ROTHAMSTED FIELD EXPERIMENTS. 



( x ) Including 1 year fallow. 

 ( 2 ) 1 " wheat 



laiiow. 



wheat and 5 years fallow, 

 i-; 4 years fallow. 



(4) " 2 " " 



( 5 ) Clover, 12 times sown, 8 yielding crops, but 4 of them very small, 

 1 year wheat, 5 years barley, 12 years fallow. 



( 6 ) Including barley without manure 3 years (llth, 12th and 13th sea- 

 sons.) 



Samples of all the experimental crops are brought to the laboratory. 

 Weighed portions of each are partially dried and preserved for future 

 reference or analysis. Duplicate weighed portions of each are dried at 

 100 C., the dry matter determined, and then burnt to ash. The quantities 

 of ash are determined and recorded, the ashes themselves being pre- 

 served for reference or analysis. In a large proportion of the samples 

 the total nitrogen is determined, and in some the amount existing as 

 albuminoids, amides, and nitric acid. In selected cases, illustrating the 

 influence of season, manures, exhaustion, etc., complete ash-analyses 

 have been made, numbering in all more than 700. Also in selected cases, 

 illustrating the influence of season and manuring, quantities of the 

 experimentally grown wheat-grain have been sent to the mill, and the pro- 

 portion and composition of the different mill-products has been deter- 

 mined. In the sugar-beet, mangel-wurzel, turnips, and potatoes, the 

 sugar in the juice has, in many cases, been determined, by polariscope, 

 or by copper, or both. In the case of the experiments on the mixed 

 herbage of permanent grass-land, besides the samples taken for the 

 determination of the chemical composition (dry matter, ash, nitrogen, 

 woody fiber, fatty matter, and composition of ash), carefully averaged 

 samples have frequently been taken for the determination of the botan- 

 ical composition. 



Samples of the soils of most of the experimental plots have been 

 taken from time to time, generally to the depth of nine, eighteen, and 

 twenty-seven inches, and sometimes even to four times this depth. In 

 this way more than fifteen hundred samples have been taken, submitted 



