10 



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 highest 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 few gen- 

 eral explanations are necessary. In each experiment the weight of 

 the entire product of eacli plot was taken, hard corn, 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 forty cents and soft corn at twenty cents 

 per bushel, and stover at $4 per ton. The bare cost only of fertil- 

 izers is taken into consideration in calculating profit or loss. No 

 account is made of the labor of applying. Nitrate of soda is esti- 

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

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

 at $5 per cord. 



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

 average of the two nearest nothings, with one or two exceptions which 

 will be especially pointed out and the reasons for the exception given. 

 Each of the nothings in these calculations has been given equal weight ;■ 

 no allowance for varying distance from the plot under comparison 

 being made. 



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) where nitrogen and phosphoric acid 

 are used is compared with the increase (or decrease) where phos- 

 phoric acid onlv 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 these four comparisons are added, the sum 

 divided by four ; and the result is considered the average increase 

 {or decrease) due to nitrogen. 



*To this statement there are two exceptions which will be explained later. 



