FERTILIZING VALUE CF VARIOUS ANIMAL MANURES. 455 



substance in its ordinary state of dryness, which will be necessary to 

 produce the same effect as 100 lbs. of common farm-yard manure, 

 supposing this effect to be determined by the nitrogen alone. 



Equal effecls 

 Water per cent. Ash per cent. Nitrogen per cent, produced by 



Farm-yard manure.. 80 ? ^ 100 lbs. 



Flesh 77 1 3§ 14 



Fish 80 2 2i 20 



Blood 79to83 1 3 16 



Blood dried* 12 to 20 3i 12 to 13 8 



Skin 58 i 8 12 



Wool, hair, and horn. 9 to 11 1 to 2 16 6 



Bones 14 40 to 60 5 to 9 11 to 20 



Refuse charcoal of 



the Sugar-works.. 48 11 50 



Animalized carbon. . 45 ? 1 50 



I have already had occasion to remark, however, that this mode of 

 classifying manures is not altogether to be depended upon. Since — 



1°. It does not take into account the quantity of inorganic matter 

 they severally contain, which as shewn in the third column is parti- 

 cularly large in bones, and is by some considered as the (most ?) im- 

 portant and influential constituent of this manure. Nor is any effect 

 ascribed to such substances as the sulphur, which in hair and wool 

 forms nearly 5 per cent, of their whole weight, and which cannot be 

 wholly without influence upon the plants, by which, as they decay, 

 the elements of these manures fhay happen to be absorbed. 



2\ It passes by the practical influence of the quantity of water 

 which the several substances contain. Flesh, fish, blood, and skin, in 

 their recent state, contain so much water that they begin almost im- 

 mediately to decompose, and thus expend most of their fertilizing 

 virtue upon the first crop to which they are applied. Hair and wool, on 

 the other hand, retain so little water that they decay^iih great slo w^ss. 

 Hence, the true amount of the action of these latter substances cannot 

 be estimated in a single year, and must therefore be altogether a mat- 

 ter of theory until a series of careful observations, made in consecu- 

 tive years, shall afford some decisive facts upon which to reason. 



3°. This is confirmed by the statement of Boussingault and Payen, 

 {Annates de Chim. et de Phys.^ 3d series, iii., p. 94,) that the effect 

 of the animal charcoal of the sugar refiners and of the animalized 

 carbon is, by experience. Jive times greater than the proportion of ni- 

 trogen they contain would indicate ; and — 



4^. If pure oil, which contains no nitrogen at all, will yet produce 

 an enriching manure by mere mixture with the soil (p. 454), or will 

 increase greatly the effect of bones — we must obviously seek for 

 some other principle upon which to account for the effect of manures, 

 besides or in addition to the proportion of nitrogen they contam. It 

 is true that the impure or refuse whale oil used for composts may 

 contain some nitrogen, but we can scarcely suppose 250 or 300 lbs. 

 of such oil to hold so much of this element as to account for all the 

 effects which the oil is said to have produced. 



* As it is sold for manure at Paris and elsewhere, p. 443. 



