ON THE ESSENTIAL CONSTITUENTS OF MANURES. 35 



Moisture when analysed 4*72 



Organic matter and water of combination 11*03 



Oxides of iron 9*98 



Alumina 6*06 



Carbonate of lime s 12*10 



Sulphate of lime *75 



Alkalies and magnesia (determined by loss) 1*43 



Silica (soluble in dilute caustic potash) 17*93 



Insoluble siliceous matter (chiefly clay) 36*00 



100*00 



The experimental field was well drained. The surface soil is thin, poor, 

 and full of fragments of limestone, which render the land lighter. Separated 

 from the stones, the soil may be regarded as a stiffish clay-marl, which in wet 

 weather is very tenacious and heavy, and in warm weather dries into hard 

 unmanageable lumps. The depth of the soil was inconsiderable. 



The twelve experimental plots were treated in regard to manure as fol- 

 lows : 



At the rate 

 of per acre. 



To Plot 1 was applied well-rotten farmyard manure 15 tons. 



To Plot 2 was applied gypsum 6 cwt. 



To Plot 3 was applied bone-ash dissolved in sulphuric acid .... 6 cwt. 



To Plot 4 was applied sulphate of ammonia 6 cwt. 



To Plot 5 was applied bone-ash dissolved in sulphuric acid 6 cwt. 



and sulphate of ammonia 6 cwt. 12 cwt 



To Plot 6 was applied bone-ash dissolved in sulphuric acid . . , . 12 cwt. 



To Plot 7 was applied sulphate of potash 6 cwt. 



Plot 8 (unmanured). 



To Plot 9 was applied crystallized sulphate of soda 12 cwt. 



To Plot 10 was applied bone-ash dissolved in acid 6 cwt. 



sulphate of potash 6 cwt. 



sulphate of ammonia 6 cwt. 18 cwt. 



To Plot 11 was applied bone-ash dissolved in acid 3 cwt. 



Plot 12 (unmanured). 



The dissolved bone-ash on analysis yielded the following results : 



Water 32*80 



Organic matter *13 



Biphosphate of lime (CaO, PO 5 ) 18*49 



Equal to bone-earth rendered soluble by acid . . (28*80) 



Insoluble phosphates 6*43 



Hydrated sulphate of lime 38*39 



Alkaline salts 1*94 



Sand 1*82 



100*00 



This preparation thus contained a large per-centage of soluble phosphate 

 as well as gypsum, which necessarily must be formed when bone-ash is dis- 

 solved in acid. It having been stated by a high authority that in Messrs. 

 Lawes and Gilbert's turnip experiments the sulphate of lime contained in their 

 superphosphate might have had quite as much influence upon the produce 

 as the phosphate of lime, it appeared to me desirable to apply gypsum alone 

 to one plot. Turnips contain a considerable quantity of sulphur ; it is there- 

 fore not unlikely that in soils deficient in sulphate of lime, the artificial sup- 

 ply of sulphates may be found advantageous to the turnip crop. At the same 



D2 



