A large number of systematic measurements were taken by most 

 of the experimenters. These were advised with a view to the study 

 of the effects of the several fertilizers during different stages of the 

 growth of the crop. The general method of measurement was to 

 take every sixth to tenth hill (varying according to length of row) in 

 the middle row of each plot. The leaves were straightened to the 

 highest possible point, and from the tip to the ground was the height 

 recorded. The records will be found under the appropriate 

 experiments. 



Before giving a detailed account of these experiments a tew general 

 explanations are necessary. In each experiment the weight of the 

 entire product of each plot was taken, hard cor/i, soft corn, and 

 stover separately. In converting hard corn into bushels 75 pounds 

 of ears are considered equal to one bushel of shelled corn and in the 

 case of soft corn, 90 pounds. In obtaining the value of the crop, 

 hard corn is estimated at seventy-five cents and soft corn at thirty 

 cents per bushel, and stover at $5 per ton. The bare cost only of 

 fertilizers is taken into consideration in calculating profit or loss 

 No account is made of the labor of applying. Nitrate of soda is 

 estimated at $50 per ton ; Dissolved bone-black at $30 ; Muriate of 

 potash, at $40; Plaster, at $9; and Lime at $12: and barn-yard 

 manure, at $5 per cord. 



In determining gain or loss from any plot it is compared with the 

 two nearest nothings, each being given n weight inversely propor- 

 tional to its distance from the plot under comparison. 



In the determination of the effect of each of the ingredients of 

 plant-food — nitrogen, phosphoric acid and potash — four comparisons 

 are made. For example in the case of nitrogen : 



1. The crop where nitrogen alone is applied is compared with the 

 average of the two nearest nothings. 



2. The increase (or decrease) when nitrogen and pliosphoric acid 

 are used is compared with the increase {or decrease) where phospho- 

 ric acid only is used. 



3. The increase {or decrease) where nitrogen and potash are used 

 is compared with the increase {or decrease) where potash only is used. 



4. The increase {or decrease) where nitrogen, phosphoric acid 

 and potash are used is compared with the increase {or decrease) 

 where the two latter only are used. 



5. The results of the four comparisons are added, the sum divided 

 by four, and the result is considered the average increase {or decrease) 

 due to nitrogen. 



