoil ploughing is commenced, for such injurious matters, 

 which it is better not to bring to the surface. 



The particulars here related afford a complete answer to those 

 who maintain that chemical analyses of soils are of no use what- 

 ever to the farmer. 



The following analysis shows the 



Composition of a Soil reclaimed from the Sea on the Hampshire Coast. 



Water 5-45 



Organic matter and water of combination ., ,. 9'93 



Oxides of iron and alumina 7'18 



Sulpliate of protoxide of iron (green vitriol) .. .. 1"39 



Bi-sulpliide of iron (iron pyrites) '78 



Sulj^liate of lime -34 



Magnesia '51 



Chloride of sodium '04 



Potash and soda '83 



Insoluble siliceous matter 73'55 



. 100-00 

 The constitution of this soil is very similar to that reclaimed 

 from the Haarlem Lake ; the remarks on the preceding analysis, 

 therefore, apply with equal force to this, which is given as an 

 example of the occurrence of land in England poisoned by green 

 vitriol. 



More recently I had an opportunity of inspecting a field near 

 Sandy in Bedfordshire, a portion of which was so completely 

 sterile, that not a weed nor a single blade of grass could be seen 

 on it. The following is its analysis : — 



Composition of a completely Barren Soil from Sandy, in Bedfordshire. 



Dried at 212=' F. 



Organic matter and water of combination .. .. 4*27 



Oxides of iron and alumina 3*84 



Phosphoric acid '09 



Sulphate of lime '85 



Magnesia -96 



Potash and soda -47 



Sulphate of iron (green vitriol) 1-05 



Sulphide of iron (iron pyrites) '50 



Insoluble siliceous matter (chiefly sand) 87'91 



100-00 

 Here again we find sulphate as well as sulphide of iron in appre- 

 ciable quantities. Tested with litmus-paper, this soil showed 

 a strong acid reaction, and [when heatecl in a platinum capsule 

 gave off pungent fumes of sulphurous acid. Soils in a healthy 

 condition, it may be remarked, when heated, do not give off 

 pungent vapours, smelling like those of a lighted sulphur match. 

 This is in itself a tolerably sure sign of the presence of injurious 

 iron compounds. 



