514 On the Growth of Barley hy different Manures, Sfc. 



and partly in 1846, and the increase of produce taken over the 

 three years (1844, 1845, and 1846) — and of about 15 parts of 

 nitrogen in the form of guano applied only in 1844, and the 

 increase taken over 1844, 1845, and 1846 — are utterly incom- 

 parable with one another on the point here in question. 



It should be mentioned with regard to the inferior result of a 

 given amount of nitrogen as sal-ammoniac and phosphates, when 

 compared with that in the form of guano, that Kuhlmann particu- 

 larly stated that his crop by the former was in the first year (both 

 hay and aftermath) so over-luxuriant from excess of manure, that 

 it was necessarily cut before the proper time to prevent its rotting 

 at the bottom. 



With regard fo the guano again, Kuhlmann states it to have 

 contained 4*98 per cent, of nitrogen ; but from the form of state- 

 ment it does not seem clear whether this estimate was founded 

 upon the analysis of the particular sample employed. As it is 

 described as Peruvian guano, and also on account of the result, 

 it is pi'obable that the amount of nitrogen supplied in the guano 

 was considerably greater than that assumed. After throwing out 

 this observation, we, of course, take the results as apparently 

 intended by M. Kuhlmann, and as quoted by Baron Liebig. But 

 Kuhlmann gives two experiments, side by side, with the very same 

 guano. The one supplied, according to his estimate, in round 

 numbers, 15 parts of nitrogen to a given area, and the other 30 

 parts ; but it is the result of the smaller amount only (15 parts), 

 which Baron Liebig cites to compare with the 176 parts in the 

 sal-ammoniac with phosphates. The comparison of the effects 

 of a given amount of nitrogen in guano, used in the single and 

 in the double quantity to a given area, is as follows : — 



Nitrogen in M nure. 



100 parts in the form of Guano, -when 300 * parts of it 

 were employed 



100 parts in the form of Guano, when 600 * parts of it 

 ■were employed 



Yielded Increase of 

 Produce. 



16,400 parts of Hay. 

 9,566 „ „ 



Here then, a given amount of nitrogen in the form of combi- 

 nation and admixture of the very same guano, its action being 

 taken over exactly the same seasons, gave 72 per cent, more 

 increase when used in the smaller than in the larger quantity. 

 1 et it is the action of the smaller cjuantity applied in one year, 

 and acting over three, which Baron Liebig selects to contrast 

 with the large amount of nitrogen applied in different seasons in 



* For the convenience of round numbers we, with Baron Liebig, have assumed 

 the guano to contain 5 per cent, of nitrogen instead of 4*98 per cent, as given by 

 Kuhlmann. 



