Composition of the Manures. 139 



were supplied in the substances designated in commerce as 

 follows: Potash as sulphate of potash (and in nitrate of 

 potash). Soda as sulphate of soda (and in nitrate of soda). 

 Magnesia as sulphate of magnesia (Epsom salts). Lime 

 as sulphate (gypsum), phosphate, and " superphosphate." 

 Phosphoric acid as bone ash, mixed with sulphuric acid in 

 quantity sufficient to convert most of the insoluble phosphate 

 of lime into sulphate and soluble " superphosphate " of lime. 

 Sulphuric acid in the above phosphatic mixture, in sul- 

 phates of potash, soda, and magnesia, and in sulphate of 

 ammonia. Chlorine in " muriate of ammonia " (chloride 

 of ammonium, or sal ammoniac). Silica as silicate of soda 

 and silicate of lime (also in cut wheat straw). Other con- 

 stituents have been artifically supplied as follows : Nitrogen 

 as sulphate of ammonia, as " muriate of ammonia," and as 

 nitrate of soda. Non-nitrogenous organic matter yielding, 

 by decomposition, carbonic acid and other products in saw- 

 dust and in cut wheat straw. " Ammonia-salts," wherever 

 referred to, are equal parts of sulphate and muriate of 

 ammonia of commerce ; and " superphosphate of lime" was 

 always per acre, 2001b. bone-ash, 1501b. sulphuric acid (of 

 specific gravity 17), and water. The artificial manures 

 were mixed with ashes (burnt soil and turf) in quantity 

 sufficient to make up a convenient measure for equal dis- 

 tribution over the land, and the mixtures were sown broad- 

 cast by hand, experience having proved this to be the best 

 method on a limited area. The dressings of the plots were as 

 follows : 



Plot 1. Farmyard manure and ammonia-salts, 8 years, 

 1856-63 ; ammonia- salts only 1864, and each year since. 



Plot 2. Farmyard manure, 8 years, 1856-63 ; unmanured 

 1864, and each year since. 



Plot 3. Unmanured, every year, 1856, and since. 



Plot 4. I. Sawdust (without effect), 3 years, 1856-58 ; 

 superphosphate of lime, 1859, and each year since. 



Plot 4. II. Sawdust (without effect), 3 years, 1856-58; 



